there's something that's been bothering me for a while... if mass equals energy anf photon is made of energy, why scientists say photons do not have mass?

maybe i missed something...

Lua,

Scientists don't know what the hell they're talking about. Photons do have mass. That's why they curve when they pass large masses(like stars).

Note to everyone: Spare me the Einstein curved-space crap theory.

Tom

Can a plea stop the rain from falling? Hehe.

tom,



Scientists don't know what the hell they're talking about. Photons do have mass. That's why they curve when they pass large masses(like stars).

they say neutrines (i don't know how to spell it sorry, english is no my first language) don't have either.

was that proven (that does have mass)?



Note to everyone: Spare me the Einstein curved-space crap theory.[/B]

why? in what do you base that?

Scientists don't know what the hell they're talking about. Photons do have mass. That's why they curve when they pass large masses (like stars).

This should be good. Could you please explain to Lua how a photon *with* mass can be 'at rest?' How does a photon *with* mass experience acceleration? Does other mass increase when it's bombarded with photons?

Note to everyone: Spare me the Einstein curved-space crap theory.

Absolutely. We'd rather hear your explanation.

Joeblow93132 generalized:


Scientists don't know what the hell they're talking about.

From this statement are we to feel compelled to conclude that, arising from your own innate appreciation for peer review, your own peers have encouraged you to consider yourself to be an authority on what Scientists actually talk about?


Photons do have mass. That's why they curve when they pass large masses(like stars). Note to everyone: Spare me the Einstein curved-space crap theory. Tom

What should be our motivation for sparing you from your own confusion if not to properly frame your own perspective with some attendant sense of personal gravity?

;)

Mass is not the same as energy. Photons have energy but no mass.


Joeblow:

Some evidence to support your views would be nice. Please explain exactly why you think general relativity is flawed, and how we could experimentally show this. Also, please outline your own preferred explanation, and how we can test that.

Mass is not the same as energy. Photons have energy but no mass[/B]

what about einstein's theory?

I'm a complete beginner in this stuff, but...

I have never agreed with the "space is curved" stuff. And photons, as far as I can tell, were orginally thought of as not particles but as a measurement unit of electromagnetic energy. And to me, everything I have studied so far of EM waves and all that stuff says to me that we are there is more than one thing going on. On the one hand, particles are moving about. They stream through space from powerful sources, they pop out ofa heated wire, et cetera. On the other hand, particles move in response to motions of energy. If you look at the basic way particles move in a wave, it looks like they are bits of cork on an ocean wave, being pushed in various directions not by each other but by some fundamental energy (maybe I'm referring to what some have called the "plenum"). Seems to me we have detected the corks but not the ocean. Anyway, photons (in other words EM waves, whether the ocean or the corks, measured in units called photons) move in paths which are affected by gravity. That seems to indicate to me that either they have mass, or the ocean and gravity interact just as two magnetic fields will interact; whether corks or ocean, obviously there is interaction. However, that curvature of the paths of travel does not indicate that space is curved. It only indicates that the paths are being affected.

Well, that's how it seems to me.

Lua,

As you can tell from the reactions to my comments, most people on this board, and probably most scientists, believe that photons have no rest mass. When they are faced with the question of why the paths of photons curve when passing by massive objects, the say "Well, Einstein says that space is curved around large objects, so the path of photons will curve even though the don't have mass".

I, on the other hand, don't believe that space gets curved because atractive forces also exist in magnetic and electric fields, and these fields can't be explained by the "curved space" theory. Therefore, if you assume that space is not curved, then photons have to have mass or they would always travel in straight lines.

Neutrino's, if I am correct, are thought to be expelled at high speeds, and since they don't react with regular matter, they continue to move at these speeds.(The neutrino was never really proven to exist, it is probably just a theoretical particle that a scientist made up so that his equations would balance out)


Q,


"Could you please explain to Lua how a photon *with* mass can be 'at rest?' How does a photon *with* mass experience acceleration? "


Easy. A photon has mass and a gravitational field. But unlike normal matter, the gravitational field of a photon is BIPOLAR. This would explain why photons accelerate to light speed, and travel at lightspeed. This would also explain why their paths bend when they pass massive objects.


James R,

"Some evidence to support your views would be nice. Please explain exactly why you think general relativity is flawed, and how we could experimentally show this. Also, please outline your own preferred explanation, and how we can test that."

First of all, I have a theory but I don't have the resources to prove it(at least not yet). I believe that gravity is the result of COLLAPSING or CONSOLIDATING space between to massive objects. This is a brief discription: The gravitational field of an object is space with higher or lower amounts of energy(quants). The space closest to a large object has the most energy(gravity), and the energy becomes less as you move away from the object. When two fragment of space(with certain energies) meet, they're energies merge and the become one fragment of space. Since where there were two fragments of space, there is now only one, the objects move closer since the space between them is actually dissapearing. I would like to give an even more detailed explanation, but I have to get back to work.


Tom

The path of photons being curved does not necessarily mean they have mass, I think (again, as you all know, I am a beginner at all this). I don't know, does magnetic force have mass? There is curvature and interaction there...

As you can tell from the reactions to my comments, most people on this board, and probably most scientists, believe that photons have no rest mass.

Photons DO NOT have rests mass.

I, on the other hand, don't believe that space gets curved because atractive forces also exist in magnetic and electric fields, and these fields can't be explained by the "curved space" theory.

You're talking apples and oranges. EM fields have nothing to do with gravity.

Therefore, if you assume that space is not curved, then photons have to have mass or they would always travel in straight lines.

Photons DO travel in a straight line.

This would explain why photons accelerate to light speed,

Photons DO NOT accelerate.

the gravitational field of a photon is BIPOLAR.

Photons DO NOT have a charge.

Lua, it is clear Joeblow does not know what he's talking about. But before you're given the proper responses to your queries, I'd like to hear more about Joeblow theories. It gets better all the time. :D

"You're talking apples and oranges. EM fields have nothing to do with gravity. "

proof this

Photons travel in straight lines? Doesn't gravitational lensing clearly disprove that? And in fact any old refraction? Don't go calling me dumb, just explain it to me please. I'm still learning this.

Q,

If you wan't to try to show off in front of Lau, please don't do it on my expense. Now to correct you're errors:

"Photons DO NOT have rests mass"

Did you put one on a scale or is this just a guess?

"You're talking apples and oranges. EM fields have nothing to do with gravity."

Really!!!You should tell that all the people working on the Unified Theory. You can save them alot of time!!

"Photons DO travel in a straight line."

As Adam pointed out, did you ever hear of a gravitational lens?? Have you looked through a telescope lately?

"Photons DO NOT accelerate."

What about when they pass from a dense medium like glass to a less dense medium like air?? Don't they accelerate to c??

"Photons DO NOT have a charge."

I don't recall saying that they did.


Maybe it's you who doesn't know what you're talking about??


Tom

Hi all,

Adam:

When saying that photons do travel in straight lines, you have to know that we're measuring in a very special way here. Your remark on gravitational lensing is entirely correct: in our three-dimensional world, photons do NOT necessarily travel in straight lines. However, if you start looking in a four-dimensional curved spacetime and use a special "ruler" to measure everything, then they happen to travel straight on. This ruler is called a "metric" in mathematical terms; in our daily world we are accustomed to the Euclidian metric: a straight line is what we expect it to be intuitively (a "line"). In curved spacetime, we use what is called the Riemann metric - this way of "measuring" distances immediatelly takes all the necessary physical effects into account. Photons travel in a straight line in a Riemann sense.

Joeblow,

Please take your time to write down a detailled description. It sounds very interesting indeed, but at the first sight there seem to be some striking similarities with the conventional law of gravity (expressed in energy terms). However, feel free to elaborate.

Lua,

Neutrino's have been proven to have mass. Check out the results on the Superkamiokande detector in Japan (a google search should do the trick). Also, energy does not always equal mass; the formula E = mc² you are referring to is only valid if the object you are studying is at rest. For moving objects (such as photons) the full formula reads:

E² = (m₀c²)² + (pc)²

Here m₀ denotes the rest mass, p the momentum. Substituting m₀ = 0 in this formula yields:

E = pc

Or: for a photon the energy is contained completely in its momentum. I should add that for photons the momentum p is not the classical formula p = mv ;).

Bye!

Crisp

Fantastic, at least now I know what to start reading about. Thanks.

Crisp,

Some day I will post a detailed explanation as a new thread. I still haven't worked it out completely(Still trying to unify the electric and magnetic fields into the theory). It's basically a math problem. Here is what I believe so far:

1. Electric, magnetic, and gravitational fields are not caused by particles traveling at light speed(except photons created by electromagnetic fields). They are stationary and can be considered as part of the particle. They are only a less dense part of the particle that matter can pass through.

2. The three fields to not stop suddenly, instead they get weaker as you move away from the particles. This could be because the fragments of space can only hold energy in multiples of a certain number. As an example, if the multiple is two then the energy values of fragments of space would be 1,2,4,8,16,32, etc. If you had an even number, like 64, the specific field would not exist(it would exist but it would be concentrated in the center of the particle). But if a particle had an uneven number like 63, it would break into 32,16,8,4,2,and 1, in other words, a field would be created that extends beyond the surface of the particle.

3. The most stable fragment of space would be the one with the most energy(taken into account it must be a multiple of a certain number). Example, as explained above, 64 would be more stable than 32. 32 would be more stable than 16, etc. Therefore, when a fragment of space from one mass, with the gravitational value of 4, met another fragment of space from another mass, also with a gravitational value of 4, they would create one fragment of space with a gravitational value of 8. This would cause the two masses to move closer because where there were two fragments of space, now there is only one. This happening to billions of particles at the same time could explain the attraction forces in gravitational, magnetic, and electric fields.(Unfortunatly, I still can't explain the repulsive forces).

That's all for now. I'm getting tired. Any feedback would be apreciated.

Tom

Cest moi

You're talking apples and oranges. EM fields have nothing to do with gravity. "

proof this

Good catch. My bad. EM fields DO have something to do with gravity. I hastily and incorrectly worded my response. I was using the statement in context with the statement made by Joeblow. I will now consider my wrist, slapped. Thanks for that. :D

Electromagntic radiation is basically light or photons moving at the speed of light carrying some energy. The difference between a radio wave and a gamma wave is the amount of energy they carry. They DO NOT carry a mass. GR says that anything that carries energy, momentum and stresses is a SOURCE of a gravitational field, that is, a curvature of spacetime. Therefore it is the SOURCE of the EM field that distorts spacetime by virtue of it's matter.

Magnets, for example, are manifestations of certain types of matter, and carry energy. Therefore they will have a gravitational field and will distort spacetime. Because an electromagnetic field contains energy, momentum, and so on, it will produce a gravitational field of its own. This gravitational field is in addition and is infinitesimally small to that produced by the matter of the magnet.

Adam

Photons travel in straight lines? Doesn't gravitational lensing clearly disprove that? And in fact any old refraction?

That is correct. Photons travel in straight lines. To understand curvature of spacetime is to understand the notion of a manifold. A manifold is basically a curved space, which, in small enough regions, looks like flat space. For example, the Earth looks flat from our ground dwelling perspective because we only see a tiny part of it, even though it is round. The photon moves along a geodesic which is the shortest distance between two points. The curved manifold of space will therefore make the geodesic appear curved. The photon will therefore move along a geodesic (shortest distance) that has been curved by a massive object. Gravitational lensing works under the same principles.

Look up Riemann tensor and geodesic equation for the math.

"Photons DO NOT have rests mass"

Did you put one on a scale or is this just a guess?


Light is composed of photons so we could ask if the photon has mass. The answer is then definitely "no": The photon is a massless particle. According to theory it has energy and momentum but no mass and this is confirmed by experiment to within strict limits. Even before it was known that light is composed of photons it was known that light carries momentum and will exert a pressure on a surface. This is not evidence that it has mass since momentum can exist without mass.

http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html

"You're talking apples and oranges. EM fields have nothing to do with gravity."

Really!!!You should tell that all the people working on the Unified Theory. You can save them alot of time!!

"Photons DO travel in a straight line."

As Adam pointed out, did you ever hear of a gravitational lens?? Have you looked through a telescope lately?

Answers are in above post and in General Relativity.

"Photons DO NOT accelerate."

What about when they pass from a dense medium like glass to a less dense medium like air?? Don't they accelerate to c??

No. Photons NEVER accelerate. They are propagated instantaneously at 'c'. A photon is simply energy released from an electron that has a change in its energy state. An electron will increase its energy state when it absorbs a photon and decrease its energy state when it releases the photon.

"Photons DO NOT have a charge."

I don't recall saying that they did.

No. You inferred it with your statement: the gravitational field of a photon is BIPOLAR

Q,

You just contradicted yourself. Mass is known by two things: its gravitational field or gravitational interaction AND, as you pointed out, it's momentum.

Funny, because photons have both. They're paths curve when they approach massive objects, and they exert a force on objects they hit.

How am I supposed to prove that photons have mass, if can't use the two most important properties of mass as the proof?

Note: Photons slow down as they enter into denser matter like glass, and they accelerate back to c when they exit it.

Tom

Q,

Nice link(If you assume the Theory of Relativity is correct)

Tom

Nice link(If you assume the Theory of Relativity is correct)

Oh oh! Now you've done it! Didn't Einstein once say that it will be one experiment that will prove relativity wrong. So far there have been countless experiments, millions if not billions of dollars spent and a parade of scientists throughout the past 80 some years that have tried to find that one experiment. All have failed. Relativity works.

For the record, I did not contradict myself. Photons do not have mass, they follow straight lines and they do not accelerate.

That said, it looks like we've reached a stalemate. I will only be repeating myself. Good luck on your theory. :)

Q,

Maybe, over the last 80 years, people have so blindly accepted relativity that no one attempted to prove him wrong. And if they did, would you listen?

I personally don't understand how so many people can believe a theory like relativity that's so illogical.

Maybe people just use their imagination too much. Was it Einstein who said "Imagination is more important than knowledge"? I'm sure he meant imagination is more important than reality.

Tom

Excuse me guys, I would like to take a moment to pull out my soapbox and make a little speech. Thanks in advance. :D

We have in the Global Positioning System (GPS) an example of an actual engineering system in which the special and general theories of relativity are not merely of scientific interest, but rather are essential to its operation. The GPS serves as a kind of laboratory for the demonstration of relativistic effects on satellite clocks and as a model for the appropriate application of relativity algorithms in other systems.

Typically, the effects of relativity become important for individual time measurements made to a precision of one microsecond or better. For any satellite system in which there are on-board clocks and on-board time-tagging of events, it is possible that relativistic effects may be even more dramatic than in the case of GPS, such as a satellite in a highly elliptical orbit. It is therefore important that these effects should be appropriately identified and taken into account.

Lets not forget about the countless experiments done in particle accelerators that extend the lifespan of a radioactive particle by double, triple and even more times it's original. How? They use Relativity. They accelerate the particle to about 99% the speed of light and its radioactive lifespan (from our viewpoint) becomes much longer than the same particle at rest. This conforms exactly to Relativity. There's no doubt about it, relativity works. You can believe otherwise, but then you would have to explain why it works so damn well for every experiment we can think of :)

Photons do not have rest mass. If they did, it would be impossible for them to accelerate to their current speed. Their apparent mass increases as their kinetic energy increases. Suppose you found a photon at rest. It has no mass. Theoretically, any amount of energy could be applied to it to acheive an instantaneous velocity of c. Since there is no mass to overcome, any amount of energy will do. Once it reaches c it has apparent mass due to it's energy. For this reason it will still curve in space, because it does have mass as long as it's moving.

btw, don't quote me on that thought experiment, I really don't know if it's right, just something I thought of. ;)

JoeBlow,

A good maxim to bear in mind is "Know thy enemy."

You can't begin to try to refute a theory unless you first understand what it says. I therefore suggest you go away and read up on general relativity. Then you won't look so silly when you try to explain what that theory says and why it is wrong.

To get you started, here are a few predictions of general relativity:

* photons have no rest mass.
* photons always travel at the same speed, according to all observers. They do not accelerate.
* photons have energy and momentum.
* the path of light can be bent by the gravity of a massive object due to the curvature of space and time.

Just thought I'd throw this in. About light slowing and accelerating when entering different media; the light only seems to slow down because it takes the entire waveform of the light pulse longer to get through the material. The individual particles are still travelling at c, but there is now more stuff "in the way" that they have to contend with. Thus, it seems as if the light slows down, when in fact the entire pulse of light is still travelling at c.

Again, if I'm wrong here, someone correct me. I'm still learning ;)

Photons striking the electrons of a transparent material will be absorbed and then re-emitted. The photons are passed along from one atom to the next until they are re-emitted out the other side of the material.

That's what I meant. And since there are more atoms inside a denser material (ie. more electrons) the photons will be absorbed many more times than if they were travelling through a vacuum. Thus, they appear to be travelling slower, while they actually aren't.

Am I at least on the right track? :)

Yes, that's more or less right, Xelios.

This is a most interesting thread.

From the very start of wave mechanics (I have only had introductory classes so far), it seemed to me that these EM waves (which is what this is all about) were not the motion of particles at all. If you look at one of those demonstration diagrams of how particles act at various stages of a wave (exam questions: which way do the particles move at these points due to the wave? that sort of thing) it looks not like the particles are propagating through space, but as though they are being moved by motions of energy fields. Just as iron filings move to the will of magnetic fields. I personally think so far that (not counting atomic decay, alphas and betas and all) EM propagation or fields is much the same in its interaction with mass as plain old magnetic fields and iron filings. So in looking for mass of the photon, we will find particles which are affected by these things but are not actually the component matter of these things.

Question: If all photons instantaneously propagate at light speed, why do photons not travel at light speed? Seems to me that even from the moment of creation, they travel at most at C/refraction index. Thus all those experiments involing slower light. Or is that idea of all photons propagating at C just a short-hand slang so people don't have to go into all those extra bits?

