taken from that other thread:


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 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."""

An observer outside the boat will be happy to tell you if it is moving or not.

This prinicple of relativity in regard to FOR's has been mistakenly seen as representing a scientific principle. It is not. It is a prinicple that is based on a variable, ie INFORMATION, and nothing else. It has nothing to do with how Nature works.

There is still no absolute FOR needed if there is no aether out there. Each situation simply has to be looked at in a different way.

If we are all inside the boat and nobody is outside to tell us the situation we're in, then we shouldn't be making up silly principles because we lack information. We should simply understand that science requires the factor of Observation but that the Observer is limited in his capibilities.

An observer outside the boat will be happy to tell you if it is moving or not.

Unfortunately, the observer outside the boat cannot tell you *absolutely* if the boat is moving across the water or if the water is moving under the boat.

"""Unfortunately, the observer outside the boat cannot tell you *absolutely* if the boat is moving across the water or if the water is moving under the boat."""

Luckily we know how waves of the ocean work (quite complex if I'm not mistaken). Both the boat and the waves are in motion.

Luckily we know how waves of the ocean work (quite complex if I'm not mistaken). Both the boat and the waves are in motion.

You're missing the point. The outside observer cannot tell whether the boat is moving and the ocean, the Earth, the Solar System, and the Galaxy are *absolutely* stationary or whether the boat is *absolutely* stationary and the ocean, the Earth, the Solar System, the Galaxy are moving underneath it.

It has nothing to do with how waves work.

Q,

What you refer to as "relativity" I see as simple inertia.

Inertia: The tendency of a body to resist acceleration; the tendency of a body at rest to remain at rest or of a body in straight line motion to stay in motion in a straight line unless acted on by an outside force.

Regardless of the speed of an object, the object will continue moving at that constant speed, and in a straight line. This explains why the observer can't tell if the ship is moving or not. It has nothing to do with Einstein or the Theory of Relativity.

Also, you, Crisp, and others on this forum are constantly claiming that the mass of an object increases as it speeds up. If that were the case, then the observer could find the true speed of the ship by measuring it's increased gravitational field. In other words, the observer's weight is dependent on the speed of the ship.

Funny, it appears that Einstein contradicted himself, again.

Tom

Prosoothus

Actually the conversation between cest moi and myself is in regards to frames of reference. I don't know how you managed to read any differently, but somehow you did. :bugeye:

Q,

My post must have been misunderstood. I was stating that the reason the observer in his frame of reference could not tell if the ship is moving or not, is the result of the nature of inertia.

Tom

You're missing the point. The outside observer cannot tell whether the boat is moving and the ocean, the Earth, the Solar System, and the Galaxy are *absolutely* stationary or whether the boat is *absolutely* stationary and the ocean, the Earth, the Solar System, the Galaxy are moving underneath it.

I'll tell you a little secret ;) You are the one who keeps missing the point. The observer is LIMITED. You cannot, read CANNOT, make this LIMITATION into a PRINCIPLE of NATURE

(and you can take the bottom of the ocean as a reference to see if the boats is moving and obviously it IS ALWAYS moving cause the water surface is never at rest -> absolute rest is a phantasy)

"""The outside observer cannot tell whether the boat is moving and the ocean, the Earth, the Solar System, and the Galaxy are *absolutely* stationary or whether the boat is *absolutely* stationary and the ocean, the Earth, the Solar System, the Galaxy are moving underneath it."""

they are not moving underneath it
the ocean and the boat are in the momentum of the earth
and the earth in the momentum of the galaxy
if I am walking in a train you won't tell me if I am the walking in that direction or I am standing still and the train is moving
OBVIOUSLY the train is ALSO moving at that moment, but as I have its momentum with me its motion is COMPLETELY irrelevant as to where I am walking

You're boat analogy is carefully chosen to be falsifiable.

It is better to generalise the analogy. Are you stationary? Can an outside observor determine your real FOR or would their FOR determine the observation.

There are two obvious answers. Yes or no. If you chose a third, being 'it depends', you ubnderstand Relativity.

Thed, why don't you answer more directly to my statement?

""You're boat analogy is carefully chosen to be falsifiable. ""

I picked it because it is from Galileo
need I say more?
btw, it is excellent to test it
it appears to be wrong logic
pick out any scenario
it's never logic
it's fundamentally wrong

""It is better to generalise the analogy.""

not really, every situation is different
you should answer the boat scenario
or even the train scenario

generalisations have the bad smell that YOU can generalise some kind of principle and make it look REALISTIC but when put to practice it turns out it isn't (see also the "throwing-a-baseball-scene in regard to kinetic energy in that case; note also that the relativity principle in EVERY experiment is a one-way conclusion, it has never been tested in both ways to see if it's true and I don't even think we can put up an experiment to test it and in other words, it's not even science because it is not falsifiable as per Popper)

""Are you stationary?""