Question: There's all this talk of photons as discrete particles. I was under the impression that "photon" was originally used as a way of conceptually working with a quantity of light or some other part of the spectrum, but was not actually a particles. More like a unit of measurement such as a litre or a metre. Indeed, my astronomy textbook defines a photon as a unit of measurement of electromagnetic energy rather than a particle. So it seems to me that when people refer to the mass of a photon, it makes about as much sense as talking about the mass of a metre. Can someone explain this further please?

If all photons instantaneously propagate at light speed, why do photons not travel at light speed? Seems to me that even from the moment of creation, they travel at most at C/refraction index.

From what I understand, the speed of light is always constant. No matter what material it moves through, photons will always move at about 3x10^8 m/s. The reason it looks as if light slows down inside a refractive medium is because there are more electrons to absorb the photons and then re-emit them. This takes time, and although it happens very quickly, it can happen several million times to a single photon. This increases the time it takes for a photon to traverse the medium, which suggests that the photon is travelling slower than it would be in a vacuum (if the length of the journey is kept the same).

As for your second question, I'll let James R. answer it as he probably knows more about it than I do ;)

James R, Xelios, and Q,

You are all wrong about the belief that photons get absorbed and re-emmited as they pass through dense material like glass. Glass is optically inert. The atoms in the glass do not absorb any photons. If a material did absorb photons, it would likely only absorb a specific wavelength, and not the entire spectrum. Not only would they absorb a specific wavelenght, but the re-emmited photons would likely be a different wavelength than the original photons. And finally, If there was a material that can absorb the entire visual spectrum, some photons would still get through without absorbtion. In this theoretical medium, there would be two waves of photons, the ones that did not get absorbed(traveling at c), and the ones absorbed and re-emitted(those appearing to travel below c). Since no material has ever been found that obeys this two-wave theory, you're absorbtion/re-emmited theory is flawded.(By the way a few materials do absorb and re-emmit photons, the phenomena is called fluorescents).

Adam is right, only in space does light travel at c, in all other mediums it is slower.

Tom

I was wrong regarding my last post. There are materials that absorb the photons of the entire visual spectrum, those materials are called black. They absorb light and re-emit it as infrared radiation. Green objects absorb all visual light except blue and yellow, while red objects absorb all visual light except red, etc. Transparent materials, like glass, DO NOT absorb any photons. Their atoms require too much energy to push their electrons into higher orbits.

Tom

Adam,

Regarding your second question, photons are considered particles and waves(or disturbances) at the same time. When photons curve around stars, and when they produce forces when they hit an object, they are considered particles. It has even been found that atoms recoil, like a gun, as they emit photons indicating that they may have mass, therefore they are particles.

Under other circumstances, photons obey as if are electromagnetic disturbances propagating through space like a wave on the ocean.

So are photons waves or particles? That's a question that hasn't been answered yet.

Tom

So are photons waves or particles? That's a question that hasn't been answered yet.

Both.

Transparent materials, like glass, DO NOT absorb any photons.

What do they do then? Do the do they not interact with the photons at all? If that was the case, the photons would travel through the medium unimpeded, meaning they would travel at c no matter what medium they travelled through (as long as it was transparent). You say yourself this does not happen, that the photons travel at a slower speed in a refractive index. So what does happen? Do they just magically know they should be travelling slower?

Adam,

A photon is a quantum of the electromagnetic field. It behaves in many ways like a particle. It carries a particular amount of energy and momentum and is localised to a small region of space at any time. To all intents and purposes, it is a particle.


Joeblow,

You are right that clear glass does not totally absorb photons passing through it. The energy levels in glass absorb light at frequency of UV and above, but not visible light. However, frequencies below the absoption frequencies interact with "virtual" energy levels below the absorption levels in the glass, and those interactions take time.

Glass exhibits <b>dispersion</b> effects. It has a slightly different refractive index for different frequencies of light, corresponding to the different energy gaps between the light frequencies and the energy gaps in the glass. What that means is that different colours of light <i>do</i> travel at different speeds through the glass, and this is well described in the literature.

"However, if you start looking in a four-dimensional curved spacetime and use a special "ruler" to measure everything, then they happen to travel straight on."

this spacetime reminded me of Aspden who told following:-

<<The word 'spacetime' is itself a presumptuous term if one is intent on engaging in a debate about the physics concerned with the nature of the universe. I am reminded by a conversation I once had at Cambridge with Dr. Sciama, the university don who supervised the Ph.D. research of Stephen Hawking. I was seeking to interest Dr. Sciama in my theory of the aether, stressing its quantum connection by its theoretical evaluation of the fine-structure constant and its relevance to gravitation. Nothing came from that conversation other than a comment which stands in my memory. Dr. Sciama said:

"We all believe there is an aether but we never use that word; instead, we call it 'spacetime'".

I may add that Dr. Sciama and I were both members of Trinity College, Cambridge and were awarded our Ph.D. degrees in the same year, 1954.>>

as for all those discussions on photons: there are at least 4 main models in quantum physics for photons which all contradict each other but whom all work in different situations
seems we have a long long way to go for finding out a proper theory for that

and for all those discussions concerning mass and energy, I find that strange
isn't mass 'frozen' energy?
further, what is mass?
what is energy?

science has its limits, it can't tell WHAT something is, just say what it does
but I guess that asking WHAT something is, is actually a wrong question (the same position I take in regard to time)

can someone give some valuable critical view of this theory of Sansbury? (sorry, but it seems his website is just gone)
if you don't know his theory, never mind then

sometin' went wrong
here is the full quote


this spacetime reminded me of Aspden who told following:-

The word 'spacetime' is itself a presumptuous term if one is intent on engaging in a debate about the physics concerned with the nature of the universe. I am reminded by a conversation I once had at Cambridge with Dr. Sciama, the university don who supervised the Ph.D. research of Stephen Hawking. I was seeking to interest Dr. Sciama in my theory of the aether, stressing its quantum connection by its theoretical evaluation of the fine-structure constant and its relevance to gravitation. Nothing came from that conversation other than a comment which stands in my memory. Dr. Sciama said:

"We all believe there is an aether but we never use that word; instead, we call it 'spacetime'".

I may add that Dr. Sciama and I were both members of Trinity College, Cambridge and were awarded our Ph.D. degrees in the same year, 1954.

The more I learn in physics, the more mysteries I encounter. The more theories I learn about "what is", the more holes I find. This is very frustrating. One day I intend to solve all these problems, possibly with the help of tarot cards or beer or both.

Hi Adam,

There is a reason why this discussion takes place in the "Frontier Physics" forum ;). The truth is that we indeed have good theories that describe how things work - the most fundamental "what" questions is exactly what we're trying to answer with high-tech theories such the stringtheories. There are several variants, and to be honest, I don't think we're going to find out which one is the most correct anywhere soon.

I guess Max Planck could have been right when he said: "New theories do not prevail because they convince others and let them see the light, but simply because all opponents die out and a new generation, that is familiar with the theory, grows up" ;).

But no reason to be pessimistic: the theories we have explain a lot of phenomena in terms of basic assumptions on how nature works. Quantum mechanics assumes a wave/particle duality for everything in nature, and it works darn well. The questions we're asking ourselves here are in the line of: "is it REALLY both a particle and a wave?". Allow me to give a question as an answer: "does it matter? do we need to know that ?".

I think it doesn't matter and that we don't have to know all the answers to the "what is it" questions. Or like C'est Moi argued: "that is actually a wrong question". What most people seem to forget here (I also do that from time to time ;)) is that science CANNOT hold the absolute truth. Science works by inductive reasoning: from a series of experiments we try to formulate a general law that predicts the outcome if we do that series of experiments again. We can never verify this law to be entirely correct since that would involve doing an infinite number of experiments - anyone up for an infinite life? What science does is model nature in a scientific (read: mathematical) formulation, and a model is never perfect; simplifications are made, assumptions are made and if in the end, everything seems to turn out well, this model is used for describing nature.

The kind of questions science can answer are for example: "if I hold this pencil above my desk and let go of it, will it fall ?". The answer is obviously yes (no scientist will dispute that). But if you ask WHY the pencil falls, then you'll get a whole range of answers about gravity: "it's because of Newton's second law" or "the pencil follows a straight path in the curvature of spacetime". In the end, all these different answers relate to the different models of nature you use to describe the pencil falling (be it a Newtonian model of gravity, Einstein's general theory of relativity or an experimental theory of quantum gravity). The answer depends a lot on the scientist you're asking: does (s)he believe the assumptions the model makes, does (s)he agree with the simplifications or does (s)he wants a more detailled description ?

So to conclude this part: the "why" and "what" questions are IMHO not answerable with science, only the "what if" questions.

You could be asking yourself why a certain model of nature (or theory) is more popular than another model. I believe that there's no consensus on that either ;) - as I quoted above, Max Planck thought it was a matter of time. Thomas Kuhn argued that no consensus is possible. Personally I think Henri Poincaré hit the nail on the head when he argued that the preference of one theory over another is simply a matter of convention: if both theories work, then it's up to the scientific community to decide which one they like to use. One of the best examples here is the theory of special relativity: you can use a perfect Euclidian world to describe relativistic effects (but that package comes with aether and unexplainable Lorentzforces that deform clocks and lengths) or you can use the Einstein/Minkowksi description which gives up the idea of aether, explains why clocks and lengths are deformed, but uses the assumption that the speed of light is a constant for all observers. Both theories work: they can both explain some of the wierd effects we see when going at high speeds. However, the scientific community choose Einstein's theory (probably because they didn't want those wierd deforming Lorentzforces to handle). But whatever theory becomes "mainstream" - it's entirely a human choice.

It's not really the most appealing image of science, but IMHO that's the way it is: because of our human inability to know "everything", we can never say something for sure.

Just my thoughts ;)

Crisp

Interesting post.

My own view is that science is merely trying to understand the universe, that's all. So I can never understand when people say "science is a new god". Doens't make sense. Science is something we DO, like breathing or running. I see no cause for comparison with mythical beings. Nature didn't give us claws and armour; it gave us science, our ability to learn, make and use tools, et cetera. And it rocks. Well, that's my view, very simple.

About the "speed of light is the same for all observers" thing. I thought that was more than merely an accepted convention. Seems to me it is a basic physical property which has been demonstrated hundreds of thousands of times in experiments. And there's not even anything tricky about it. All it says, to me, is that electromagnetic energy of a given type/flavour/whatever will always have the same velocity in a certain material. In our atmosphere, for example, regardless of how fast any observer is travelling, light will always travel at the speed C (a numerical constant around 300 million metres per second) divided by the index of the air. A very simple physical rule. If the object emitting that light is going twice the speed of light, it doesn't matter; the light may still only travel at the speed already defined for light in that medium. So yes, it seems more than convention to me; it seems a rather solid and reliable physical property. However, I don't yet see how that one physical rule about the propagation of light through various media restricts anything from exceeding that speed. I have not yet gone into the relativity stuff, the mass at nigh-lightspeed equations and all.

Sorry for rambling and taking this thread off in all sorts of directions, but that's the way I learn things, by following my interest.

Originally posted by Xelios
[BWhat do they do then? Do the do they not interact with the photons at all? If that was the case, the photons would travel through the medium unimpeded, meaning they would travel at c no matter what medium they travelled through (as long as it was transparent). You say yourself this does not happen, that the photons travel at a slower speed in a refractive index. So what does happen? Do they just magically know they should be travelling slower? [/B]

You are almost right with that last statement.

The speed (note that speed is a scalar quantity) of light in a medium is dependant on, amongst others, two things. The relative permittivity and relative permeability of the medium, relative to these values in vacuo. When a wave front crosses a boundary between mediums it slows or speeds up immediately. (It does accelerate). This is manifest as the wave front changing direction, it refracts. The amount of refraction depends also on wavelength, which is why white light seperates into a spectrum through a refractor.

In essence, the refractive index of a substance is a measure of the resistance to a light wave that the substance has.

Important point here, the speed of light is scalar and is invariant between frames of reference. How then can a light ray accelerate? Acceleration is a change in speed OR a change in direction. If light changes direction it accelerates.

So, as light always travels in straight lines and its speed is invariant how can it change direction. That which we perceive as a straight line in 3D space is curved but is a straight line in 4D spacetime. The amount of curvature is caused by gravity.

I am using the argument the wrong way around. What Einstein reaised is that gravity and acceleration are indistinguishable. If light passes through a gravitational field IT MUST accelerate. The only way it can do this is change direction. But if space is euclidean it can not. Ergo, space is non-euclidean. In others, its bent, curved, twisted or whatever.

If people want to dismiss Einsteins Relativity they have to first start with disproving the equivalence principle (gravity and acceleration are the same) then the rest of the argument.

As some one pointed out, the gravitational lenses that have been found are powerful evidence of the validity of Einsteins work.

About optics and permittivity, permeability, refractive indices.

http://www.cem.msu.edu/~cem835/Lecture03.pdf

Also look 'optical path'

It's truly wonderful how many clever people still get it wrong when discussing theories.
I believe Crisp explained it very well. And I believe my quote of Aspden made that one very clear also...

http://www.energyscience.co.uk

Many people on this board are claiming that photons have no mass and their paths curve when passing large masses because the large masses curve space. Yea right!!

Unfortunatly, many people on this board are "textbook geniuses" and unable to think for themselves. Their answer for all questions regarding physics is "Cause Einstein says so!"

For a second, let's assume Einstein was right and photons do not have mass. Maybe people don't have mass either. Maybe we are just held to the Earth by the Earths curved space!!

Tom

Tom, if photons had mass they could not travel at c. Since they do travel at c, they have no rest mass. End of story. They still have apparent mass, which comes from their motion. So they are still affected by gravity (whatever you may think it is) because of this mass gained from their motion. Your arguement that photons do have rest mass is flawed in that it contradicts almost every observation made concerning photons and the speed of light.

cest moi,

It is disappointing to see Harold and Dennis's names brought up in scientific discussion. But perhaps you've brought in the aether twins as a humorous interlude? If so, thanks, I had a good chuckle.

I saw in either New Scientist or American Scientist recently a huge article or set of articles about the "aether" or plenum or whatever they want to call it now. There are a LOT of researchers in many countries who believe there MAY be something to it, and who have found unexplained phenomena in their experiments which MIGHT lend credence to such ideas. Whatever the truth, they aren't yet ready to rule it out completely. I think it is far too early for people to dismiss that whole thing as fairy tales.

I'm quite happy with the idea that photons (whatever people think they are) have no rest mass at all. However, I also think in this case that it is far too early to say "end of story".

There's far too much we don't know, in both those cases.

"It is disappointing to see Harold and Dennis's names brought up in scientific discussion. But perhaps you've brought in the aether twins as a humorous interlude? If so, thanks, I had a good chuckle."

no thanks m8

maybe you good give some argumentation now that clarifies your answer

why is aspden able to derive the law of gravitation without using relativity, using maths and logic that normal people still comprehend? occam's razor cuts very sharp here

why is aspden able to derive the law of gravitation without using relativity, using maths and logic that normal people still comprehend?

You can use math and logic to satisfy the concept of wormholes and white holes, but the reality is very different.

occam's razor cuts very sharp here

Not sharp enough I'm afraid. Special Relativity came along and occam's razor sliced right through. :D

So much for the redundancy of the aether theory. I'm starting to get the impression that you're inferring there is a problem with SR?

Right then let's assume that Einstein is wrong. As is every one who came after and a few before.

So, first question is, what is light? Is it a particle or wave. Newton realised that shows properties of both. Maybe we should do some experiments to investigate things. After all, the thousands of experiments and conclusions found in the last 150 odd years are all wrong. Any ideas?

What does light travel in? If its an Aether that Aether exists every where. This means it must have zero density, other wise you would feel it dragging on you. Assuming it carries waves it must have infinite elasticity, otherwise light would loose amplitude, quickly. Do you know any infinitely elastic but zero density materials? Actually, its an absurd idea so I'll wait for your answer.

How about this electricity and magnetism stuff. We can assume Maxwell is wrong, after all his theory led into Relativity. So what are they? Why does a moving magnetic/electric field create the other?

How about atoms? Mass, energy equivalenc forms a cornerstone of QM so we can throw out every thing we know about atoms, its based on Relativistic concepts. Any ideas? What is matter made of? What is charge?

Hmmm, strange that Physics is so wrong yet it built an Atom bomb, radios, broadcast, silicon chips, predicted the cosmic microwave background, predicted the displacement of stars positions by the Sun, Black Holes, gravitational lenses etc.

Maybe you have a better explanation than those boring physicsts how are 'text book geniuses'.

Do I believe in materials with zero density or infinite elasticity? Belief is irrelevent. Three hundred years ago people did not believe in nuclear weapons, lasers, GPS systems, and mircowave ovens. The question is pointless.

Talking about the aether like that is, in my beginner's opinion, very bad science. Saying it would have to be zero density, so it doens't exist, et cetera. What you are doing there is saying "According to what we know now, that CAN NOT exist. So it's really stupid to look for furtehr information about the universe." Obviously science would not have progressed very far if there were too many people like that involved. The fact is we do NOT know what we can not yet detect. To say that therefore it is not real is presumption and detrimental to the goal of science, that being to learn about the universe.

I don't think anyone in this thread has said physics is wrong, that Maxwell's equations don't work, et cetera.

thed,

I'll try to answer some of your questions, but I don't know everything either. What I do know is that Relativity DOES NOT make sense. There are more then one way to explain a phenomena and Einstein's way was wrong.

"So, first question is, what is light? Is it a particle or wave. Newton realised that shows properties of both."

Thank you for admitting that photons are particles. I guess since the main property of a particle is mass, a photon must have mass. There goes Einsteins theory about photons being PURE energy.

"What does light travel in? If its an Aether that Aether exists every where. This means it must have zero density, otherwise you would feel it dragging on you. Assuming it carries waves it must have infinite elasticity, otherwise light would loose amplitude, quickly. Do you know any infinitely elastic but zero density materials? Actually, its an absurd idea so I'll wait for your answer."