"""Can an outside observor determine your real FOR or would their FOR determine the observation.
There are two obvious answers. Yes or no. If you chose a third, being 'it depends', you ubnderstand Relativity."""

If you want to you can pick a 4th, a 5th or a trillionth observer. It still doesn't turn it into a basic principle of nature. If you look at a particular situation, you need to look at what the observer KNOWS or can see. If he doesn't know, then so be it. Nature is not some kind of quiz where you HAVE TO say yes or no when you don't know. Saying it depends is the answer of wrong logic and fooling yourself by thinking you have solved the problem. You haven't.

c'est moi:

Obviously you still do not understand the principle of relativity.

<i>...you can take the bottom of the ocean as a reference to see if the boats is moving and obviously it IS ALWAYS moving cause the water surface is never at rest...</i>

Consider this:

The boat is moving at 3 m/s across the water.
The water is moving at 2 m/s across the ocean floor.
The ocean floor is moving at 1000 km/hr around the centre of the Earth.
The centre of the Earth is moving at 29 km/second around the sun.
The sun is moving at 200 km/second around the centre of the galaxy.
The centre of the galaxy is moving relative to the local group of galaxies.
The local group is moving relative to other galaxies in the universe.
We can't determine if the universe is moving, since there's nothing to compare it to.

So, we cannot calculate how fast the boat is moving in an absolute sense. The best we can do is to say how fast it is moving with respect to the water, or the ocean floor, or the sun, or a small planet orbiting Tau Ceti or whatever.

All motion is relative to an observer.

James R, I have to catch my train now but with all respect, you don't even understand what I am trying say -> do I say I want an absolute frame??????? (btw, it took you many posts in regard to the Sagnac experiment to get to the bottom of it, ie the earth is a non-inertial frame because we DO detect its absolute motion but it doesn't matter 4 rel. cause its non-inertial)

you on the other hand as the rest can't even answer to my objection on this stupid principle on relativity

I had a new thought this night and appears that this silly principle is violated by physicists all the time (ie, they measure/caclculate kinetic energy --> but that's for this evening or maybe tomorrow)

so, has anyone here even the descensy to answer me?

Out of everyone here, I'm probably one of the least educated in physics, but this is what I see.

As the Sagnac (if it's the one I think it is) and other experiments demonstrate, regardless of emitter movement or observer movement or any other factors, light (ie. photons, or EM emissions, of any part of the spectrum) travels at a given speed in any given medium. Like sound from a source arriving at two different observers in different places at different times, so light will arrive at different observers at different times. This does not indicate time travel or any other spooky things, it indicates only speed and distance.

When on a ship, if that ship measures its speed as 30 knots, then it is not necessarily travelling at 30 knots relative to the Earth, or relative to its geographical position. You must take into account the current and such. If there is a 5 knot current going the other way, the ship's instruments may read 30 knots but it will only be travelling at 25 knots relative to the Earth. Relative to an observer off the ship, well, it depends on the movement of the observer too. And the ship's speed is different again relative to the Sun, to the Moon, to Jupiter, and to Andromeda.

Not only is there no defined stationary point or direction in the universe against which we can measure absolute velocity, there is no need for such. When you get right down to it, you simply don't need such a reference. All you really need is velocity between yourself and whatever objects/effects you give a damn about, such as other ships nearby, the stars, et cetera. We already know light travels at certain speeds in certain media, although the details of the numbers may be refined furtehr in future; and we know how long it will take to walk from here to the corner shop, regardless of how we are moving in relation to Andromeda. Maybe relevent motion is as important as relative motion.

C'est Moi, sorry if this is not what you were wondering about, I just thought I'd spill some of my thoughts.

A very well thought post. Congratulations.

C'est Moi I am trying to make you think differently, is all. Galileo was right in his day, and still is in the limits of low velocity. What he said was absolutely correct based on common sense and a lack of knowledge of very high velocities and the wider Universe.

You seem to be deliberately ignoring the point James R, and myself in a differing style, are trying to get over. Adam's take on it is very wel stated as well. Let me put it this way.

Am I stationary, obviously yes. But only in respect to the Earth. To use the more prosaic language, in the FOR of the Earth I am stationary. But that is an arbitrary choice. If I choose my FOR to be the Sun, I am anything but stationary. From another Star I am not stationary. You can scale this out as far as you want. In every other FOR I am moving along differing velocity vectors. In the FOR of a very distant galaxy and a putative observor there, I am moving at a significant fraction of light speed.

The choice of my zero point is totally arbitrary. The speed of a boat across the ocean is 10 knots say, as measured by a stationary observor on the shore. But as measured by an observor stationary with respect to the Sun, say, that boat is travelling at hundreds of Km/h. Who is correct then?

Let me put it another way.

Can we measure our real velocity through space? In order to do this you have to measure velocity with respect to a fixed point. Any point you choose is itself moving through space. So all you need do is work out the other things velocity through space. But what do you measure it with respect to. We're moving, it's moving, every moves with respect to every thing else. Movement is relative.

If you put two astronauts into two ships moving at identical velocities and parallel to each other, they can not determine their velocities. Eventually they may realise the 'fixed stars' are moving so they can measure against that. Once they realise the stars are moving they no longer have a zero point to measure against.

There are no absolutes all is relative, hence Relativity.

Holy shit! Forgot to realise that bit, you might say. Someone far enough away may, in relation to me, be moving at whopping great speeds, as Thed said some significant fraction of C. Meanwhile to them, they are only walking about one metre per second toward the corner shop. No big deal to them maybe, but a totally different story for me.

Now whether that person is moving at one metre per second toward his corner shop, or moving at 1/2 C across a distant point in the sky from my perspective, light still retains its own speed. For all I know that distant galaxy's relative motion to us might possibly exceed C, but that's beside the point. I think therefore that "lightspeed" and "light" can be disregarded from further consideration in this matter or relative motion. We already know light is going a certain speed, no need to worry about that particular piece of information further for the moment.

That leaves some daft punk on Hoobagoo Prime wandering toward his corner store at 1m/s, and also travelling at ludicrous speed. So we have two speeds to consider in this situation. Only two which are relevent anyway.

So after all that, it seems to me that the discussion must make a declaration that lightspeed (the speed light travels, referring only to that) is something to be discussed separately from considerations of relative motion. Relative motion may or may not have anything to do with C, may or may not involve speeds greater than C, et cetera, so we can ignore C when discussing relative motion.

Small example: Two torch beams shining directly away from each other. Relative motion is double C, I would think. C is still C, but relative velocity is double C.

And that, by the way, it seems, might lead to discussion of an absolute measure of speed: just C, the passage of EM signals through whatever materials. I don't know if the energy/activity of a material has effects on the speed of light through it (for example I don't know if the temperature of air affects how fast light passes through it), but if there is a difference, then C may be relative to the motion of particles blah blha blah. But in any case, even if there is some absolute measure of speed which can be used, it still makes no difference to the relative motion of, well, anything, such as me and that dude on Hoobagoo Prime.

you all keep staring your eyes blind on the concept of absolute FOR

and that's NOTTTTT what it is about

so again Thed, if you want to, you can now answer my statement against the principle instead of playing around with absolute or not

I have the feeling you all deliberitly don't want to answer the point I have made and which I won't repeat

I agree with you Adam, what is relevant is important, the rest is peanuts

I see Crisp has mentioned something about kinectic energy which I wanted to point out now

example: I throw my basball away up in the sky

using the rel. principle: or it is the ball which is going up away from the earth or it is the earth which is moving away from the earth, no preferred FOR

--> we do, however, speak in terms of measuring the kinetic energy of that ball which has been provided by your arm

BUT, from the other point of view, it is the earth who is flying away, at let us say 60 miles/hour
obviously, the earth must aquire kinetic energy seen from the FOR of that ball

now two remarks:

1) the energy has been provided by my body and transferred to that ball (I believe Crips made a comment on this in regard to particle acceleraters, maybe the solution is easy)
and didn't go to the earth
where does the earth get its kinetic energy?
and where did the energy of my arm went if it didn't went to that ball as kinetic energy? (we are seeing all this now from the FOR of the ball)

2) the very thought that we speak about measuring or calculating kinetic energy of a moving entity from our FOR is against relativity

Let me make myself clear:

Someone with an atomic clock is moving at an important fraction of the speed of light and passes by us.

what does relativity has to say on this:

--> From our FOR his clock runs slower
--> From his FOR our time (clock) is running slower

This is a direct consequence of the pr. of rel. as it doesn't allow you to say that the other one is moving. It depends. A third, imaginary observer is dragged in this and he'll tell you it depends.

Big consequence is: You CANNOT say: 'Hey, that guy with his clock is moving at such a great speed so his clock must definately be influenced by this great speed and must be absorbing an important amount of Kinetic energy which would influence the atomic levels of that atomic clock explaining why it slows down.'

BECAUSE, it depends which FOR you take, you are not allowed to think like that. That guy with his clock may be stationary and it is YOU who is moving at an important fraction of the speed of light so you CANNOT explain this slowing down of his clock due to kinetic energy.