Very foolish question. You assume that all matter must exert a drag on other matter. Does a superconductor exert a drag on the electrons traveling through it? Does the strength of the electron's electric or magnetic fields diminish with time as it travels in the superconductor?? I guess a superconductor must have "zero density and infinite elasticity""!!!(sarcasm).

"How about this electricity and magnetism stuff. We can assume Maxwell is wrong, after all his theory led into Relativity. So what are they? Why does a moving magnetic/electric field create the other?"

Funny you should ask me. Wasn't it Einstein who completely ignored magnetic and electric fields. Answer this : What is Einsteins theory for the attractive and repulsive forces of electric and magnetic fields??Oops, he doesn't have one. He had a crazy theory about curved space but it ONLY applied to gravitational fields.

"How about atoms? Mass, energy equivalenc forms a cornerstone of QM so we can throw out every thing we know about atoms, its based on Relativistic concepts. Any ideas? What is matter made of? What is charge?"

Interesting that you should mention E=mc^2. As far as I know, most people don't even have a definition for energy. What is you're definition of energy?

Try contacting a physicist who worked at Los Alamos in the 40's. Ask him/her what they thought about E=mc^2 after they detonated the first atom bomb? You'll be surprised!!

"Hmmm, strange that Physics is so wrong yet it built an Atom bomb, radios, broadcast, silicon chips, predicted the cosmic microwave background, predicted the displacement of stars positions by the Sun, Black Holes, gravitational lenses etc"

I never claimed physics was wrong, I claimed Einstein was wrong. Unlike you, I don't believe that Einstein and physics are one and the same.

Tom

Thank you for admitting that photons are particles. I guess since the main property of a particle is mass, a photon must have mass. There goes Einsteins theory about photons being PURE energy.

So if photons are simply particles, would you mind explaining how they set up interferance patterns in a double slit diffraction experiment? If they were only particles, you would expect just a random spattering of dots on the photoreceptive plate wouldn't you? But alas, that doesn't happen. Any ideas?

He had a crazy theory about curved space but it ONLY applied to gravitational fields.

So?

Try contacting a physicist who worked at Los Alamos in the 40's. Ask him/her what they thought about E=mc^2 after they detonated the first atom bomb? You'll be surprised!!

Why would I be surprised?

I claimed Einstein was wrong.

You may claim all you wish. Nevertheless, the vast majority of experimental data conforms to the theories of Relativity. Calculations involving relativity are made every day to a very high degree of accuracy. Atomic clocks accurate to tiny fractions of a second have revealed a difference in the passage of time at different lengths from Earth's gravity well, just as Einstein predicted. Experiments in particle accelerators have found we can accelerate say, an electron to 99.99% the speed of light, but not quite over it. Just as Einstein's theories predict. The radioactive half lifes of particles have been observed to double, triple, quadrouple and more in particle accelerators when travelling at close to light speed. This is due to the slowing down of time relative to the particle, just as Einstein's theories suggest.

All these things, and many more, have conformed almost exactly to relativity, and yet you are here trying to convince me it's all absurd without even going so far as to provide an alternate theory.

Thed said: "So, first question is, what is light? Is it a particle or wave. Newton realised that shows properties of both."

Joeblow said: Thank you for admitting that photons are particles.

Read carefully Joeblow, Thed said specifically "shows properties." It was already mentioned before the photons exhibit properties of momentum and energy. It could also be shown that a baseball bat can exhibit particle and wave properties. :D

Xelios,

"Try contacting a physicist who worked at Los Alamos in the 40's. Ask him/her what they thought about E=mc^2 after they detonated the first atom bomb? You'll be surprised!!

Why would I be surprised?"

I can't be sure, but when I was younger I heard from a physicist that the detonation of the first atomic bomb surprised the physicists at Los Alamos because the explosion was more powerful than the formula E=mc^2 indicated it would be.

"So if photons are simply particles, would you mind explaining how they set up interferance patterns in a double slit diffraction experiment? If they were only particles, you would expect just a random spattering of dots on the photoreceptive plate wouldn't you? But alas, that doesn't happen. Any ideas?"

I didn't say that photons were only particles, I said they were particles. And as such, must have mass.

And as I said before, there are different ways of looking at things. Here's an example.


Lets say you lived during the Roman Empire and you believed that the world was flat. If you held a rock in your hand and then dropped it on the ground, you could argue that you and the Earth rose up to meet the ball, instead of the ball falling to meet the Earth. You may even be able to prove it using formulas and equations. But your theory would be wrong. The only way to prove that you were wrong would be if you stepped back and looked at the whole picture.

Einstein made a similiar mistake. When you look at things locally, relativity may be able to explain them. But when you step back and look at the whole picture, then you will see that relativity no longer makes sense.

Example: Time slows down when matter approaches light speed.

Is time seperate from matter? Could it be that time is constant but reactions are slower? A catalyst will speed up a chemical reaction, but won't it appear as if it's making time go faster?

Example: An object can never reach light speed because it's mass would be infinite.

What about super blackholes, like the ones in the center of galaxies. Wouldn't their be enough distance and gravitational force to speed up an incomming object to c?
If you can't push an object to c because of it's mass, what about pulling it with gravity??

Example: Gravity is the result of curved space.

What about the forces in electric and magnetic fields? Are they also the result of curved space? If not, can gravity be explained using the same theories that would explain magnetic and electric fields?

As you can see, physical phenomena can be looked at in different ways. As you know, there are already people claiming that they can prove all relativistic phenomena using only classical physics and common sense. What would you prefer: explaining the universe using relativity and classical mechanics, or explaining the universe using ONLY classical mechanics? I would prefer the latter.

So finally, do I have a theory that would replace relativity? The answer is no, but I'm working on it. Unfortunately, I'm not a physicist so I can't spend my entire day trying to prove Einstein wrong. But believe me, one day someone will come along and prove that Einsteins Theory of Relativity is wrong, and everyone will be wondering why they ever believed in such an illiogical theory.

Tom

I can't be sure, but when I was younger I heard from a physicist that the detonation of the first atomic bomb surprised the physicists at Los Alamos because the explosion was more powerful than the formula E=mc^2 indicated it would be.

I doubt it. Nuclear reactions are not even 100% efficient at converting matter to energy, so if anything the energy created would have been much less than predicted by E=mc^2.

If you can't push an object to c because of it's mass, what about pulling it with gravity??

It wouldn't matter if you pushed or pulled, accelerating a massive particle to light speed requires infinite energy, which is why it can't be attained.

What about the forces in electric and magnetic fields? Are they also the result of curved space? If not, can gravity be explained using the same theories that would explain magnetic and electric fields?

Possibly, however at the moment curved space is the best answer to the gravity question. If gravity were a field you would have to explain how the light from a star bends around a massive object such as the sun (which is visible during an eclipse).

But believe me, one day someone will come along and prove that Einsteins Theory of Relativity is wrong, and everyone will be wondering why they ever believed in such an illiogical theory.

I doubt it will be completely wrong. At the moment it does it's job very nicely, perhaps a century from now we will develop a new understanding about physics and formulate new theories that differ from Einstein's, but I'm sure they will incorporate some of the same concepts. Einstein may be partially wrong in the long run, but to call his theories absurd is just naive.

Joeblow,

<i>Wasn't it Einstein who completely ignored magnetic and electric fields. Answer this : What is Einsteins theory for the attractive and repulsive forces of electric and magnetic fields??Oops, he doesn't have one.</i>

I don't know where you get your information about Einstein from. His first paper, introducing special relativity in 1905, was titled "On the Electrodynamics of Moving bodies".

Yeah, he didn't incorporate electromagnetism. Right. LOL. :)

"You can use math and logic to satisfy the concept of wormholes and white holes, but the reality is very different. "

jeesh, what are comparing this to
do you know the law of gravitation? I suppose so, then what has this to do with white holes etc.

"So, first question is, what is light?"

has nothing to do with SR
it says light has a constant speed c which cannot be exceeded, that's it

"What does light travel in? If its an Aether that Aether exists every where. This means it must have zero density, other wise you would feel it dragging on you."

compare it to fluid crystals

"How about this electricity and magnetism stuff. We can assume Maxwell is wrong, after all his theory led into Relativity."

Maxwell's equations assumed the existence of an aether
they haven't been changed so they still do

"Mass, energy equivalenc forms a cornerstone of QM so we can throw out every thing we know about atoms, its based on Relativistic concepts."

E=mc² predates Einstein

"What is charge?"

a property

What is time? What is energy? All wrong questions.

I think what you've just showed us is a complete lack of knowledge and understanding of what Einstein's theories stand for. It is much more about interpretation than naked facts. Dragging in technology is also irrelevant.

"This is due to the slowing down of time relative to the particle, just as Einstein's theories suggest."

slowing down of time is the interpretation of it
does that mean that time really slows down? Nope
atomics clocks going at different at high speeds etc. are due to increase of kinetic energy

see http://www.newtonphysics.on.ca/kinetic/length.html for example

before marmet wrote this paper, i had figured that out, just oversimplified

now, what will be favored by occam's razor? I am not asking you for the 1000s of experiments that seem to support relativity
I am asking for this small example: which one should be accepted taking occam's razor into account? a theory insisting that time is slowing etc. or the principle of mass-energy conservation in this case increase in kinetic energy?

people, please stop being so irrational when discussing theories
first of all there is the INTERPRETATION which can be very very different
who said Einstein is useless? it's usefull, but there seem to be a growing body of evidence that things can be explained much more easily than relativity does
Easier is Better.

Easier is better only if there is no loss in quality. But lets say you can explain the slowing of time (or lack thereof) using that link. What about the differences in length of an object when travelling at different speeds? Is there a simple explanation for this as well? What about the slowing of time just above a black hole's event horizon? If an object were to hover just above it, it would have no kinetic energy because it isn't moving. Yet, time still slows for the object due to the intense curvature around the black hole. Can this be explained simply as well?

Originally posted by c'est moi
"You can use math and logic to satisfy the concept of wormholes and white holes, but the reality is very different. "

jeesh, what are comparing this to
do you know the law of gravitation? I suppose so, then what has this to do with white holes etc.

C'est mois, do you know General Relativity? Wormholes are otherwise called Einstein-Rosen-Podolsky Bridges and Wormholes are a result of the Schwarzschild metric being symmetric.

The point that you totally missed is that the maths allows these exotic objects but that does not mean they have physical reality.


"So, first question is, what is light?"

has nothing to do with SR
it says light has a constant speed c which cannot be exceeded, that's it

Au contraire, it has everything to do with special relativity.

Before Maxwell unfied electrical and magnetic forces into electromagnetism and explained light there was no description of what light was. I am using light as a generic descriptor for any EM wave.

The problem, is you are not aware of it, is that Maxwells equations can not be easily transformed by the Galilean transform, pre-Relativistic phyics. Lorentz realised that the transforms worked if you made some wacky assumptions like time slows and length contracts at light speed. The &gamma; correction in SR in other words. Einstein realised the physical signifinance of this. As Jame R points out his first paper was entitled "on the Electrodynamics of moving bodies". So, the nature of light and Einsteins theories are closely entwined.

If Einstein is wrong, so is Lorentz. If Lorentz's transforms are wrong we are back to physics in the 1800's. Another point you and Joeblow totally missed.

So, we know have to start again. As Maxwells equations do not work under a Galilean transform (which is well understood and time tested) and applying occams razor, Maxwell is likely wrong.

So we know have to explain what is electricity, magnetism and light again. We have to find new theories that correctly explain these phenomen and work under the Galilean Transform.

Alternatively, Lorentz and Einstein got it right other wise a lot of other physics is wrong (another point you have missed totally), physics used to build the technology of today

So, I'm waiting, what is yours and Jowblows alternative to Maxwell that works with Galilean transforms and fully explains every experiment ever done in this field?


"What does light travel in? If its an Aether that Aether exists every where. This means it must have zero density, other wise you would feel it dragging on you."

compare it to fluid crystals

Non Sequitor!

You are evading the point, completely. Central to modern physics is the idea that light travels in no medium. It was largely thought to prior to the mid-1800's (funny it keeps coming back to this). Can you and Joeblow explain the results of Michelson and Morley without invoking an Aether. Do you really understand the significance of that experiment?


"How about this electricity and magnetism stuff. We can assume Maxwell is wrong, after all his theory led into Relativity."

Maxwell's equations assumed the existence of an aether
they haven't been changed so they still do

Please expain to this sophont where in Maxwells equations there are terms for an Aether.


"Mass, energy equivalenc forms a cornerstone of QM so we can throw out every thing we know about atoms, its based on Relativistic concepts."

E=mc² predates Einstein

Cite?


"What is charge?"

a property

What is time? What is energy? All wrong questions.

Not at all. They are questions physics grappled with in the 1800's and where partially answered by the likes of Einstein, Heinsenberg, Born, Lorentz et al.

If we are assuming these peoples theories are all wrong (as you are) you have to re-address the questions and come up with viable alternatives that also has to explain every experment ever done in the field since then.

Can you? If not, put up or shut up.


I think what you've just showed us is a complete lack of knowledge and understanding of what Einstein's theories stand for. It is much more about interpretation than naked facts. Dragging in technology is also irrelevant.

Oh. I don't think so.

The interconnectedness of Physics and technology is quite strong. The behaviour of transistors was calculated from Quantum Mechanics, those transistors and modern IC's are a testament to QM. QM has a built in assumption that Einstein was right. If we drop Einstein we drop QM. Which means IC's are built with a flawed theory hence they should not work.

GPS satellites have a relativistic correction built in. Atomic clocks use relativistic corrections.

As I suspect you will ignore all this or make it irrelevant please show me where I am wrong? Hard examples, not hand waving. Equations, proofs, that sort if thing.

The computer you are reading this on is a testament to the great work done in the early 1900's and alternative thinkers are simply sweeping it all away with out any knowledge of how things fit together.

Originally posted by Joeblow93132
thed,

I'll try to answer some of your questions, but I don't know everything either. What I do know is that Relativity DOES NOT make sense. There are more then one way to explain a phenomena and Einstein's way was wrong.

"So, first question is, what is light? Is it a particle or wave. Newton realised that shows properties of both."

Thank you for admitting that photons are particles. I guess since the main property of a particle is mass, a photon must have mass. There goes Einsteins theory about photons being PURE energy.

Your main assumption is wrong. The main property of particles is not mass. Frankly, physics is struggling to answer these two basic questions, what is mass? what are particles?

The Universe is truly a lot more complicated than we can realise. Simple assumptions like yours do not explain anything and completely ignore known facts.

Long and short of it is tha nothing with mass travels at light speed. As Xelios points out, a fact that is verified thousands of times daily in particle accelerators and the detection of cosmic rays.


"What does light travel in? If its an Aether that Aether exists every where. This means it must have zero density, otherwise you would feel it dragging on you. Assuming it carries waves it must have infinite elasticity, otherwise light would loose amplitude, quickly. Do you know any infinitely elastic but zero density materials? Actually, its an absurd idea so I'll wait for your answer."

Very foolish question. You assume that all matter must exert a drag on other matter.

See my response to C'est Moi for why this is decidely not a daft question.

Prior to Maxwell it was assumed that travelled in a medium that had mass. Maxwells equations show no medium is required. But they do not work with pre-Relativistic physics. If we throw out relativity we have to go back to basics. For starters, you have to throw out Maxwells equations as they conflict with Newtonian physics. Which leads to the questions of what are light, electricity and magnetism.

Friction and inertia always exists where there is matter acting on matter.


Does a superconductor exert a drag on the electrons traveling through it? Does the strength of the electron's electric or magnetic fields diminish with time as it travels in the superconductor?? I guess a superconductor must have "zero density and infinite elasticity""!!!(sarcasm).

Do you understand the difference between transmission of a wave and it's interaction with the medium through which it travels?

Granted heat is generated by electrons in a conductor being captured and subsequently escaping their shells. Work is done, energy generated and heat produced. A superconductor is where, at sufficiently low temperatures, electrons form cooper pairs and flow unimpeded. It's a QM effect. It has little to do with the transmission of EM waves.

My point, again missed, is that Relativity comes from kown problems with EM waves and Newtonian physics. Ignore one and you have to re-explain the other.


"How about this electricity and magnetism stuff. We can assume Maxwell is wrong, after all his theory led into Relativity. So what are they? Why does a moving magnetic/electric field create the other?"

Funny you should ask me. Wasn't it Einstein who completely ignored magnetic and electric fields. Answer this : What is Einsteins theory for the attractive and repulsive forces of electric and magnetic fields??Oops, he doesn't have one. He had a crazy theory about curved space but it ONLY applied to gravitational fields.

Guess what, Einstein was not out to explain electricity and magnetism. That had been done. And yes, he only had a theory about gravity. (If we ignore the mass of work in QM theory he conributed to). Your point was?

I'll say it again in case you are probably missing the very important point:

The theory of electromagnetics, the unification of electricity and magnetism led directly to Relativity. It lies at the heart of what the Universe is and fundamental concepts of space and time. Light and Relativity are closely intertwined. Ignore Relativity and we go back to the beginning and have to ask what is electricity, magnetism, light, how light propagates and atoms behave.

Can you? Can you make this work with only Newtonian Physics?


"How about atoms? Mass, energy equivalenc forms a cornerstone of QM so we can throw out every thing we know about atoms, its based on Relativistic concepts. Any ideas? What is matter made of? What is charge?"

Interesting that you should mention E=mc^2. As far as I know, most people don't even have a definition for energy. What is you're definition of energy?

Classic diversionary tatic, answer a question by asking one. I asked first, you answer.

If you don't know what energy is you are hardly in a position to reformulate Physics. My definition is the rate of force acting over time dF/dt. A force being the acceleration you feel when in the presence of some field, such as electromagnetism and gravity. Fundamentally, it is the rate of work done.


Try contacting a physicist who worked at Los Alamos in the 40's. Ask him/her what they thought about E=mc^2 after they detonated the first atom bomb? You'll be surprised!!

Non sequitor!