But on the other hand, it seems to be common to speak about kinetic energy of a moving object or entity such as a particle which has been accelerated or as a ball which you throw away. There, it is allowed to speak of kinetic energy INFLUENCING that entity. BUT when talking about clocks moving at high velocity, suddenly, you are not allowed to consider the effects of absorbed kinetic energy (or even gravitational energy) and you are not allowed to explain time dilation nor lenght dilation as a logic consequence. Instead, you have to use the magic of FOR's which is clearly not a true principle of Nature but a fairy tale.

What exactly is your objection. Your descriptions of your objections appear to have many unwritten asumptions about what you understand something to mean and what you mean. A clarification may be in order.

For the moment I will address what I think you mean in the OP.


"""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."""

An observer outside the boat will be happy to tell you if it is moving or not.

But only with respect to that observor. Another observor in another frame will see things differently. The point of transformation equations is to ensure a consenus of agreement can be reached. The Galilean Transform does not work at high velocities and it breaks Maxwell's equations.


This prinicple of relativity in regard to FOR's has been mistakenly seen as representing a scientific principle. It is not. It is a prinicple that is based on a variable, ie INFORMATION, and nothing else. It has nothing to do with how Nature works.

To be blunt, I am not sure what you mean by <i>This prinicple of relativity in regard to FOR's has been mistakenly seen as representing a scientific principle</i>. All relativity does is take the Lorentz transform, assumes the speed of light is invariant beteen frames and that you can't distinguish between inertial frames.

Which of these do you object to and why? Or are we on about General Relativity which says there is no special intertial frames (no absolute rest) and the Principle of Equivalence.

I think this is what we are disagreeing on though:-

In the Galilean transform you can have absolute rest and absolute time. In the Lorentz transform you can not. Time and Space become intertwined entities. I suspect you are trying to argue that the Lorentz equations are mathematically right but the Galilean interpretation is right.


There is still no absolute FOR needed if there is no aether out there.

This is an apparent non-sequitor. You are arguing about Relativities interpretation of frames of reference and not an Aether. I'm glad you agree there is no absolute FOR for no Aether. There is no aether ergo no absolute frame of reference, as relativity says.


Each situation simply has to be looked at in a different way.

Yep, it's transform equation. Which leads to Relativity.


If we are all inside the boat and nobody is outside to tell us the situation we're in, then we shouldn't be making up silly principles because we lack information. We should simply understand that science requires the factor of Observation but that the Observer is limited in his capibilities.

But there is no outside the boat in the Universe. It is a self contained system. Assuming we both mean Universe to include all of creation rather then universe being only what we can see with the possibility of other universes comprising the Universe.

Just read your last post. I see where you are coming from now. But I'm for home. Catch you later.

Adam

I believe you are beginning to get a grasp on Relativity. A couple of points:

The speed of light is important because it is the one constant that can be relied upon. Although you cannot say for sure what speed the daft punk on Hoobagoo Prime is moving, ie. one meter per second or half the speed of light, you can however know that the speed of light is measured in all inertial reference frames. That is what Special Relativity is all about.

Secondly you cannot add relative velocities together, as in those near the speed of light because the relative velocity of any two objects never exceeds the velocity of light. You may add the speed of two cars traveling towards one another, for example; A is traveling 90 miles per hour towards B who is also traveling 90 miles per hour towards A. Their combined speeds are 180 miles per hour.

However if A is traveling .9 the speed of light towards B who is traveling also traveling .9 the speed of light towards A, you cannot say their combined velocities are 1.8 the speed of light. This is due to the fact that length and time are different in different reference frames, especially when approaching these relativistic velocities. Instead we use the Relativistic Addition of Velocities:

v = (v' + u)/ [1 + (uv'/c2}]

where v is the proper velocity (at rest)
v' is the velocity of the object at velocity u

Plugging in .9 the speed of light we get:

(1.80/1.81)c = .9945c which is still less than the speed of light.

:)

"""Just read your last post. I see where you are coming from now. But I'm for home. Catch you later."""

indeed, because from your response I still see that you are thinking on a different thing than me

what I mean is what I have said

I don't know how I have to say it to be more clear

you might want to read the piece where this discussion started with James R in "mass=energy"

Originally posted by c'est moi
I see Crisp has mentioned something about kinectic energy which I wanted to point out now

example: I throw my basball away up in the sky

using the rel. principle: or it is the ball which is going up away from the earth or it is the earth which is moving away from the earth, no preferred FOR

--> we do, however, speak in terms of measuring the kinetic energy of that ball which has been provided by your arm

BUT, from the other point of view, it is the earth who is flying away, at let us say 60 miles/hour
obviously, the earth must aquire kinetic energy seen from the FOR of that ball

Absolutely right.

The first time people see this they generally feel reality shift to the left a little. It sounds ludicrous and it is.