Heisenberg, working on the German bomb, got it totally wrong. What does that prove? Nothing. Only that people make mistakes. They had no idea of the efficiency of the bomb. Hint, it was not 100%.


"Hmmm, strange that Physics is so wrong yet it built an Atom bomb, radios, broadcast, silicon chips, predicted the cosmic microwave background, predicted the displacement of stars positions by the Sun, Black Holes, gravitational lenses etc"

I never claimed physics was wrong, I claimed Einstein was wrong. Unlike you, I don't believe that Einstein and physics are one and the same.

Tom [/B]

Funnily, I can see the differences but I can also see how one concept leads to another and provides further evidence or proof of a concept. Can you?

You can not formulate a theory of gravity without understanding the true nature of space, time and how light travels through it, first. To do this you need to first understand light and it's role.

From these beginnings you rapidly get into QM then statistical thermodynamics, Astrophysics, modern chemistry, wave propagation, cosmology and so on. It's funny how so many advances where made once a few fundamental questions where looked at. Something you seem you think can be blithely ignored.

"What about the differences in length of an object when travelling at different speeds? Is there a simple explanation for this as well?"

why don't you click with that mouse of yours on the link and read for yourself?

"What about the slowing of time just above a black hole's event horizon?"

may I remind you of the still hypothetical nature of black holes?
okay?

"The interconnectedness of Physics and technology is quite strong."

most technology in your house was invented by people who were considered being heretics
technology doesn't require explanation
if it works, it works

"If we drop Einstein we drop QM."

nope

"GPS satellites have a relativistic correction built in. Atomic clocks use relativistic corrections."

which as I said can be explained more easily

"E=mc² predates Einstein

Cite? "

study your history man
are you one of those guys whose also unaware that the background radiation was predicted already in 1926 by Eddington who believed in a STATIC universe (he calculated a value of 3.2 K)??

"What is charge?"

a property

What is time? What is energy? All wrong questions.

Not at all. They are questions physics grappled with in the 1800's and where partially answered by the likes of Einstein, Heinsenberg, Born, Lorentz et al."

you must truly be a genius, are we of the same world?
so you actually know WHAT time is, WHAT energy is (not what it DOES), etc.??

this man, is showing that you can't reason at all
further discussion with you will only lead to going through the same stuff again
you are seeing this in a whole different (wrong) way

did you check out marmet's paper?

Before this falls into ad hominens let me just say two things,

Cite. Give me the exact details of who derived E=mc^2 before Einstein as per your claim. Avoiding and changing the issue does not cut it. Details matter, I have not read every paper ever written unlike your venal claims to know the absolute truth.

Which part of 'partially explained' and the standard definition of energy did you not understand? funny is not, I give what I think is a reasonable explanation of energy, as asked, and all you can do is get sarcastic. Address the issues.

If I am so wrong tell me where I am wrong. Simply saying I am wrong, and telling the others they are wrong, is not good enough. Precisely what part of my argument is wrong. What do you propose that is better? If your best answer is; study history, you can't argue with this man or read the kooks web page coached sarcastically then don't bother answering. I want specifics, details, something tangible that can be verified. You claim to have a Ph.D. you know the ropes.

There are 4 things about the Spanish Inquisition.

"If you can't push an object to c because of it's mass, what about pulling it with gravity??

It wouldn't matter if you pushed or pulled, accelerating a massive particle to light speed requires infinite energy, which is why it can't be attained."


I was wondering if anyone might be able to answer this question: Can a blackhole or super blackhole accelerate an object to c?

As Xelios pointed out, the mass of the object would increase as it aproaches light speed. But according to Einstein, the gravitational field of the object would increase as well, so the force of the black hole on the object would also increase as the object gets faster and closer to the black hole. According to Einstein, the mass of the object would get larger until it is more massive then the black hole itself. The object would then actually swallow the black hole. Since this doesn't happen, I assume Einstein was wrong.

Any feedback would be appreciated.

Tom

The formula (derived from Pythagoras - and inconsistently assuming Euclidean geometry) is
estimated mass = m0/square root of (1-v2/c2)

The well-known series expansion approximation gives

estimated mass = m0 (1 + v2/c2/2) or

estimated mass.c2 = m0c2 + 1/2.m0v2

The expression 1/2.m0v2 is well known as the formula for kinetic energy; and it came to be accepted - following Poincaré, Burniston Brown says - that mc2 represented the 'potential energy' in some sense, since potential energy can be defined in terms of any starting-point. All this follows, for smallish v, only from the equation for the mass increase of an electron

It might also be interesting to know that technologists generating, or trying to generate, nuclear energy, think in terms of nuclear rearrangement and do not use the formula usually attributed to Einstein.

As for your definition of Energy ...:

"the rate of force acting over time dF/dt."

you have misdefined it
another popular one is "energy is the capacity to work"

these are obviously not identities! Well, energy can be changed in form and that is work. But energy is not the "capacity to change its own form", but is its own form, as can be seen.
so it turns out that your defention is not saying WHAT energy is, rather what it is known to do
is that so difficult to understand for you? apparently

let me present you an example which shows relativity is wrong:

Cosmologists have chosen to ignore the observations of two astronomers of Villanova University in Pennsylvania. Edward Guinan and Frank Maloney proved Einstein wrong by drawing attention to the measured the rate of perihelion motion of the two stars forming the double star system DI Herculis.

Einstein's theory required that their anomalous rate of advance of perihelion should be some 196 times faster than it is for planet Mercury. It was found to be only one seventh of the predicted amount for the classical and relativistic effects combined! Einstein's theory was wrong. A small additional component was also required from Newtonian gravitational theory, owing to the astrophysicist's assumption that the gaseous plasma constituting a star can be dragged by gravitational action of the other star in a binary pair.

In the event, it was found that the observed rate of perihelion advance was so small as to rule out any prospect of Einstein's theory being of any relevance, but, surprisingly, the plasma drag was not in evidence either. Now, what might that prove? Well, if you know anything about electric and gravitational potentials in stars being in balance, you should understand that the action between matter in two stars in a binary system will conform with the same principle. In other words, there can be no gravitational drag effect adding to the perihelion advance. There can be no gravitational 'tide' effects if the star has a uniform mass density. In that context it reacts as if it were a homogeneous solid.

The Guinan and Maloney observations, can be found on p. 23 of the August 29, 1985 issue of New Scientist.
have a good read

Originally posted by c'est moi
[B]The formula (derived from Pythagoras - and inconsistently assuming Euclidean geometry) is
estimated mass = m0/square root of (1-v2/c2)

The well-known series expansion approximation gives

estimated mass = m0 (1 + v2/c2/2) or

estimated mass.c2 = m0c2 + 1/2.m0v2

I seem to get a different answer,

estimated mass = em = m0 (1 + v2/c2/2)

hence, em = m0 (1+2*v2/c2)

or, em = m0 + m0 *2 * v2 / c2

=> em * c2 = m0* c2 + 2*m0

----------------------------------------------------------------------------------

SPOT THE ERROR

em * c2 = m0* c2 + 2*m0*v2

-----------------------------------------------------------------------------------


But anyway, you have still not answered the very direct questions I am asking. Where am I wrong? You keep changing direction and dragging up different points to shift the direction of this argument. It was claimed Einstein was wrong and I posted a rebbutal of the point. No one has yet to address that.


==============================================

Edited to add a SPOT THE ERROR

==============================================

Originally posted by Joeblow93132
"If you can't push an object to c because of it's mass, what about pulling it with gravity??

It wouldn't matter if you pushed or pulled, accelerating a massive particle to light speed requires infinite energy, which is why it can't be attained."


I was wondering if anyone might be able to answer this question: Can a blackhole or super blackhole accelerate an object to c?

As Xelios pointed out, the mass of the object would increase as it aproaches light speed. But according to Einstein, the gravitational field of the object would increase as well, so the force of the black hole on the object would also increase as the object gets faster and closer to the black hole. According to Einstein, the mass of the object would get larger until it is more massive then the black hole itself. The object would then actually swallow the black hole. Since this doesn't happen, I assume Einstein was wrong.

Any feedback would be appreciated.

Tom

Some one got this wrong. Your relativistic mass, to use the older term, increases. This does not mean your gravitational field increases.

Think of it this way, by a simple question, how fast are we travelling?

With respect to a distant galaxy we are travelling near light speed, so we are a black hole already. This is an obvious absurdity.

The point is that all things are relative.

Some one got this wrong. Your relativistic mass, to use the older term, increases. This does not mean your gravitational field increases.

Think of it this way, by a simple question, how fast are we travelling?

With respect to a distant galaxy we are travelling near light speed, so we are a black hole already. This is an obvious absurdity.

The point is that all things are relative.

Also, the gravitational force of an object depends on it's mass and distance. An object entering a black hole could not exceed the black hole's mass because in order for this to happen the black hole would need a larger gravitational pull than it's mass would allow. Much like absolute zero can't be reached because there is nothing colder than it to absorb energy from an object.

You also seem to forget, Tom, that as the mass of a black hole increases so does the size of it's event horizon. The object would probably be inside the event horizon before it could accelerate to c (which isn't possible anyway).

may I remind you of the still hypothetical nature of black holes?
okay?

Yes, black holes are still for the most part hypothetical. However, the effects of gravity on time are not. Can you answer the question?

The Guinan and Maloney observations, can be found on p. 23 of the August 29, 1985 issue of New Scientist.
have a good read

Have these observations been tried by other scientists in different parts of the world? Have they been reproducable at all? If you are trying to disprove a theory that has given accurate and detailed results to many problems plaguing physics this century with a single observation made by two scientists 17 years ago I'd have to ask you to try a little harder.

"hence, em = m0 (1+2*v2/c2) "

this step is wrong, can't put the 2 overthere just like that

(it's: v2/c2)
-------
2

anyway, have you read the above? direct proof against general relativity
further you have those so-called "paradoxes" (for example the clock paradox where relativity principle is in dispute with the Lorentz transformations) which are not paradoxes at all but real problems

let me explain one of them:
this time it is in statics: there is this lever with two equal arms at right angles and pivoted at the corner. It is kept in equilibrium by two equal forces producing equal and opposite couples. according to the Lorentz transformation equations referred to a system moving with respect to the lever system, the couples are no longer equal so the lever should be seen to rotate, which is, of course, absurd. Tolman tried to overcome this by saying that there was a flow of energy entering one lever arm and passing out through the pivot, just stopping the rotation! Overlooking the fact that energy is a metrical term and not anything physical there would presumably be some heating in the process which is not considered. Statics provides insuperable difficulties for the physical interpretation of Lorentz transformation equations and this part of mechanics is avoided in the textbooks – in fact, Einstein omits statics in his definition: “The purpose of mechanics is to describe how bodies change their position in space with time”

i'm not avoiding anything, you rather are
you're not even willing to read a paper which is available on the web concerning special relativity
i would understand it if it was in some scientific magazine which you gotta go and search in a library at a uni, but all you have to do is click with your mouse on the link
if wanna go search an article, search for this one: What is wrong with relativity by G. Burniston Brown in the BULLETIN of The Institute of Physics and the Physical Society, pp. 71-77, March 1967

the question is: would you be ready to accept any evidence against it? or have you last your heart to relativity? - Special Relativity is like smoking, no one likes it at first, is starts because of peer pressure, it is addictive, it is bad for you, and it is very hard to quit once you start

as for what should replace relativity I have no idea
Marmet seems to be able to explain a whole lot of things with newtonian physics and quantum physics alone
maybe it should be autodynamics
http://www.autodynamics.org
whatever it is that we humans say, nature will never reveal all her secrets
we are always bounded to our perceptions
we can never be sure of anything

I am not "addicted" to relativity. However I will not change my mind about one of the most important theories to have been discovered in physics because a few people think the idea of curved space is silly. If you present hard evidence that disproves relativity I will have no problem reassessing my views, until then relativity continues to provide accurate and correct answers to many problems in physics and conforms to the vast majority of observations. To claim it is completely wrong is extraordinary, and extraordinary claims require extraordinary proofs.

"However I will not change my mind about one of the most important theories to have been discovered in physics because a few people think the idea of curved space is silly."

i think i have said more than that
the rest of what you say speaks for itself
(and address the specific issues that i have raised)

"Have these observations been tried by other scientists in different parts of the world? Have they been reproducable at all? If you are trying to disprove a theory that has given accurate and detailed results to many problems plaguing physics this century with a single observation made by two scientists 17 years ago I'd have to ask you to try a little harder."

do you think i am aware of all the observations over the past years? i happen to know about this one
there might be more
have heard many times that "all there needs to be is ONE experiment that contradicts relativity ... "
what is this?
oh and observations are not "reproduced", they are confirmed and it seems to me that New scientist is a good and reliable magazine, i have NO reason to believe that it is a wrong observation
peer-review is succesfull in eleminating doubtful stuff
if this is your answer, then consider it poor
besides, as said before, these paradoxes in relativity are fundamental problems, they're not paradoxes at all

have heard many times that "all there needs to be is ONE experiment that contradicts relativity ... "
what is this?

That one experiment must be accurate and the results must be reproducable by different scientists in different facilities at different times. You can't make one observation one time and claim it disproves a theory.

oh and observations are not "reproduced", they are confirmed and it seems to me that New scientist is a good and reliable magazine, i have NO reason to believe that it is a wrong observation

Did you hear about the scientists that reported finding element number 116? The find was documented in several key scientific magazines, and they were respected scientists. As it turns out they made an oops and couldn't reproduce the results, so they withdrew their claim. Can I expect the same here?

if this is your answer, then consider it poor

I'm sorry, I believe you will soon find out that insulting people's arguements will get you nowhere.

the rest of what you say speaks for itself
(and address the specific issues that i have raised)

How so?

i think i have said more than that

Yes, I'm sorry, you did provide one piece of evidence to support your arguements. However, the validity of this evidence is doubtful at best until the experiment is repeated several times by several different scientific facilities and found to conform to the original claim.

I'd just like to point something out briefly. Many people mention the discrepancies in GP Satellites as proof of time distortion or whatever. Maybe it is, I don't know. But just in case you don't know, those satellites vary in their orbits; that's why there are discrepancies and adjustments.

Good point Adam :)

There have still been seperate experiments done using extremely accurate clocks and they also showed a differance in time when travelling at different speeds and at different distances from Earth.

Those clocks work on atomic decay. An electromagnetic phenomenon. EM phenomena interact with each other. Rates of decay may vary between Earth's surface and in space. Or maybe not. I think thee has not yet been enough space-based research into that question. That alone may be responsible for discrepancies between atomic clocks on the ground and the mirror clocls sent into space. Different EM fields and interactions. Or it may not. Either way, I would like to see that researched more fully before people arbitrarily declare it is time travel or some such.

for the clocks: When atoms are accelerated, the increase of kinetic energy increases the electron mass, which makes the Bohr radius larger
and well this increase of radius produces a shift in the atomic energy levels and also an increase of the physical size of matter. Consequently, a moving atomic clock now runs at a different rate.

another experimental proof against relativity is the Sagnac's experiment
Sagnac effect was published in 1914 in which it has been shown experimentally that light takes a longer time to go around the world Eastward than Westward. The Sagnac effect is well known and It has been added in the Global Positioning System (GPS) to determine time and coordinates on Earth. The Sagnac effect is also used in optical gyroscopes. It is very well extablished. the effect shouldn't be there according to relativity prinicple


another paper you might want to look for is this one:
Héctor Múnera. 1998. Michelson-Morley Experiment Revisited:
Systematic Errors, Consistency Among Different Experiments
and Compatibility with Absolute Space. Apeiron 5, 37-54

He shows that the analysis of these data reveals that, contrary to a general belief, the Michelson-Morley experiment does not give a null result.

lenght contraction can also be caused by gravity
these are all REAL natural effects
it has nothing to do with slowing down of time etc.
makes it less exciting, but that's science
relativity contradicts even reality in this:

Einstein's length contraction implies that the Bohr atom gets smaller
however, quantum mechanics shows that such a contraction of the Bohr radius should increase the atomic energy levels. This consequence of Einstein's predictions is contrary to observational facts which show that at high velocity, the atomic energy levels become smaller and the atomic clocks get slower!!

besides, who ever said that clocks measure time? you gotta be an idiot to think that!

I can't believe how everyone is still claiming that time slows down as objects approach light speed. As I mentioned in a previous post, is it possible that time is constant and the reactions slow down?

As I indicated before, catalysts speed up chemical reactions. If Einstein was observing that chemical reaction with a catalyst, would he say that the catalyst is speeding up time?

It's funny that every day we can observe hundreds of reactions that speed up and slow down, and all these reactions can be explained using classical physics. Where would mankind be if instead of trying to find out why those reactions speed up or slow down, we were to say that time speeds up or slows down?


Unfortunately, no one has answered my black hole problem. First, let me say that super black holes are no longer theoretical. It has been found that the stars close to the center of the galaxy are moving so quickly, that the object they are orbiting around is so massive it qualifies as a blackhole. So I will ask again, If you have an object, like a planet, about 100 billion miles away from a super blackhole, wouldn't the blackhole accelerate the planet to c before the planet enters the blackhole's event horizon?

Tom

"If people want to dismiss Einsteins Relativity they have to first start with disproving the equivalence principle (gravity and acceleration are the same) then the rest of the argument."

the priniciple is wrong

consider a mass standing on the surface of the Earth
After one year, the mass submitted to gravitational acceleration is always standing there, without changing its energy or velocity. Another identical mass is submitted to an inertial acceleration of one G in outer space by a rocket. After one year, the energy given to the mass is such that its velocity has reached an important fraction of the velocity of light. An enormous amount of energy has to be given up to the accelerated mass in order to produce such a continuous acceleration. When that last mass falls on Earth its energy would produce a gigantic crater on the impact.
einstein's theory claims that these two phenomena are equivalent and undistinguishable. The difference can be seen very easily. In order to convince people, Einstein adds that there is no difference for the observer located in the moving frame of reference.

The principle of equivalence between inertial and gravitational mass which ignores that the energy has been given up to the mass is bad science!