The thing to realise is that special relativity only holds for intertial frames. The ball has accelerated from rest to some speed. Therefore no inertial frame. The ball gains energy.

If this was an inertial frame another thing happens, as you've realised. The amount of energy the Earth would gain appears to be the same of as the ball gets, absolutely negligble for the Earth but a lot for the ball. But in reality there are no real inertial frames. The idea is a simplification, compared to General Relativity, designed to further understanding of how things really work.

Special relativity helps us further our understanding that the Universe is not as simple as Galileo and Newton believed.


now two remarks:

1) the energy has been provided by my body and transferred to that ball (I believe Crips made a comment on this in regard to particle acceleraters, maybe the solution is easy)
and didn't go to the earth
where does the earth get its kinetic energy?
and where did the energy of my arm went if it didn't went to that ball as kinetic energy? (we are seeing all this now from the FOR of the ball)

It is probably more fair to say the person throwing the ball gains in energy. But again, the ball has accelerated so SR does not hold.



2) the very thought that we speak about measuring or calculating kinetic energy of a moving entity from our FOR is against relativity

Let me make myself clear:

Major snippage



In an ideal, perfect world of constant velocity only this confusion should happen. As you point out it is possible to work out who is really travelling faster. The trick is that you have to sit down and work that out. What students spend a lot of time doing is solving deliberately contradictory problems to see if they can work out which FOR is the best one to solve the problem in.

I hope that helps clear a bit of the mess up without it sounding lke a major kop out. One of the problems when trying to explain this is that everyone falls back onto the standard explanations where they suddenly saw the light for themselves, expecting others to see the light for themselves.

okay, if these were inertial frames I would have knocked down relativity

- tell me why relativity only holds for inertial frames
- what, then, are indeed inertial frames (cite some examples)
- also, tell me what happens in regard to the observer with his clocks, i.e. he has been accelerated yet relativity is used there with time dilation as a result. He is just like the ball which has been thrown away.

Originally posted by c'est moi
okay, if these were inertial frames I would have knocked down relativity

You wish :)

If the Universe contained nothing but two observors moving at two differing yet constant velocities all they can work out is the difference in velocity. But the Universe is vastly more complex than that. Most things are at rest with respect to light, in their own frames, you need some seriously wierd conditions to get two observors, travelling near light speed, to compare conditions. This is where high energy Astrophysics comes in as a serious test of Relativity. In reality light travels at light speed, we are effectively stationary.

The trick is knowing where to ignore affects, like our motion with respect to a far distant observor.


- tell me why relativity only holds for inertial frames

It's an assumption, an axiom, of Special Relativity. General Relativity holds for accelerating frames.

All that is required is that the derived results of those assumptions be shown to be wrong for Einsteins ideas to be knocked down. So far they have held.


- what, then, are indeed inertial frames (cite some examples)

Simply put, a frame moving with constant velocity.

But in the real world most frames, observors, are in gravitational fields so feel acceleration. They are non-inertial frames. Normally the gravitational field is so weak it can be assumed to be an inertial frame though. In physics this is referred to a Lab frame. Your measurements are taken over a small enough scale the affects can be ignored.

As I say, for every day events Galilean transforms hold. Only when the other frame is moving signicantly faster than you, near light speed, compared with your stationary frame, does Special Relativity hold.

I suppose that is the big thing. The relative speed has to be huge, us 'stationary' and the object near lightspeed compared to us for Relativity to be invoked.


- also, tell me what happens in regard to the observer with his clocks, i.e. he has been accelerated yet relativity is used there with time dilation as a result. He is just like the ball which has been thrown away.

Same thing I suppose, if the two observors have a huge velocity difference, the higher one has a larger time dilation compared to the lower one. Technically, if you have two observors at light speed they see the same thing, no time dilation between them.

Hope that helped.

Just realised something. The whole point of Relativity is the difference in velocities.

The way I personally look at it is that light speed is the base line and you calculate effects based on your difference to that. To all affects and purposes if I throw a ball into the sky it only has kinetic energy KE= 1/2 mv^2, it's speed is not enough to take SR into account. Strictly speaking you should but the afects are so small you can not measure them. Only for a near light speed particle is the effects significant, compared to us.

Of course, there are complicating factors such as strong gravitational fields and large distances. Again, the invariance of light speed is taken to be a local affect. Local being the scale of the Uinverse. But if you have something 12 billion light years away in a strong gravitational field these simplistic assumptions of SR just do not hold.

I've gotta say, I can't yet see one point in this.

If you shine torches in directly opposite directions, one in each hand, away from you, the light is shooting off ine either direction at C. The distance between the leading edges increases at a rate of twice C. I can not see how that would be otherwise. C remains a constant, but their relative motion seems double C to me.

c'est moi:

Let's take a look at your baseball throwing example.