C'est Moi: Would that Sagnac difference not be due simply to the fact that the point of transmission/reception has moved? If I tell someone standing beside me on the athletics track to run around the field until he reaches me again, but I move forward ten metres along the track, it will take longer to reach me than if I had remained where I was. The Earth revolves. The point of transmission/reception moves. The signal does not share a common velocity with Earth, thus it is like the athlete running around trying to catch up. I'm not saying that's what it is. Just asking if that's what it might be.

what you say is correct, and that's just the point: That difference of time for light taken between each direction depends directly on the velocity of the Earth moving around itself.
BUT Einstein's Theory claims that there is no possible way to detect the ABSOLUTE velocity of the Earth. The very use of the expression RELATIVITY comes from Einstein's hypothesis that parameters, like VELOCITY, are relative so that any absolute motion (like absolute velocity) is meaningless. However the velocity of Earth is responsible for the change of time light takes to go around the Earth. From a fixed location on Earth, we can detect the Earth's motion. Therefore, contrary to Einstein principle of relativity, the velocity of light is not relative to the observer. One must conclude that the Sagnac effect contradicts Einstein's hypothesis of General Relativity.

wouldn't the blackhole accelerate the planet to c before the planet enters the blackhole's event horizon?

Once again, no. That would require an infinite amount of energy, which is the same reason why particles can be accelerated to 99.99% of c in an accelerator but never quite over it.

Xelios,

Again I ask you: If an object is moving at 99.99 percent of c towards a blackhole, can the balckhole accelerate the object to 99.999 of c? And if the object is moving towards a blackhole at 99.999 of c, won't the blackhole accelerate it to 99.9999 of c?

I hope you understand my point. Regardless of how fast the object is moving or the current "relativistic" mass of the object, the blackhole will continue to pull.

And if the gravitational field of the object increases with it's mass(which you deny), won't the increased gravitational force compensate for the increased mass of the object?

Tom

Joeblow,

"... gravitational field of the object increases with it's mass(which you deny), won't the increased gravitational force compensate for the increased mass of the object? "

he denies this because the principle of equivalence of einstein refutes this
but as I have showed, the principle is not correct
acceleration by gravity is not the same as acceleration per inertia
there is an increase in mass
the principle of mass-energy conservation is ALWAYS valid

c'est moi,

To pick two examples at random:

First: <i>Edward Guinan and Frank Maloney proved Einstein wrong...</i>

Has this work been independently verified? If so, reference please. If not, why not?

Second: The Sagnac effect does not contradict relativity, to my knowledge. There is much literature on geometrical or Berry phases which you may want to look at.

"To pick two examples at random:"

thank you very much ..

"Edward Guinan and Frank Maloney proved Einstein wrong..

Has this work been independently verified? If so, reference please. If not, why not?"

maybe you want to look that up, i have no idea, you can look up the article or try to contact the two scientists no?

"Second: The Sagnac effect does not contradict relativity, to my knowledge. There is much literature on geometrical or Berry phases which you may want to look at."

on the contrary, it does as i have already explained (unlike you, you just say it doesn't and period)

Joeblow, I fail to see your point. If the object is accelerated to 99.99% the speed of light it will continue to travel toward the black hole no matter what it's relativistic mass. This is called inertia. Indeed as soon as the object falls into the black hole's curvature it will continue moving toward it until something interferes externally. As the curvature gets steeper (nearer the black hole's center) the object travels ever faster toward it.

Hope that answeres your question. I would stay longer, but I've caught a bad flu this weekend so I'm going to bed (even had to cancel my ski trip to the Rockies :( ).

What does "rest mass" mean?

Xelios, get well soon!

"rest mass" --> mass at rest!

then what is "mass at rest"?

Rest mass is the mass an object has when it's not moving. For example, when you step on a scale that is your rest weight (which is just mass * 9.81) (well, almost rest mass, you are still moving along with the Earth). Relative mass is the aparent mass an object has when it's moving. The faster the object moves, the more mass it has. This is why photons can travel at light speed, they have no rest mass, but they do have relative mass. If a photon were to stop (which doesn't happen), it would simply disappear because it would no longer have any mass.

Xelios, get well soon!

Thanks :) The teachers here are going on strike for as long as 7 weeks starting Monday, plenty of time to get well I guess :p

Bad thing is I have a diploma exam in Math 30 Pure this semester, 7 weeks of missed school could really screw that up :(

I heard only a couple of months ago of an experiment in which a pulse of light was stopped on its way through a chamber through the use of a laser, then it was allowed to keep going again. Does that count as photons being stopped?

In a way. But the focus of that experiment was on capturing the photon's "information" and then recreating another identical photon from that information. They didn't exactly stop a photon, but they did succeed in storing the information it contained and then replicating an exact copy of it. Interesting applications to computers I would think :)

c'est moi:

"Despite the ease and clarity with which special relativity accounts for the Sagnac effect, people who lack a sound grasp of basic physics and mathematics sometimes imagine that this effect entails a conflict with the principles of special relativity."

That is an extract from the following site:

<a href="http://www.mathpages.com/rr/s2-07/2-07.htm" target=_blank">http://www.mathpages.com/rr/s2-07/2-07.htm</a>

If you do a search you will find many such pages.

The Sagnac effect is entirely compatible with and explained by special relativity.

I have no problem, I can't deny anything about SR since I know very little about it. But I have seen no reason in any of this for people to even consider the possible existence of time travel or time dilation. The Sagnac effect is a plain old physical mechanical property. You go round in one way, it takes you longer to reach the starting point because that point is moving. There's no time trickiness going on there at all. It's a very ordinary mechanical effect.

Here is another question though. If a light pulse going around one way takes long enough for it to become 360 behind the phase of the other pulse, and they meet up again precisely in phase (except one is one cycle behind the other), how is the difference detected? Can it be detected at all, or do we just assume from the distance covered that it is one cycle behind?

god, it's been just a few days a posted this thread and it's already on page 6... uf! (haven't had the time to read it all yet)


Originally posted by Crisp
Lua,
Neutrino's have been proven to have mass. Check out the results on the Superkamiokande detector in Japan (a google search should do the trick). Also, energy does not always equal mass; the formula E = mc² you are referring to is only valid if the object you are studying is at rest. For moving objects (such as photons) the full formula reads:

E² = (m₀c²)² + (pc)²

Here m₀ denotes the rest mass, p the momentum. Substituting m₀ = 0 in this formula yields:

E = pc

Or: for a photon the energy is contained completely in its momentum. I should add that for photons the momentum p is not the classical formula p = mv ;).
[/B]

hey crisp,

for "rest" do you mean inercia? if you do, wouldn't a photon be in a constant velocity (moviment) in the vaccum of the universe, therefore in some kind of inercia (so you can use the e=mc2 formula)? i'm sorry, i'm just starting in this, so if i said some bs please correct me. wouldn't "movement" be only when the particle is in a accelerated moviment?

also, i was thinking, as mass becomes more energy as much as it gets near to the velocity of light (according, again, to einstein), wouldn't the reason for the lack of a photon mass be exactly that: all its mass is in all its energy state since it travels in light's velocity in the vaccum? that doesn't mean it doesn't have mass, but that the mass presents itself in the energy "mode".

i don't knoe if i could explain it right... english is not my first language anyway...

Hi Lua,

"for "rest" do you mean inertia? if you do, wouldn't a photon be in a constant velocity (movement) in the vaccum of the universe, therefore in some kind of inertia (so you can use the e=mc2 formula)? i'm sorry, i'm just starting in this, so if i said some bs please correct me. wouldn't "movement" be only when the particle is in a accelerated movement?"

With "rest" I mean that for you, as an observer, the particle has a velocity of v = 0. It does not move at all.

"Also, i was thinking, as mass becomes more energy as much as it gets near to the velocity of light (according, again, to einstein), wouldn't the reason for the lack of a photon mass be exactly that: all its mass is in all its energy state since it travels in light's velocity in the vaccum? that doesn't mean it doesn't have mass, but that the mass presents itself in the energy "mode"."

Hrmmmm... your first sentence isn't entirely correct. Mass does not become more energy as speed increases. there's no "conversion" going on. You have to be careful about the word mass (that's one reason why I have always argued to use the words "rest mass" and "relativistic mass" instead of just mass ;)). When looking at the energy of a particle, there are two contributing terms, as you can see in the formula I stated above:

- There's a term that is related to the rest mass (m₀c²)²
- There's a term related to the momentum (pc²).

For a particle with rest mass, this means that the minimum energy that particle can have is E = m₀c² (that is when the particle is at rest, v = 0, which for particles with mass comes down to p = 0). As the velocity (and hence p) increases, the particle just gets more energy, but the rest mass is unaltered.

You can also look at a thing called "relativistic mass" (which is briefly called "mass" when talking about the theory of relativity). This quantity is only definied for particles that have a rest mass. The (relativistic) mass can be deduced from the energy as follows:

E = mc² (only for particles with a rest-mass!!!)

Where m = m₀ / sqrt( 1 - (v/c)²). You can easily deduce this formula yourself by inserting p = m₀v / sqrt( 1 - (v/c)² (which is also only valid for particles with restmass) in the E² formula you quoted above. So in a way you are right: the "mass" m deduced from the energy-mass equivalence relation above increases as the energy increases - and the only way for the energy to increase for a particle with restmass is for it to move faster (so at higher speeds, relativistic mass consists more of energy due to motion than of energy due to restmass). This however does not apply to photons which only source of energy is its momentum (cfr. quantummechanics, special relativity).

Hope this explains it somehow ;)

Bye!

Crisp

"The Sagnac effect is entirely compatible with and explained by special relativity."

I have read the link. The argument he cites (and disproofs) is not exactly the one I have given. Please just say where I go wrong. According to what I know, trying to detect ABSOLUTE velocity is needless viewed from the principle of relativity, hence the very name "relativity". But because of the Sagnac effect, which I agree, anyone can understand, we do detect the absolute velocity of rotation of the earth.
Just tell me why this is compatible with relativity.

c'est moi,

The Sagnac effect is not detecting an absolute velocity. It arises because the apparatus is rotating. The principle of relativity says the laws of physics are the same in all inertial frames of reference. A rotating frame is non-inertial, so the Sagnac effect does not conflict with relativity.

Originally posted by Crisp

thanks crisp, i did understand that. :)
i just always read books using the e=mc2 formula for all objects including those on movement. i guess when you try to simplify mathematics something comes wrong.
i'm soon starting my phisycs college, so i probably get those concepts right again later, i was just being curious.

take care.

"The Sagnac effect is not detecting an absolute velocity. "

because of the Sagnac effect, we can caculate the velocity of the moving observer ( = velocity of the earth) which is the Absolute velocity
why would this be a relative velocity???

might be helpful in regard to the sagnac effect:
http://www.ldolphin.org/sagnac.html

lots of stuff concerning special relativity (but also papers on general r.)
http://www3.sympatico.ca/wbabin/paper/index.htm

the look of a philosopher on relativity and quantum physics:
http://www.geocities.com/Athens/Atrium/8041/

and let it be said: Most scientists are terrible philosophers, a MAJOR problem as discussing stuff like relativity is BASED on philosophical appraoches etc. and not firstly on Experiments as most think

Groovy links C'est Moi.

Now, I've only started reading on special relativity and all that, but so far it seems a lot simpler than I had expected. As yet, I don't see any big deal about it. All very straightforward.

Velocity of EM waves/emissions is a constant divided by the material it is passing through. That's no problem. My fastest running rate is slower if I'm in water, for an analogy. So at the very start it is a very basic mechanical idea.

Now if I'm running along in water for example, my speed will be the same regardless of whether any observers are flying by in an aircraft or sititng there have a drink on the beach. Motion of observers makes no difference. Again, nothing more than a very obvious mechanical idea.

Same for light in both cases. If I'm shot out of a torch which is in that aircraft, or if the torch is on the beach having a drink, I can still only run at that certain speed in the water. Maybe if I'm shot into the water eXtremely fast, I may enter the water at very great speed, but that will almost instantly be transferred into force against me and splashing and such. I'll still be left running through the water at the same speed as usual.

These three analogies seem to me to represent the core of relativity as I understand it so far. I see no disparity with basic mechanics. There is nothing there which Newton would have a fit over.

What exactly are the supposed problems with relativity? Could someone explain to me in simple terms any problems they see with it all?

Adam,

No, this subject is unlike you say VERY complicated. Many times it has been said that nobody really understands relativity, and these scientists didn't say it just like that.

<<What exactly are the supposed problems with relativity? Could someone explain to me in simple terms any problems they see with it all? <<

the problem starts: it is quite impossible in simple terms, it gets complicated very quickly!
when i have the time, i'm gonna do some new research and write a piece on that
i'll give you the link then

@ James r:

Explain why you think "a rotating frame is non-inertial".

Explain why you think "a rotating frame is non-inertial".

Imagine a small cart moving at constant velocity and spraying paint dots passes in front of a wheel rotating at constant angular velocity. The paint dots on the white rectangle placed to the left of the wheel record the motion of the cart as seen by an observer; the dots on the wheel describe the motion of the cart as seen by an observer at the center of the wheel and rotating with it. Standing on the ground in our reference frame, we see that the cart is subject only to forces which we can ascribe to specific objects in the environment, i.e. the drive, friction, etc. We call this frame an inertial reference frame. To an observer on the wheel, however, the cart must be subject to some additional force since both the direction and the magnitude of its velocity change. We call the rotating frame a non-inertial reference frame because we must postulate pseudo forces (sometimes called inertial forces) to account for the motion of the cart in this system.*

Very nifty analogy.

I suspect it is all going to end up being quite easy. Most things are in the end. I suspect many people simply get caught up in the maths and fail to see basic principles. But then, I have yet to learn it all, so feel free to deliver words of impending doom for my future studies.

Using the Sagnac effect you can only calculate the angulr rotational velocity of the apparatus relative to a particular local inertial frame. You cannot calculate any absolute velocity, and in fact, if you use the Lorentz transformations to look at a different inertial frame (with a different velocity), the Sagnac effect remains the same.

Originally posted by James R
Using the Sagnac effect you can only calculate the angulr rotational velocity of the apparatus relative to a particular local inertial frame. You cannot calculate any absolute velocity

let's take a look at that again:

the velocity of the observer on earth can be calculated with the Sagnac effect with following equation:

v = c - V

where 'v' is the MEASURED velocity of light and 'V' the velocity of the observer (and this also the velocity of the rotation of the earth) --> the observer can simply be considered as a marked point on earth

this agrees with the results expected from an absolute frame of reference, in which light is traveling at velocity c with respect to a fixed frame at rest.
for a circular trajectory, the measured velocity of light is not "c" but "v", in the frame of reference used by the observer moving with the disk. The velocity of light v is equal to (c-V) or (c+V) depending on the relative direction of V with respect to c

if you say we have calculated a Relative velocity "V", then what is the local inertial frame in this specific example?
is it the universe that is turning and not the earth?

c'est moi:

Bear in mind that the speed of light measured by an inertial observer outside the Sagnac apparatus <i>or</i> in an inertial frame co-moving with a particular point on the rotating apparatus is the same. Light travels at a constant speed in all inertial frames. There are no absolute frames of reference.


Adam,

Relativity is somewhat more complex than you currently think. You said:

<i>Now if I'm running along in water for example, my speed will be the same regardless of whether any observers are flying by in an aircraft or sititng there have a drink on the beach. Motion of observers makes no difference.</i>

That's wrong. If you are running along at 1 metre per second as seen by somebody sitting on the beach, and a plane flies past you (in the opposite direction) at 100 metres per second, your speed as seen by the pilot of the plane will be 101 metres per second. The motion of the observer clearly makes a difference in this case. However, if you shine a torch light in front of you, the person on the beach will see it travel at speed c metres per second. You might expect that the pilot of the plane will see the light travelling at c+100 metres per second, but that's not what happens. Actually, the pilot <i>also</i> sees the light going at c. That is a very counter-intuitive idea once you understand it.

<i>There is nothing there which Newton would have a fit over.</i>

There is much in relativity that shows that Newton had things right for low speeds, but completely wrong for speeds approaching the speed of light.

<i>What exactly are the supposed problems with relativity?</i>

There aren't any, as far as we can tell. Countless experiments have shown relativity to be correct and Newton to be wrong.

There are some niggling problems with producing a quantum theory of gravity, but quantum theories already incorporate special relativity.

c'est moi:

I looked at your links.

With the first one, alarm bells started ringing as soon as I read the qualification of the author (from the "Association for Biblical Astronomy"). It then goes on to quote a 1938 paper for the supposed incompatibility of the effect with relativity. (Nothing more recent?) While I haven't read that paper, from the quoted sections of it it does not seem to support the author's conclusions. Besides, the problem pointed out is addressed in the link I gave earlier.

I haven't read Babin's paper in full, but reading the conclusion is sufficient to show that he does not understand special relativity, because he refers to a "universal reference frame" or similar defined by the speed of light.

Lindner (MD) seems to be more concerned with philosophy more than physics. (Does he have any physics training?) While I agree with your point that relativity is based on some axioms which could be considered a kind of philosophy, the veracity of those axioms is supported by an enormous body of experimental and observational evidence. Thus, relativity cannot be considered to be a philosophical construct. It is solid science.

JamesR:

"C is a constant regardless of frame of reference." I believe that is what people have been telling me. The water thing is an analogy. Looks like what that means is that regardless of your own motion *relative* to the light/runner, the light/runner is still only moving at a certain absolute velocity. The *relative* velocity depends on the motion of the observer. But the light/runner is still moving at the same velocity as always. Or so it seems to me.

Adam,

According to relativity, there <i>are</i> no absolute velocities. All velocities are relative.

A rotating frame is non-inertial because it doesnt follow Newtons law that says that only when a force is applied an acceleration will be produced in direction of force application.

now acceleration is a vector.since while rotating acceleration changes constantly,(because of it direction changed) without any force instantaneously being applied,thus a non-inertial frame.