<i>using the rel. principle: or it is the ball which is going up away from the earth or it is the earth which is moving away from the earth, no preferred FOR</i>

Either point of view is fine, but it turns out to be MUCH easier to take the baseball to be moving. The reason is that in that case the Earth can be taken to be an <b>inertial</b> frame of reference. An inertial frame of reference is one which is moving with constant velocity and not accelerating. The Earth actually accelerates a tiny bit when you throw the baseball, but we can ignore that because the Earth is so much more massive than the baseball. On the other hand, the baseball's reference frame is definitely non-inertial. It accelerates constantly throughout its motion. That complicates the analysis considerably, as I will explain below.

<i>we do, however, speak in terms of measuring the kinetic energy of that ball which has been provided by your arm

BUT, from the other point of view, it is the earth who is flying away, at let us say 60 miles/hour obviously, the earth must aquire kinetic energy seen from the FOR of that ball</i>

Yes, that is true. Which leads to your difficulties...

<i>1) the energy has been provided by my body and transferred to that ball...and didn't go to the earth where does the earth get its kinetic energy?</i>

Let's be very careful with reference frames. In the Earth frame, the energy of your arm was transferred to the ball, which therefore acquired kinetic energy. In the reference frame of the ball, the energy of you arm was transferred to the Earth, which acquires kinetic energy.

In the reference frame of the Earth, the only forces acting on the ball are your arm throwing it and gravity pulling it down. But in the ball's reference frame things are different. We have you arm throwing the Earth away and the ball's gravity attracting the Earth back to it. But, because the ball's reference frame is non-inertial we also see an inertial force due to the reference frame, which accelerates the Earth more rapidly than we would otherwise expect. This force initially helps accelerate the Earth away from the ball, then it changes direction to help accelerate the Earth back towards the ball. The force is real from the ball's point of view, but imaginary from the Earth's point of view. It can be shown to arise solely due to the change of reference frame.

Without the extra inertial force, the principles of conservation of energy and momentum do not hold in a non-inertial reference frame. That is why relativity is formulated in inertial reference frames.

Therefore...

<i>2) the very thought that we speak about measuring or calculating kinetic energy of a moving entity from our FOR is against relativity</i>

is wrong. You can do it if you like, but you have to be careful.

Now to your further comments.

<i>Someone with an atomic clock is moving at an important fraction of the speed of light and passes by us.
what does relativity has to say on this:
--> From our FOR his clock runs slower
--> From his FOR our time (clock) is running slower</i>

That's completely correct. You conclude from that:

<i>...you CANNOT explain this slowing down of his clock due to kinetic energy.</i>

Again, that is correct. The slowing of the clock is due to the different reference frames only.

<i>BUT when talking about clocks moving at high velocity, suddenly, you are not allowed to consider the effects of absorbed kinetic energy (or even gravitational energy) and you are not allowed to explain time dilation nor lenght dilation as a logic consequence.</i>

You can consider energy if you like, but energy is relative. Time dilation and length contraction are not due to changes in energy. They are due to changes in reference frame.

<i>Instead, you have to use the magic of FOR's which is clearly not a true principle of Nature but a fairy tale.</i>

I find it surprising that you are so ready to criticise relativity when it is clear that you do not understand it. Before you can say what is wrong with a theory, you need to know what the theory says.

"""It's an assumption, an axiom, of Special Relativity."""

The axiom arised because it is based on the constant speed of light (hence no acceleration)?

+

has ANYONE an idea how it is possible that photons are not influenced by the speed of the frame from which they have been emitted

photons have moment, right? the atom is moving at 100 km/h and emits a photon forwards
how is it possible for the photon which HAS momentum not to absorb the momentum of the atom? Any idea?

"""All that is required is that the derived results of those assumptions be shown to be wrong for Einsteins ideas to be knocked down. So far they have held."""

I have the feeling that the only thing that FOR's stuff does is complicate things where it can be done more easily. See further.

"""I suppose that is the big thing. The relative speed has to be huge, us 'stationary' and the object near lightspeed compared to us for Relativity to be invoked."""

and,

"""Same thing I suppose, if the two observors have a huge velocity difference, the higher one has a larger time dilation compared to the lower one."""

1) and any gravitational effect can be ignored than?

2) can also be ignored the fact that the object is accelerating towards C and does not have a constant velocity?

"""Either point of view is fine"""

Thed said that SR does not apply here.

"""but it turns out to be MUCH easier to take the baseball to be moving."""

maybe you should consider the possibily that ONLY the baseball is moving as a consequence of me throwing it away
that's what I mean when I feel FOR's stuff is complicating things which are already complicated as they are

''''"In the reference frame of the ball, the energy of you arm was transferred to the Earth, which acquires kinetic energy."""

in concrete terms, how was the energy transferred to the earth and not to the ball?