A pseudo force called centri-fugal force is assumed to have been applied to make the frame inertial,in order to tackle the problems .

if i am wrong James kindly rectify me...


bye!

"With the first one, alarm bells started ringing as soon as I read the qualification of the author (from the "Association for Biblical Astronomy"). It then goes on to quote a 1938 paper for the supposed incompatibility of the effect with relativity. (Nothing more recent?) ........................."

i didn't read it myself
just quickly looked, saw Ph.D (not the Association for Biblical Astronomy) --> bad link, sorry

"I haven't read Babin's paper in full, but reading the conclusion is sufficient to show that he does not understand special relativity, because he refers to a "universal reference frame" or similar defined by the speed of light."

i know
but there're quite a lot of submitted papers to read
had just a quick look myself
just found that link myself

"Lindner (MD) seems to be more concerned with philosophy more than physics. (Does he have any physics training?) While I agree with your point that relativity is based on some axioms which could be considered a kind of philosophy, the veracity of those axioms is supported by an enormous body of experimental and observational evidence. Thus, relativity cannot be considered to be a philosophical construct. It is solid science."

there is the possibility at the university to study Physics without any maths and is mainly concerned with the philosophical implications etc. I think it is called 'metaphysics'
when you hear of debates between physicians and philosophers, then it is about that kind of philosophers
and they NEVER agree in debates, both say of each other that the other side just doesn't understand it! (the recent debate on Time for example)
If you want my opinion, it is the philosophers who understand the matter better: philosophy is the basis of physics
physicians tend to think that they can be an objective observer, conducting experiments, reading the data, confirming it, etc. all without philosophical implications --> this is absolutely wrong: otherwise there wouldn't be any discussion going on in any science field
philosophy is primary, not physics

now, when you say Solid science I will have to interrupt you
it's true: E = mc² is great formula and is correct
but what about decay processes: they had to postulate a new neutral particle "neutrino" because the observed amount of energy output was not in accordance with Special relativity
now, afterwards, they claim the neutrino has been found
and that is still very much open to debate unlike many would like to have it

also, the principle of equivalence which is ABSOLUTELY vital for BOTH special and general relativity is according to me not at all correct and I gave a simple example (to which no one responded) previously to explain why I think this is so --> mass-energy conservation is ALWAYS valid, also for gravitational acceleration!!!
also, the Lorentz equation are mathematical correct but not PHYSICALLY! (see Carezani at http://www.autodynamics.org )

lastly, relativity explains phenomena with things like "time dilation", "length contraction" etc. (because of Lorentz transformations) which simply do not feel like the BEST explanation to me, and when you find that people like Marmet explain this easily with De Broglie equations, etc. then these extroadinary claims of relativity are utterly useless
I find it also incredible that so many clever scientists out there erronously believe that time is what a clock displays .. A clock does not measure time!! when such people read data from a clock and from that derive that time must have slowed down then I wonder where their sense of reason is.

"Bear in mind that the speed of light measured by an inertial observer outside the Sagnac apparatus or in an inertial frame co-moving with a particular point on the rotating apparatus is the same."

but the MEASURED speed of light IS different as the formula easily proofs
it doesn't matter what the real speed is
the measured speed is still different
and the measured speed of an observer outside the rotation will measure a different speed (just c normally)
so your claim is easily proofed wrong
you should have said that the speed is always the same
not the MEASURED speed

BUT i ask again: if you say we have calculated a Relative velocity "V", then what is the local inertial frame in this specific example?
I would like to know of which one you are thinking and I am not talking about an apparatus but about the earth here

"There are no absolute frames of reference."

according to relativity that is

Originally posted by zion
A rotating frame is non-inertial because it doesnt follow Newtons law that says that only when a force is applied an acceleration will be produced in direction of force application.

now acceleration is a vector.since while rotating acceleration changes constantly,(because of it direction changed) without any force instantaneously being applied,thus a non-inertial frame.

A pseudo force called centri-fugal force is assumed to have been applied to make the frame inertial,in order to tackle the problems .

if i am wrong James kindly rectify me...


bye!

Just a question: which force makes the earth rotate on its axis ???? and if there's no force doing that, what is the cause ...

c'est moi,

Thanks for your post. I am glad you didn't dig in and assert that the three sites you linked about were gospel, which you could easily have done, forcing me to go to extra effort to show them wrong.

Metaphysics is concerned largely with the basis of being - what it means for things to exist, why there is something rather than nothing, what we can be sure is real - that sort of thing. Those questions are technically outside the scope of science. I'm not saying that they are not worth asking. I agree that philosophy is an important discipline in its own right. Science is more concerned with describing how things work than explaining the true underlying nature of things; that is a job for metaphysics. Thus, science has a good description of time, but cannot explain things like why time exists in the first place.

<i>If you want my opinion, it is the philosophers who understand the matter better: philosophy is the basis of physics</i>

As I said, I think they deal with different things. Many philosophers don't understand physics. Many physicists don't know much philosophy. Some people in both disciplines have a good knowledge of both.

Let's look at some of your science issues, which I can provide some definite answers to (there are no definite answers in philosophy):

<i>E = mc² is great formula and is correct but what about decay processes: they had to postulate a new neutral particle "neutrino" because the observed amount of energy output was not in accordance with Special relativity
now, afterwards, they claim the neutrino has been found
and that is still very much open to debate unlike many would like to have it</i>

The existence of the neutrino was postulated on the grounds of energy and momentum conservation issues in various nuclear processes. Energy and momentum conservation are fundamental concepts of physics. The problems raised could be fixed in two ways - throw away energy and momentum conservation OR postulate a new particle. Much less "damage" came from postulating a new particle. Countless subsequent experiments have tended to confirm the existence of the neutrino. I am interested to know why you think its existence is still an open question.

<i>also, the principle of equivalence which is ABSOLUTELY vital for BOTH special and general relativity is according to me not at all correct</i>

Yet no experiment has contradicted it (despite certain claims you may see strewn around the internet).

<i>the Lorentz equation are mathematical correct but not PHYSICALLY!</i>

Autodynamics has been refuted by others, so I won't get into that here.

<i>lastly, relativity explains phenomena with things like "time dilation", "length contraction" etc. (because of Lorentz transformations) which simply do not feel like the BEST explanation to me</i>

Much of physics is counter-intuitive. I personally find quantum mechanics much more bizarre than relativity. But history has shown (in physics at least) that common sense is no guide to a good scientific theory. We must be led by the evidence.

<i>...and when you find that people like Marmet explain this easily with De Broglie equations, etc. then these extroadinary claims of relativity are utterly useless</i>

At some stage, I will probably have to critique Marmet in detail. Unfortunately, there is a lot of information there and I have limited time. Suffice it to say that I have serious doubts about the correctness of Marmet's theories, but I admit I have not looked at them in detail yet. If they were sound, why have they not been published in peer-reviewed journals?

<i>I find it also incredible that so many clever scientists out there erronously believe that time is what a clock displays...</i>

They don't. When relativists say "clock" they mean "any device which can measure time". That includes you pulse, your digital watch, a swinging pendulum, the rate at which you age, your heart rate, and so on.

Regarding the Sagnac effect: the usual inertial frame used is the frame of the "fixed stars". The rotating frame is often the Earth. Did you know that 747s rely on the Sagnac effect for navigation? They use laser gyroscopes, which work according to the Sagnac effect.

<i>which force makes the earth rotate on its axis ???? and if there's no force doing that, what is the cause ...</i>

The Earth was spinning when it formed out of the dust cloud which formed the solar system. Since there are very few friction effects in space, it just hasn't slowed down very much yet. There is no force needed to keep it spinning.

... it is the philosophers who understand the matter better...

Which is precisely why philosophers still are inconclusively opining wholesale on the very same indefinite indeterminates with which they long ago started their process. ;)

:D

"Science is more concerned with describing how things work than explaining the true underlying nature of things; that is a job for metaphysics."

you are partially wrong, and your own answer later on clarifies this:

you said: "They don't. When relativists say "clock" they mean "any device which can measure time". That includes you pulse, your digital watch, a swinging pendulum, the rate at which you age, your heart rate, and so on."

again, the fundamental question is: WHY does ANY of the things you name (they simply show uniform motion) MEASURE time?
where is the argument, where is the proof? You can say this is business for metaphysics but look how important this is for science. One of those last debates between philosophers and physicians I read about was about this: Does time really exist or not (and all other things related to time issues.) Of course, it ended with a huge disagreement between each other, also between the physicians!!

So, when I read that time slows down then my little alarm bell ringes also. IT is an empty claim.

Let me go into this deeper: Let us say that with a device which performs an uniform motion we can really measure time. What does this IMPLY: it implies that Time is Something that FLOWS. Whether it is a continuous flow or in pieces, it doesn't matter. Time must be something that is "flowing" by, otherwise this device cannot measure this "amount" of time. But is there anything, apart from your feelings maybe, that tells us that time "flows"? Nope.

and that is for me a very big objection against the interpretation of relativity concerning "time dilation". You name the aging of my body as a "clock". This is entirely an assumption: the "aging" can simply be explained with motion alone. Time is used as a parameter or as an "excuse" for the motion, but motion is primary. If we say something is old, like an old building: is it time that caused this? why would it be time --> the building has basically been damaged by motions, not by time
Is time needed for motion to occurre? I don't know but i wouldn't be to sure of the big YES. Time might very well be a man-made concept, which appears to be usefull in mathematics.

"Thus, science has a good description of time, but cannot explain things like why time exists in the first place."

thus science has basically no description of time, it can't say what it is, what it does and why it would change of rate at great speed
it tells us almost nothing

"The existence of the neutrino was postulated on the grounds of energy and momentum conservation issues in various nuclear processes. Energy and momentum conservation are fundamental concepts of physics."

and yet not compatible with relativity, and this is very true, conventional scientist have said this
equivalence pr. is not compatible with mass-energy conservation

"The problems raised could be fixed in two ways - throw away energy and momentum conservation OR postulate a new particle. Much less "damage" came from postulating a new particle."

no: trow away relativity or introduce a particle
it was the predition of relativity that appeared wrong
autodynamics claims to be in perfect agreement without any neutrino, you might want to verify that

"Countless subsequent experiments have tended to confirm the existence of the neutrino."

I've read about the experiments and why they don't provide the proof, but can't remember where
if i'm correct, autodynamics website has a small section on that
basically there a other things that are also neutral (like gamma rays) and which will penetrate and confuse the experiment
the claim that this is 100% prevented is not true

"Yet no experiment has contradicted it (despite certain claims you may see strewn around the internet)."

not compatible with mass-energy conservation
i gave an example from marmet earlier: inertial acceleration the mass aquirers energy, i can stand here submitted to earth's gravity all day and i don't increase my energy

"Autodynamics has been refuted by others, so I won't get into that here."

marmet says lorentz equation are correct but interpreted wrongly, i.e. the lenght of an object really physically changes (due to kinetic or gravitational energy) and not space(time)

"Much of physics is counter-intuitive. I personally find quantum mechanics much more bizarre than relativity."

It is not "bizarre" that holds me: it is the feeling that there's an easier way to explain it (and my thoughts on time I gave earlier in this post)
the world, the universe, i find everything bizarre when i think about it
life is strange

"At some stage, I will probably have to critique Marmet in detail."

probably yes

"Unfortunately, there is a lot of information there and I have limited time."

idem ditto

"If they were sound, why have they not been published in peer-reviewed journals?"

i think that question answers itself!
we all know how research in science should be and how it IS
look back in history and see: nothing has changed though many (honestly) think it has

"Regarding the Sagnac effect: the usual inertial frame used is the frame of the "fixed stars". The rotating frame is often the Earth. Did you know that 747s rely on the Sagnac effect for navigation? They use laser gyroscopes, which work according to the Sagnac effect."

the stars are not fixed, we know that
this is the objection that autodynamics puts forward: you don't need a third observer (frame whatever), it's not usefull
imagine the earth alone in space, nothing else: just you with your Sagnac experiment equipment and the earth: you do your thing, and are able to calculate the velocity of the earth's rotation
why would i need something else, why calling in "fixed" stars?

i think this issue has also a great deal to do also with Mach's principle

fort the record: i would like to find myself a descent book on relativity which must:

- explain all the principles of general and special relativity with great clarity
- for each principle an experiment is provided which shows why they are correct: no gedanken experiment --> real ones who have been done
- maths are welcome: but not too much and clear enough
- the history must also be explained: why came relativity, what was it with Lorentz, Maxwell, etc. in not in three sentences!

IS THERE SUCH A BOOK OUT THERE??? (hope so)

I've seen the term "counter-intuitive" all over the place. It's ridiculous. Through billions of years of evolution, we have existed according to physical laws of our universe. Our intuition is absolutely and irrefutably entwined with physics, in one way or another. I think the term "counter-intuitive" is used as a pseudo-philosophical back-up to support equations which seem to fit what is known yet are not actually absolute proofs. I suspect every true law of physics will turn out to be 100% in accord with our intuition. We have billions of years of life to back that up.

Years ago this hamster and a physicist built an Orbital Maneuvering Vehicle simulator. One exercise was to dock with the Hubble Space Telescope. Paradoxically, to overtake the telescope from some orbits one had to slow down. This dropped the OMV into a lower orbit allowing the OMV to rotate around the earth faster than the telescope. Then the OMV could accelerate and dock with the telescope at the higher orbit.

Intellectually this was not hard to understand. However, looking through a camera and just knowing what to do was not so easy. As the physicist described it, “It’d be easy if one had grown up as a fly on the whirling blades of a fan.”

It takes an astronaut about a day to adjust to the changed dynamics of the shuttle. At first their actions and movements are slow and stumbling. By the second day they are jumping around, grabbing things, and working at almost normal speed.

This hamster feels many aspects of General Relativity and Quantum Mechanics are counterintuitive. Quantum entanglement and ambiguities in “cause and effect” are two examples. The behavior of super cooled helium also seems bizarre to most people.

Intuition is formed from experience with normal events. Abnormal events seem counterintuitive. Part of becoming expert in a field is developing intuition for the special weirdness in that field. With extensive experience an expert just feels that a certain concept is right. Then a new phenomenon comes along and the expert’s intuition isn’t any better than a child’s.

In NASA shuttle experiments involving astronauts playing with tennis balls and such, the astronuats demonstrate an almost inborn ability to judge how the ball will move in the microgravity of orbit. (Was all in New Scientist a few months back.) The people studying humans in space were starting to get the idea that we have a natural understanding of physocal laws even if only subconsciously.

I have piloted a 2,500-odd ton frigate. It can be surfed along a big enough wave just like a surfboard on smaller waves near the beach. I could do this almost as soon as I began piloting the vessel; it only took enough time for me to learn the motions of the vessel itself.

If something appears counter-intuitive, it is in my opinion because the idea is not properly understood. We are working with incorrect ideas which seem to fit but may not be the best solution. And when a moresuitable explanation is thought up, I suspect it will be perfectly intuitive.

Only a day to adjust to moving in space? After decades on the ground? Seems rather intuitive to me.

Intuition is more than learning by experience. In psychology, one of the rather famous experiments you might study involves having babies crawl along ashort corridor which has two different sides; on one side the floor is solid, while on the other the floor is a thin cover over a hollow area (the thin floor is stong enough to support the weight). The babies almost without exception crawl along the solid side, skirting around the hollow area. Other animals in the same experiment do the same. Pick a forest animal, and wonder why it will run from a forest fire. It has not been burnt alive before. Why does a young gazelle run from predators? Intuition. Not learning from experience.

This hamster applauds anyone wishing to develop more understandable theories.

Evolution operated in the macroscopic earth environment. Would that evolutionary “learning” help an animal or a human understand Relativity or Quantum Mechanics? To the degree those theories describe everyday physics it might. But near the speed of light or at nanometer scale? Or exotic substances near absolute zero? Perhaps.

Animal evolution has embedded innate survival information that in humans may form a component of intuition. However humans are far more guided by learning than by instinct. Instinct and early cultural training might have to be un-learned before new intuition could develop for an unusual subject. (A human might have to learn that it is safe to walk across a narrow bridge over a chasm. Some humans may never overcome that instinctive fear.)

(This hamster may have a differing meaning for “intuition”. This hamster includes the insight that develops in chemistry, biology, mathematics, engineering, etc. that is acquired through the experience of working and thinking with concepts for years.)

c'est moi:

<i>WHY does ANY of the things you name (they simply show uniform motion) MEASURE time?</i>

Can't we avoid this whole problem by defining time as "what clocks measure"? If clocks don't measure time, what are they for?

Interestingly, relativity doesn't describe time as "flowing". Time is just a co-ordinate, similar to a spatial co-ordinate. Why humans perceive time as flowing is an interesting philosophical question.

<i>thus science has basically no description of time, it can't say what it is, what it does and why it would change of rate at great speed it tells us almost nothing</i>

The scientific definition of time is linked into all areas of physics. Physics wouldn't exist without the concept of time. I'd say science says a lot about time. It doesn't answer the big question of "why time?", but then, it doesn't answer those sorts of questions at all.

<i>Energy and momentum conservation are fundamental concepts of physics. ...

and yet not compatible with relativity, and this is very true, conventional scientist have said this equivalence pr. is not compatible with mass-energy conservation</i>

Which scientists said that? They are wrong.

<i>i gave an example from marmet earlier: inertial acceleration the mass aquirers energy, i can stand here submitted to earth's gravity all day and i don't increase my energy</i>

You are in the same non-inertial frame as the Earth whilst you stand on its surface.

<i>the stars are not fixed, we know that</i>

The term "fixed stars" really means "distant stars and galaxies" - all the other "stuff" in the universe. Mach's principle is very relevant here, as you say.

<i>just you with your Sagnac experiment equipment and the earth: you do your thing, and are able to calculate the velocity of the earth's rotation</i>

No. If there was nothing but the Earth in the universe, how would you know it was rotating? All rotation is with respect to something (i.e. relative).

<i>i would like to find myself a descent book on relativity which must</i>

The general relativity bible is probably Wheeler's <i>Gravitation</i>, though it is pitched at a reasonably high level. It has everything you've asked for. Maths and relativity are closely linked, so if you want the details it's hard to avoid the maths.

This hamster intends studying gravitation when the comic book version is released. John Wheeler’s book is way too thick, not light reading for an evening. It’s also thirty years old. Is it still relatively up to date? Know any good online tutorials?

"No. If there was nothing but the Earth in the universe, how would you know it was rotating? All rotation is with respect to something (i.e. relative). "

I know this because of the difference in time I measured
it's that easy

you still haven't dealt with Marmet .............. ;)

bump

c'est moi:

I just had a look at Marmet's book (on the web) about Classical mechanics vs. Einstein's relativity.

He goes to a lot of trouble to establish the Lorentz transformations and so on, which are exactly the same as Einstein's equations. However, in the process, Marmet builds into his theory an idea of an absolute rest frame.

I went looking for a point of conflict between Marmet's theory and relativity. Sure enough, in section 3.9 he writes:

<i>Contrary to Einstein's claim, the energy given to a mass accelerated with respect to [a] train must depend on the direction of its velocity with respect to the direction of the velocity of the train. When the directions are opposite, the two velocities (whose magnitudes are equal) cancel out and the mass of the body must come back to its original value in the [absolute] rest frame. Otherwise we would discover that atoms of matter having traveled to another frame would have a different mass after their return to the initial frame. We must conclude that two frames cannot be equivalent when there exists a relative motion between them.</i>

This conclusion is experimentally testable. In essence, Marmet is saying that the length contraction and time dilation effects are not seen equally in two reference frames moving at a constant relative speed to each other. He says that observers in both frames would see one of the frames' clocks slowed down with respect to the other frame. Einstein, on the other hand, says that <i>both</i> observers will see the other's clock slowed down. Experiment supports Einstein, not Marmet.

No more reading is necessary.

A photon does indeed have a mass. Light is made of Photons and if one were to pass light by a black hole the light would refract (bend)into the black hole, this is due to the "mass" of the light or the Photon, Black Holes only attract things that do indeed have a mass. A Photomic mass is quite small but that is because it is a sub atomic particle, meaning "Being able to *live* or stay inside an atom" or "smaller than an Atom"

S Dalal

A photon does indeed have a mass.

That is quite an interesting claim. Can you provide any evidence?

Light is made of Photons and if one were to pass light by a black hole the light would refract (bend)into the black hole, this is due to the "mass" of the light or the Photon, Black Holes only attract things that do indeed have a mass.

Another outrageous claim. I'm beginning to get the feeling you don't know what you're talking about. Can you produce evidence?

A Photomic mass is quite small but that is because it is a sub atomic particle, meaning "Being able to *live* or stay inside an atom" or "smaller than an Atom"

Now I'm convinced you have no idea what you're talking about. What is a "photonic mass?" How does it *live* inside of an atom?

Hi,

I was wondering...is earth an inertial frame of reference?if so why?(it should not be,i think)because of revolutions that change velocity(in terma of directions i mean)...:confused:


bye!

Earth is non-inertial, but is approximately inertial in a small enough region (e.g. your living room, for many purposes, can be considered to be a good approximation to an inertial frame).

Okay,so what you mean is that during our regular lab experiments,eg with bob of pendulams etc,we can approximate earth to be an inertial frame of reference.cool.
:cool:

Thanks.
bye!

Hey, (Q), please dont bacsh my head in if i'm wrong, but i think it was einstein who took a pic of the night sky and one again during an eclipse, and, by comparing the two, showed that the sun's gravity bent the light from the stars...

also, i have this cool glass thingy that has a lil cross that spins when you put it in the sun... now, i know very little about physics and atomic physics and astro physics compared to what there is to know, so dont kill me if im wrong...

peace out, luv u all ;)

Gross

I know that in 1911 he made preliminary predictions about how a ray of light from a distant star, passing near the Sun, would appear to be bent slightly, in the direction of the Sun. However, I had not heard about his pictures. Have you got a link?

http://www.astr.ua.edu/keel/agn/qso2237.html

http://antwrp.gsfc.nasa.gov/apod/ap001010.html

http://www.aip.org/history/einstein/

No, i heard it from a friend.

PS. Also, black hole theory is also greatly based on bending of light due to gravity, no?

Oops! Sorry James, I didn't immediately understood what you were saying and then I forgot about it. appreciate you took the time!


He goes to a lot of trouble to establish the Lorentz transformations and so on, which are exactly the same as Einstein's equations. However, in the process, Marmet builds into his theory an idea of an absolute rest frame.

-> without using any relativity principles


I went looking for a point of conflict between Marmet's theory and relativity. Sure enough, in section 3.9 he writes:

there must be loads of them


This conclusion is experimentally testable. In essence, Marmet is saying that the length contraction and time dilation effects are not seen equally in two reference frames moving at a constant relative speed to each other. He says that observers in both frames would see one of the frames' clocks slowed down with respect to the other frame. Einstein, on the other hand, says that <i>both</i> observers will see the other's clock slowed down. Experiment supports Einstein, not Marmet.

this is what I don't get

"He says that observers in both frames would see one of the frames' clocks slowed down with respect to the other frame."

"Einstein, on the other hand, says that <i>both</i> observers will see the other's clock slowed down."

i don't see the difference between these two??
in the first one you do say that BOTH will see the other one's clock slow down
--> the difference is I believe that Marmet wants a universal time used as an absolute reference

I think this part is not interesting at all
what was so crucial in our discussion was the number 1 here:
1. Marmet explained length contraction and timedilation mechanically (see two different papers on that)
--> if this doesn't make sense, then you've got a big devastating objection against him
2. Marmet explains and calculates the orbit of Mercurius without any notion of relativity
--> and this was at the time seen as a major blow against Netwon physics and a great victory for relativity

it easier of these two things to see if they make sense or not, easier than discussing frames of reference and switching between these frames and stuff like that
i don't even agree with marmet on these reference things

PS. Also, black hole theory is also greatly based on bending of light due to gravity, no?

Black hole theory is postulated by General Relativity. Matter causes spacetime to curve. The curvature of spacetime IS gravity.

good point (Q)

c'est moi:

Marmet may be able to derive certain results of relativity using different assumptions. However, his theory must match experimental results <i>in full</i>. It is not enough that it predicts <i>some</i> experimental results and not others. Relativity is compatible with <i>all</i> the observations (at least, so far).

I pointed out one example where Marmet is in conflict with observation. That is enough to sink his theory, just as Einstein's theory would have to be thrown out if it disagreed with an observation.

To clarify my previous point: Take two observers A and B. A is at rest, B is moving with constant speed.

According to Einstein, A would see B's clocks as running slower than his. and B would see A's clocks running slower that his.
According to Marmet, both A and B would see B's clock running slower than A's. Experiments support Einstein.

Seems to me they would only see each other's clocks slower because of the decreasing frequency of light between them due to moving away. The clocks are still running the same speed for both of them, they are still sharing the same time, there is no "time travelling". Same as sound waves if two are moving apart, you get decreasing frequency. The frequency is the same as always of course, but the point where we interact with it decreases in frequency.

Adam,

The Newtonian and relativistic Doppler shift formulae are different. Experiment supports the relativistic formula. The apparent frequency change cannot be explained solely by the relative motion (i.e. the "normal" Doppler effect), but needs relativity.

Oh well, this is just mroe stuff I have to study. I'm not sure if my current degree will cover these things.

According to Einstein, A would see B's clocks as running slower than his. and B would see A's clocks running slower that his.

okay, now you're being more clear

Question: you talk about experiment, but I have no idea about which experiment you are talking here :confused:

All of our experiments on Earth are done in a reference frame moving with respect to the sun, the centre of the galaxy and so on. Yet the Lorentz transformations make the correct predictions for time dilation as observed on Earth, <i>without taking into account the Earth's motion with respect to the sun</i>. Thus, for example, we see the lifetimes of muons hitting the upper atmosphere as being longer than when the muons are at rest, but precisely the amount that they would be longer if we did the experiment in a reference frame at rest with respect to the sun.

This means that Einstein was correct when he postulated that there is no absolute rest frame. Experiments such as the Michelson-Morley experiment confirm that, too.

Marmet is going back to the days when we had an "ether", which was supposed to provide an absolute rest frame. Unfortunately (for Marmet), the ether doesn't exist.

"All of our experiments on Earth are done in a reference frame moving with respect to the sun, the centre of the galaxy and so on. Yet the Lorentz transformations make the correct predictions for time dilation as observed on Earth, without taking into account the Earth's motion with respect to the sun."

hum, I see no reason why they should?
but again, what experiment does exactly give the results that you talk about with A at rest and B moving
as far as I get it, when A is at rest and B is moving near speed of light and both have clocks they both will see each other's clock run slower, because of the relativity principle you can ask "who's really moving? Both can say that they are moving near the speed of light in respect to each other", hence for relativity it is vital that both see this slowing down
I don't see how those muons a little further explain this ...

"Thus, for example, we see the lifetimes of muons hitting the upper atmosphere as being longer than when the muons are at rest, but precisely the amount that they would be longer if we did the experiment in a reference frame at rest with respect to the sun."

Don't you mean mesons here? (sorry, I'm not into physics like you!)

"This means that Einstein was correct when he postulated that there is no absolute rest frame. Experiments such as the Michelson-Morley experiment confirm that, too."

I find myself not in the position to talk about whether I find an absolute frame of reference possible or not, want to read more about that first in order to understand this issue better.

Marmet and Haspden and others, on the other hand seem not to agree on the interpretation of the results:

http://www.energyscience.co.uk/tu/tu18.htm
http://www.newtonphysics.on.ca/faq/Michelson-Morley.html

"Marmet is going back to the days when we had an "ether", which was supposed to provide an absolute rest frame."

Fact is that vacuum is not empty and is filled with activity of virtual particles. Whether it has those properties that Harold claims it has or not, I don't know.

what experiment does exactly give the results that you talk about

"During October, 1971, four cesium atomic beam clocks were flown on regularly scheduled commercial jet flights around the world twice, once eastward and once westward, to test Einstein's theory of relativity with macroscopic clocks. From the actual flight paths of each trip, the theory predicted that the flyng clocks, compared with reference clocks at the U.S. Naval Observatory, should have lost 40+/-23 nanoseconds during the eastward trip and should have gained 275+/-21 nanoseconds during the westward trip ... Relative to the atomic time scale of the U.S. Naval Observatory, the flying clocks lost 59+/-10 nanoseconds during the eastward trip and gained 273+/-7 nanosecond during the westward trip, where the errors are the corresponding standard deviations. These results provide an unambiguous empirical resolution of the famous clock "paradox" with macroscopic clocks."J.C. Hafele and R. E. Keating, Science 177, 166 (1972)

I don't see how those muons a little further explain this ...

In the muons frame of reference, it's *rest* lifetime on its clock is 2 nanoseconds (2x10^-6 seconds). Light travels about 600 meters in this timeframe. An observer in this frame views the muons clock as running slow. An Earth observer views muons traveling a shorter distance in a laboratory than light could travel in the muons rest lifetime and reckons the muons clock is running fast compared to the Earth observers clock. The traveling muons lifetime as measured by the Earth observer is longer than when the muon is at rest and as we all know, moving clocks run slower compared to stationary clocks. In the muons frame, the distance traveled through the atmosphere is less than the Earth observer measures it to be in their own frame.

Therefore, the muon travels farther than 600 meters in the Earth observers laboratory because the muons lifetime is dilated.

"During October, 1971, four cesium atomic beam clocks were flown on regularly scheduled commercial jet flights around the world twice, once eastward and once westward, to test Einstein's theory of relativity with macroscopic clocks. From the actual flight paths of each trip, the theory predicted that the flyng clocks, compared with reference clocks at the U.S. Naval Observatory, should have lost 40+/-23 nanoseconds during the eastward trip and should have gained 275+/-21 nanoseconds during the westward trip ... Relative to the atomic time scale of the U.S. Naval Observatory, the flying clocks lost 59+/-10 nanoseconds during the eastward trip and gained 273+/-7 nanosecond during the westward trip, where the errors are the corresponding standard deviations. These results provide an unambiguous empirical resolution of the famous clock "paradox" with macroscopic clocks."J.C. Hafele and R. E. Keating, Science 177, 166 (1972)

I don't get it Q, this is not we need here
we need something where one clocks passes by another one near the speed of light
both oberver will have to see each other's clock slow down
i don't think the pilots saw the clock of the US Naval O. slowing down

But that is what the Muon experiment shows.

A muon exists for such a short time that those created in the upper atmosphere should not reach the Earth. Yet we do. This is explained by the fact that to a muon travelling at near light speed only a fraction of a second occurs, short enough it does not decay. To us, at rest a much longre time period elapses and it does not decay.

Hang on a second. The clocks int that experiment were off around ther world. There was a difference in them when compared later. Yet this difference is not being attributed to simlpe motion one way and the other. Whereas in a similar experiment (that big loop on the group, or square, with a light beam sent both ways around it), it is attributed to the simple fact of Earth's spin, or so it seems to me. It looks like they are the same effect but explained two different ways.

But that is what the Muon experiment shows.

okay thed, let me think about this BUT they shouldn't have given the plane experiment, cause I know it and we don't need it here ... :cool:

But that is what the Muon experiment shows. A muon exists for such a short time that those created in the upper atmosphere should not reach the Earth. Yet we do. This is explained by the fact that to a muon travelling at near light speed only a fraction of a second occurs, short enough it does not decay. To us, at rest a much longre time period elapses and it does not decay.

hum, I don't think it proves it

-----> it proves it for you cause you *assume* a few things

.........*....muon travelling at high speed







....¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨...earth surface + observer with clock

- observer measures let us say a few seconds, that's what it takes for the muon the reach us
- but muons normally decay already in this timespan
- conclusion, time went slower for the muon, it went faster for us

But what was of importance for us in THIS discussion? James R rightly said that, in this case, IF such a muon would see time slowing down there where the observer is with his clock, then marmet cannot be correct and relativity is.

I don't see, again, how the muons bring any clarity in this. James R told me experiment contradiced Marmet. I don't see this.

follwing seems to be the key in this discussion:


In the muons frame, the distance traveled through the atmosphere is less than the Earth observer measures it to be in their own frame.

--> aren't we talking about time dilation? it seems that here Q is talking about the distance ... I thought the point was that muons' time went slower so, logically, they would decay longer and thus travel a greater distance ...


Therefore, the muon travels farther than 600 meters in the Earth observers laboratory because the muons lifetime is dilated.

great. but it stil doesn't explain what James R said was prooved experimental
OUR clock has to be seen slowing down as well
this has not been seen as far as I know NOW

up

cest moi

Simple apply James R explanation on SR from the other light/mass thread tho the muon experiment and you should be able to put it all together.

I tried Q, I think James R explained it very well but that's not the prob I think.

He said:


"To clarify my previous point: Take two observers A and B. A is at rest, B is moving with constant speed.

According to Einstein, A would see B's clocks as running slower than his. and B would see A's clocks running slower that his.
According to Marmet, both A and B would see B's clock running slower than A's. Experiments support Einstein."

I am still waiting 4 such an experiment. the muons do not show this

..both A and B would see B's clock running slower than A's. I am still waiting 4 such an experiment. the muons do not show this

Yes they do. Quite well in fact. But what you're inferring is that if A is the muon and B is the Earth observer in the lab, then the Earth observer views his own clock as running slow. He doesn't, he views his own clock as running normal relative to his lab.

Maybe you should Marmet first cause that's what it is about.

james r says that:

"According to Marmet, both A and B would see B's clock running slower than A's"

I haven't read where Marmet says so in fact ... (sometimes I just get confused with all those FOR etc. that at the end I don't know anymore what they are trying to say)

Let me say my position (which I think is also Marmet's position):

the muon can't see his own clock slowing down
you don't know good if there's no evil ... you see what I mean

A slows down
B sees A slow down
A does not see B slow down

Einstein says A sees B slow down as well
where is the experiment ...

A slows down
B sees A slow down
A does not see B slow down

Einstein says A sees B slow down as well
where is the experiment ...

A will view B clock as going slower. B will view A clock as going slower. Why? Simple. Because there is no absolute frame of reference. Neither A nor B can tell which one is in motion. Is the muon traveling near light speed compared with the Earth observer or is the Earth observer traveling near light speed compared with the muon? Neither can say, absolutely.

That is the "crux of the apostrophe.' Zappa

I was promessed that experiment proved this. I am still waiting for it.

I was promessed that experiment proved this. I am still waiting for it.

You can prove it yourself. Get in your car, drive somewhere so that a large truck blocks out the view completely outside the drivers window. Now wait till the truck begins to move. If your view was that of the truck ONLY, how is it that you are able to tell, absolutely, that it is the truck moving and not you. Without the reference of the ground or other surroundings within your view, you can't. In fact, if your on a hill and you release the brake, you can't tell if you're rolling or whether the truck is moving. It's really that simple.

I thought there would have been a nice experiment which ultimetly proves that both clocks slow down. Since there is only the principle itself left, I can think and read some more about the very principle itself without worrying about such an experiment.

(just a thought: When I lift you up and I throw you away in the sky at a considerable speed (i'm superman) would you say that you don't feel any different and that it could be me + the earth who's moving away from you?)

(just a thought: When I lift you up and I throw you away in the sky at a considerable speed (i'm superman) would you say that you don't feel any different and that it could be me + the earth who's moving away from you?)

YES !!! You got it.

exactly, it's absurd

c'est moi,

Now you know why we can't win any arguments on these boards.

It's hard to prove something using logic to illogical people.

Tom

c'est moi:

I tried to explain experimental evidence to you before, but it seems I need to try to find a simpler, more transparent explanation. I will think about that and get back to you.

In the meantime, consider this:

Imagine you are the only thing in the universe. You look around you and all you see is empty space. There's no gravity, nothing to pull you in any direction. Just you and space. Ask yourself: is there anything you can do to tell if you are moving or not? I don't think there is.