"""In the reference frame of the Earth, the only forces acting on the ball are your arm throwing it and gravity pulling it down. But in the ball's reference frame things are different. We have your arm throwing the Earth away and the ball's gravity attracting the Earth back to it."""

and this is where FOR's become silly: I have to believe that my arm throws the earth away
moreover, aren't you wrong here? after all, Thed said that SR does not apply to this scenario because that ball is accelerating all the time

"""But, because the ball's reference frame is non-inertial we also see an inertial force due to the reference frame, which accelerates the Earth more rapidly than we would otherwise expect. This force initially helps accelerate the Earth away from the ball, then it changes direction to help accelerate the Earth back towards the ball. The force is real from the ball's point of view, but imaginary from the Earth's point of view."""

it is imaginary
look, I trow the ball let us say 20 metres in the air, or no even more , i'm strong and I throw it 150 metres in the air
Now, I have to believe that from the FOR from the ball that my arm has trown away the earth 150 m in the opposite direction
Believe me, this doesn't happen.

"""It can be shown to arise solely due to the change of reference frame."""

it cannot be shown because I said earlier, SR has only been tested in a one-way direction
the rest happens in the minds of scientists

"""Without the extra inertial force, the principles of conservation of energy and momentum do not hold in a non-inertial reference frame. That is why relativity is formulated in inertial reference frames."""

I see

"""Again, that is correct. The slowing of the clock is due to the different reference frames only."""

Which explanation should be favoured, one which gives a fairly simple reason like increase in kinetic energy or one which basically toys around with FOR's with no physical explanation? Which one deserves to be favoured by Occam's razor? Which one needs to be favoured, the one which claims both ways are equal but has only been tested in one way or the one which cuts the imaginary frame away and can succesfully be confirmed in every single experiment (lorentz equation are correct)?

"""You can consider energy if you like"""

indeed, I like that more

"""I find it surprising that you are so ready to criticise relativity when it is clear that you do not understand it. Before you can say what is wrong with a theory, you need to know what the theory says."""

i feel that after these discussion I do know what it says
it says everything is relative :D
it moves you around in frames explaining that no effect is actually real like real for everyone but just side effects of your perception
in that way it creates an explanation which does not even try to explain the effects as result of mechanisms in nature
I feel the latter deserver to be favoured unless it can be shown that SR is real in both ways instead of keeping the other way imaginary

Heck, even I know why photons (measurement units of EM signal) have a given speed regardless of the motion of the emitter (I think I do anyway!). Light is a propagation of EM energy through space/matter. That propagation depends on what it is travelling through. Change the medium, the speed of propagation changes. But the light itself does not change depending on the medium or the emitter. Why?

I used an analogy a while ago, involving running in water. If you run at your full speed in water, you basically run at your top speed reduced by the material of the water dragging on you. Light=runner, space=water. If you jump out of a car speeding along the beach and land in the water and run, you will still only be able to run at that running-in-water top speed. The motion of the car won't change that. (You have to ignore the little bit of time from jumping out of the car to running in the water.)

The running in water is based on your size and cross-section and friction and all, and in particular on the amount of energy you apply and the water as well. Similarly, light propagation is based on the energy involved (runner) and the material (water). The light will not be able to move faster if the torch it comes from is hurtling along the beach in a car.

The propagation of light depends only on the energy involved and the space/material it is passing through. Or at least that's how it seems to this uneducated person. :p

"""If you jump out of a car speeding along the beach and land in the water and run, you will still only be able to run at that running-in-water top speed. The motion of the car won't change that. (You have to ignore the little bit of time from jumping out of the car to running in the water.) """

you example is insisting that photons move true a medium

+

how do you explain with your example that momentum is not conversed in regard to photons

Sorry, I can't explain that at all. I have not studied this stuff enough to know anything about conservation of momentum and such. I'll get around to it some day...

c'est moi:

<i>maybe you should consider the possibily that ONLY the baseball is moving as a consequence of me throwing it away
that's what I mean when I feel FOR's stuff is complicating things which are already complicated as they are</i>

Can you give me a test which will tell me whether it is really the baseball or the Earth which is moving? If not, then either point of view is equally good.

<i>in concrete terms, how was the energy transferred to the earth and not to the ball?</i>

Newton's third law says for every force there is an equal and opposite force. Therefore, when you exert a force on the ball to throw it, the ball exerts an equal force on you in the opposite direction. That reaction force causes you to accelerate, taking the Earth with you (since you're standing on it).