Now, imagine there are two things in the universe, say you and a soccer ball, separated by some distance. You see the ball coming towards you. Again, ask yourself: is there any experiment you can perform to tell if it is really you or the soccer ball moving? I don't think there is.

Now, consider you and the Earth. You are out in space and you see the Earth coming towards you. Is there any way you can tell that you are moving towards the Earth and that the Earth is not moving towards you? Well, you might answer that you can look at the sun, or the moon or satellites orbiting the Earth. They all seem to stay in the same place relative to each other, and they all seem to move in the same way relative to you, so perhaps that tells you that you are moving? But consider what it really tells you. It tells you NOTHING about you "absolute" movement. All you know is your motion relative to the Earth and the satellites and the sun and so on. You can NEVER know whether it is you or the rest of the stuff in the universe which is moving. Wrap a box around yourself and as you fall towards the Earth there is NO experiment you can perform in the box which will tell you that the box is falling towards the Earth rather than floating freely in deep space.

That is the essence of relativity. There are no preferred reference frames.

What about tidal forces inside that box?

Originally posted by Joeblow93132
Lua,

As you can tell from the reactions to my comments, most people on this board, and probably most scientists, believe that photons have no rest mass.

Not a belief, it's based on fact. How can a EM wave have rest mass? Maxwell's equations (50 yrs before Einstein) explained this.
Why are having problems understanding physics nearly 150 yrs old.


When they are faced with the question of why the paths of photons curve when passing by massive objects, the say "Well, Einstein says that space is curved around large objects, so the path of photons will curve even though the don't have mass".

Non sequitur


I, on the other hand, don't believe that space gets curved because atractive forces also exist in magnetic and electric fields, and these fields can't be explained by the "curved space" theory.

You obviously don't understand that they are different. Apples and oranges. Maxwell explained electromagnetism, learn that first.


Therefore, if you assume that space is not curved, then photons have to have mass or they would always travel in straight lines.

You can assume electrons don't have charge so electricity is the flow of tapioca. It has as much validity.


Neutrino's, if I am correct, are thought to be expelled at high speeds, and since they don't react with regular matter, they continue to move at these speeds.

They do, your ignorance of fact is outstanding.


(The neutrino was never really proven to exist, it is probably just a theoretical particle that a scientist made up so that his equations would balance out)

So what do they detect in neutrino detectors? More ignorance from you.


Q,

"Could you please explain to Lua how a photon *with* mass can be 'at rest?' How does a photon *with* mass experience acceleration? "


Easy. A photon has mass and a gravitational field. But unlike normal matter, the gravitational field of a photon is BIPOLAR. This would explain why photons accelerate to light speed, and travel at lightspeed. This would also explain why their paths bend when they pass massive objects.

WTF is a bipolar gravitational field vs a monopolar field.


The gravitational field of an object is space with higher or lower amounts of energy(quants)

Inventing new terms for the sake of it?

The only Quant I know of is Mary.


The space closest to a large object has the most energy(gravity), and the energy becomes less as you move away from the object. When two fragment of space(with certain energies) meet, they're energies merge and the become one fragment of space. Since where there were two fragments of space, there is now only one, the objects move closer since the space between them is actually dissapearing. I would like to give an even more detailed explanation, but I have to get back to work.
[/QUOTE]

Total and complete baloney. My bogosity meter just pegged.

Hamster,

I'm talking about a small enough box here. The equivalence principle is a local theory, as I suspect you are aware.

James R., this hamster’s physics is rusty and limited. Have read about equivalence of inertial mass and gravitational mass. However this pedantic hamster believes that any box sufficiently large as to contain a hamster is also large enough that the difference in the inverse square gravity field of the Earth along the length of the box should allow detection of the gravity field. Observation of a ball placed slightly off the box center should suffice as it moves to an end of the box. Each point in the hamster sized box follows a distinct space-time curve that should indicate the presence of Earth’s gravity.

In the experiment presented it should be possible to determine whether the box is accelerating toward Earth rather than floating freely in deep space.

(Didn’t mean to detract from your explanations. This hamster learns from reading these threads.)

double post :D

Wrap a box around yourself and as you fall towards the Earth there is NO experiment you can perform in the box which will tell you that the box is falling towards the Earth rather than floating freely in deep space.

Imahamster made an interesting comment on that ... let us see

James, let me reply with some of the thoughts that occure to me when I read your explanation of FOR's. When a photon travels from the sun the to earth, would you say that the earth is moving towards the photon (and the sun)? Or the opposite? It's simple, it's the photon which travels to the earth from the sun. When you imagine this and imagine that (only me in space), you take away information for the observer. Because we lack information a new priniciple is suddenly a law of nature? It only means that we as observer are limited in doing science.

Let us see, I see the earth coming towards me. What could be the reason? I am still in the solar system, right? We know our solar system does have a velocity. But, I am IN the solar system. I have the momentum of the solar system. I travel along with the solar system. Earth is coming closer you said? There can be only one reason and that is because I have accelerated. I don't need other reference frames. What the observer needs is information of both entities (put a light source on of the two and you can calculate the only variable you need which is Time). What relativity does in the equations is drag in a third observer. This is why you get time dilation and the rest. If you have logic and the necesairry information, you will be able to know who's moving. You will be able to show with quantum mechanics why the clock of the moving observer will slow down.

And let us not forget in this discussion the question "Did the Michelson-Morley experiments prove there was no "aether wind"?

They have been accepted by almost everyone as giving a "null" result, but in point of fact they showed a very interesting periodic variation indicating the presence of an aether wind, though not the one they'd been looking for! Dayton Miller devoted a great deal of time and effort to doing more experiments to investigate the variations, which proved to be reproducible but to show systematic changes with time of year and some other factors. He also showed, incidentally, that the effect disappeared if you put the apparatus in a thick-walled enclosure!!! (he summarised his work in great detail in a review paper in 1933: Miller, Dayton C, “The Ether-Drift Experiments and the Determination of the Absolute Motion of the Earth”, Reviews of Modern Physics 5, 203-242 (1933)

The most reasonable interpretation of his results was that either the earth was moving pretty fast (about 200 km/sec, faster than it moves around the sun) in a direction roughly perpendicular to the plane of the solar system, or the aether was moving in the opposite direction at that speed. The aether seems to be moving like a fluid (in fact, it is like a crystal fluid), going with much slower relative velocity near solid bodies, thus accounting for the apparently modest speed (about 10 km/sec) indicated by Miller's experiments.

It appears that there was a major difference of opinion between Miller and Einstein. Einstein's Special Relativity theory demanded that the Michelson-Morley experiments must have been null. The aether was not acceptable.

By 1955 the aether had become a dirty word. Even in 1940 or so, you can find no reference to Miller's existence in Herbert Ives' papers (I'm still seeking more info of the latter, cause as some here will know this famous scientist performed some experiments which he said contradicted relativity). The 1979 Brillet and Hall experiment*, currently accepted as an accurate confirmation of Michelson and Morley's "null" result, appears to have been conducted in ignorance of Miller's work. They seem to have been unaware of Miller's conclusion that the aether wind can only be detected in the open!!! Their temperature-controlled Fabry-Perot interferometer would have had little chance!

c'est moi:

The Michelson-Morley experimental result has been confirmed many many times. There is no detectable aether. Perhaps there is an aether which contrives to be undetectable, but in that case it is ruled out by Occam's razor.

Regarding reference frames, here's what Galileo had to say:

"Shut yourself up with some friend in the main cabin below decks on some large ship, and have with you there some flies, butterflies, and other small flying animals. Have a large bowl of water with some fish in it; hang up a bottle that empties drop by drop into a wide vessel beneath it.

With the ship standing still, observe carefully how the little animals fly with equal speed to all sides of the cabin.

The fish swim indifferently in all directions; the drops fall into the vessel beneath; and, in throwing something to your friend, you need to throw it no more strongly in one direction than another, the distances being equal; jumping with your feet together, you pass equal spaces in every direction.

When you have observed all of these things carefully (though there is no doubt that when the ship is standing still eveything must happen this way), have the ship proceed with any speed you like, so long as the motion is uniform and not fluctuating this way and that.

You will discover not the least change in all the effects named, nor could you tell from any of them whether the ship was moving or standing still.

In jumping, you will pass on the floor the same spaces as before, nor will you make larger jumps toward the stern than towards the prow even though the ship is moving quite rapidly, despite the fact that during the time that you are in the air the floor under you will be going in a direction opposite to your jump.

In throwing something to your companion, you will need no more force to get it to him whether he is in the direction of the bow or the stern, with yourself situated opposite.

The droplets will fall as before into the vessel beneath without dropping towards the stern, although while the drops are in the air the ship runs many spans.

The fish in the water will swim towards the front of their bowl with no more effort than toward the back, and will go with equal ease to bait placed anywhere around the edges of the bowl.

Finally the butterflies and flies will continue their flights indifferently toward every side, nor will it ever happen that they are concentrated toward the stern, as if tired out from keeping up with the course of the ship, from which they will have been separated during long intervals by keeping themselves in the air....

Galileo Galilei, Dialogues Concerning the Two Chief World Systems (February 1632)
-----------------

In fact, there is <i>no</i> experiment you can do inside the ship which will distinguish the ship moving at a constant velocity from when it is at rest. That's the basis of relativity. There simply is no universal standard of rest.

Presumably an astronaut in orbit can compare his orbiting clock to signals coming from a clock on earth and detect that the clock on earth is ticking faster. This doesn’t contradict Special Relativity as the astronaut is experiencing continual acceleration.

If the astronaut wasn’t orbiting the earth but was moving with constant velocity, then Special Relativity says the astronaut would see the earth clock as ticking slower while C’est moi seems to believe the astronaut would still see the earth clock as ticking faster.

What experiment could be performed to resolve this question?

What about communication between earth and Voyager? Voyager is traveling fast and shouldn’t be very affected by the sun’s gravity field. After correcting for Newtonian Doppler affects what frequency adjustment is needed for communications frequency synchronization with the Earth station? Presumably the Voyager instrument frequency setting should suffice as an observation from a moving frame of a “stationary” Earth clock? Just have Voyager telemetry report the instrument frequency setting and one should know whether Voyager sees the Earth clock moving slower (lower frequency) or faster (higher frequency).

(Don’t expect the Voyager instruments to be sufficiently accurate for this measurement but future missions might do this.)

Hamster,

I suspect that there would be a frequency shift in two-way communication with Voyager, which would be small but detectable. This could well confirm the relativistic time dilation. However, I'm not sure if this has been published. I am reasonably certain that it would need to be taken into account by the guys at NASA, but I'm equally sure they take relativity so much for granted that they would not make a big deal out of this.

"The Michelson-Morley experimental result has been confirmed many many times."

you are wrong and it seems you didn't even read what I said

see 'Fresnel drag' now

--> do we have to assume that the aether had to be something at absolute rest on a universal scale?? NO
the aether is 'that unseen something that can store energy and affect light propagation but yet fills any free space in and around the protons and electrons and their derivative particles that we do see as the matter form'.

the aether which was not detected is the aether that they thought to be at absolute rest

correlation with the Fresnel drag: if you measure the speed of light in a block of glass or in a tank of water the speed is reduced below that applicable in the vacuum, reduced by the refractive index IF the glass or the water is moving through space and relative to the laboratory frame, then the speed of light in passage through that medium is affected by that speed. It is a function of the speed of the test medium and the speed of that medium relative to the laboratory frame. The experiments on this provide the formula for the drag coefficient involved and is called the 'Fresnel drag coefficient'.

There need be no matter in the space between the optical components of the aether experiment, but yet the aether can be affected as if its density were changed. "How?"
19th century physicists were puzzled by the aether because it exhibits some properties telling us it is a fluid and some telling us it is a solid. That was the perception from a time when little if anything was known about 'fluid crystals'.

So if the apparatus of the Michelson-Morley experiment entrains effects akin to the action of electric fields, why should it not drag some of the structured solid-like (or crystalline) aether along with it, only to allow this to dissolve into fluid-like form which can flow backwards freely through the interstices of the solid portions of the aether to keep density constant and, indeed, avoid setting up any linear aether momentum.

Fresnel drag coefficient and its relevance to the aether and the interpretation of the null finding in the Michelson-Morley Experiment.

quote from "The Elusive Ether, A T Jackson writing about the detection of the ether (Physics Education 1974, v. 9, p. 265):

"the most important fallacy in Fresnel's drift theory would seem to be that he assumed the moving medium dragged both the light and the ether along with it, although the existence of the ether had not been established'."

Yet Fresnel's formula was verified by Fizeau and it was Michelson and Morley who assumed that the ether did not move with the earth and then were surprised to find that the earth's motion through the ether defied detection.

If the role of the ether in controlling light propagation is analogous to the role of a substance in transmitting sound, the propagation velocity c1 is proportional to (P/d)1/2, where P is a pressure modulus and d is density. Since the speed of light is fixed at c and refractive index n is c/c1, we then find that n2 is proportional to d. Now, Fresnel said that the velocity of light would be increased by u(1-1/n2) due to motion of a disturbing medium at velocity u. If then the ether has structure and its bulk has density dk that moves as a disturbance at velocity u, we may write:

n2 = 1 - k
uk + v(1 - k) = 0
because n equals 1 when k equals zero and the ether exerts no linear force on matter, meaning that its momentum is conserved as k varies.
It is then a simple matter of algebra to show that u(1-1/n2) is simply v. This means that the velocity of light relative to the earth frame is constant, as Michelson and Morley found

It defies all logic to quote the Michelson-Morley experiment as evidence disproving the existence of the aether when all it did show was that the speed of light is affected by the motion of that medium through which it is propagated.

We see no discussion in the textbooks of the fact that the light rays in the experiment were not propagating freely through empty space, as was assumed. Those rays were encountering full frontal collision with their own reflection from mirrors, meaning that the energy they conveyed had to struggle to penetrate through the energy associated with those reflected waves!! The null result of the Michelson-Morley experiment should never have been regarded as a sufficient reason to abolish belief in the existence of an aether. At best it proved that some preconceived notions about the aether were false but the aether cannot be eliminated because a few physicists had some false ideas!

"In fact, there is no experiment you can do inside the ship which will distinguish the ship moving at a constant velocity from when it is at rest. That's the basis of relativity. There simply is no universal standard of rest."

again, does it matter?? what Galileo is doing is (again) taking information from the observer
I don't say it is wrong, I simply say that because of this lack of info, we shouldn't believe SR which says more that all laws of physics are the same in ineterial frames (--> this is exactly why it is not allowed to search for mechanical effects which would cause a clock to change its rate)

(your example on earth and moving observer was equally easy to explain, it is basically always the same: lack of information + if there is an aether then we do have an absolute frame of reference)

the more I understand relativity in this very valuable discussions (at least for me :p ) the more I am convinced that I choose the right side. Luckily, science is still doesn't work like democracy. One little man can change everything. When the time will be ripe, relativity will slowly get replaced.

c'est moi:

Unfortunately, the more you write, the more I don't think you understand relativity. To me, it seems like you are cutting and pasting chunks of text from other sites (mostly nutter "alternative physics" sites). If you are doing that, you should acknowledge your sources. If not, I apologise for getting the wrong impression.

One of the things you wrote above was:

<i>IF the glass or the water is moving through space and relative to the laboratory frame, then the speed of light in passage through that medium is affected by that speed. It is a function of the speed of the test medium and the speed of that medium relative to the laboratory frame.</i>

This is incorrect.

"Unfortunately, the more you write, the more I don't think you understand relativity."

I said what I thought about the very principle of relativity
got nothing more to say
I think that you can't even think outside relativity

and indeed, the quote is taken from aspden's site cause I have no such book here
so is the piece with "n2 = 1 - k
uk + v(1 - k) = 0
because n equals 1 when ..........."
i gave the site so many times, you could have recognised it .... and i am a lazy guy

Is quoting from http://www.energyscience.co.uk/tu/tu05.htm

Dr. Aspden also believes the Sun is not powered by Fusion. I seem to recall a conversation I had with Dr. Aspden arguing about this.

"Dr. Aspden also believes the Sun is not powered by Fusion. I seem to recall a conversation I had with Dr. Aspden arguing about this."

the sun is powered by fusion (I'm sure there's a lot of stuff I don't agree with him)
but how does the fusion happen? you can overwin statistics by huge density and squeesing matter very hard or you can have it happen in a similar way that scientist do it here on earth

c'est moi,

How do scientist do fusion on Earth?? Are you referring to cold fusion??? :bugeye:

Tom

I am simply talking about 'hot' fusion --> speeding particles up and kaboum (no high density required, isn't it?)

drop the aether
I said some things which are 100% of my own concerning Galileo's principle of relativity

BUMP 4 that last thing

I guess you won't answer

Doesn't look like it. Are you talking about bombs or something, because fusion cannot be controlled as far as we know (or I know). We've only got lamo fission now.

This is my first post in these forums btw :p

Fusion can indeed be controlled. (http://www.jet.efda.org/index.html)

Well call me a monkey and spank me bitter! That certainly looks like fusion work! So fusion must be possible...although it does not say it has been harnessed...the title itself "European Fusion Development Agreement" suggests that it is not presently possible, "development" being the key word.

But they're working on it. And good too, 'cos there's a lot of useful power in that little reaction (if 'reaction' is the right word).

But thanks for that enlightenment, Adam.

I believe the Joint European Torus broke even on power input-output a year or so back as well. It's quite an impressive project.

Broke? You mean physically because of energy overload?

I just can't imagine how anything could contain that kind of energy...

Adam means 'break even' as in the power in equalled the power out. JET has been running for many decades and all previous attempts to get Fusion working resulted in more power in than was produced.

In a way, we know how to control and make fusion work. Unfortunately you need a star to do it.

:) Thanks for clearing that up, thed.

But what i was thinking is that you cannot contain a star.

A little (11.2 MB) PDF file from that JET place.

The Science Of JET (http://www.jet.efda.org/documents/wesson/scienceofjet.pdf)

That looks fat.