<i>and this is where FOR's become silly: I have to believe that my arm throws the earth away moreover, aren't you wrong here? After all, Thed said that SR does not apply to this scenario because that ball is accelerating all the time.</i>

Ignore whether SR appies or not and use your common sense. What do you see from the ball's point of view? You see the Earth moving away. Therefore, something must cause it to move away. That requires a force, and that force can only come from your arm.

<i>Now, I have to believe that from the FOR from the ball that my arm has trown away the earth 150 m in the opposite direction
Believe me, this doesn't happen.</i>

Why not? If you say it doesn't happen you need a reason for that belief other than just your gut feeling.

<i>Which explanation should be favoured, one which gives a fairly simple reason like increase in kinetic energy or one which basically toys around with FOR's with no physical explanation?</i>

A FOR is a physical explanation. And your kinetic energy arguments do not cut the mustard, whereas relativity has been rigorously tested and shown time and again to work.

<i>...it moves you around in frames explaining that no effect is actually real like real for everyone but just side effects of your perception</i>

No, that's not true. Effects are real. Certain physical quantities are invariant in different reference frames. It's just that you insist on looking at quantities which vary in different reference frames.

<i>I feel the latter deserver to be favoured unless it can be shown that SR is real in both ways instead of keeping the other way imaginary</i>

SR is real in "both ways". It has been tested.

"""Can you give me a test which will tell me whether it is really the baseball or the Earth which is moving? If not, then either point of view is equally good."""

From the point of view from the ball, if that baseball has brains, it will think "Aha, I am the one flying away from the earth".
It seems that all of you assume that once you take the FOR of something, that that's the one who should be regarded stationary and the other one moving. That's absurd. In fact, both are moving. The earth around the sun and the ball away from the earth.

Further, can you provide me an experiment that will affirm me that the universe is not mere a dream or an illusion. I guess you can't do that so now everybody has to accept that everything is an illusion....

That's also a problem with relativity, and I will say this again and again, it can only be tested in one way. Further, imagine you fly away with that ball with all the equipment that you can imagine. what will you be able to do in order to see if it is really you who is moving? What is there to measure? Aah, you say it yourself, no experiment can be found for this ... what does this mean, IT MEANS THAT WITH THE PRINCIPLE NO FALSIFICATION IS EVEN POSSIBLE ... Popper is looking really really mad here.

"""Newton's third law says for every force there is an equal and opposite force. Therefore, when you exert a force on the ball to throw it, the ball exerts an equal force on you in the opposite direction. That reaction force causes you to accelerate, taking the Earth with you (since you're standing on it)."""

When I push against a wall and I push so hard that I get through it with my arms, then the bricks are falling out on the ground on the other side. It is not the earth and me who are falling up. If so, we all should feel this on earth. If the earth is flying away 150 metres from the baseball, everyone should feel this. Teuuuuuuuut teeeeeeeuut::: let me correct myself: we cannot feel this because that is the way it is for those bricks and that wall. Not for us....... Silly old me. ---> no falsification is possible (this is really striking me and hopefully you also).

"""Ignore whether SR appies or not and use your common sense."""

I can't do that if I believe in SR principle.

"""What do you see from the ball's point of view? You see the Earth moving away. Therefore, something must cause it to move away. That requires a force, and that force can only come from your arm."""

You see that YOU leave the earth BEHIND. Bye bye earth. "I am moving also from my point of view", that's what you think. I realise this. Wow. Going fast here ........ ........... weeeeehaaaaaaaaaaaaa!!! Oeps, something has happened: Everything went dark ..... what to do? The only things I can see is my own body and the earth. Oh my God!!, no reference is possible: Who is moving??? All my information has been taken away. Well, let's not get silly and panick here and let us realise that without more information I'll not be able to tell who is moving.

"""Now, I have to believe that from the FOR from the ball that my arm has trown away the earth 150 m in the opposite direction
Believe me, this doesn't happen.

Why not? If you say it doesn't happen you need a reason for that belief other than just your gut feeling.""""

I'll tell you something new here (haha), falsification is not possible and that's why. I also tell you, there's some pink elephants walking around here in my room. the problem is that you can only see them if you are here in my room. If you are outside the room, you can't see them. that's not all: If you come in my room to look at them, they'll be outside the room and again, you won't see them. You have to go outside the room for that ..... you know the rest don't you?

"""A FOR is a physical explanation. And your kinetic energy arguments do not cut the mustard, whereas relativity has been rigorously tested and shown time and again to work. """

it seems to me that you are not following here: EVERY test that has been tested to test relativity has been testing it in ONEEEEEE WAAAAAAAAY. (btw, one way). And every single test also confirms that these effects can be due to kinetic energy or grav. energy. That is the mechanism where falsification is possible. But as it seems to agree with all experiments so far, it seems to be correct. We simply cut away the other FOR of reference because

1) it is not even usefull to us
2) no falsification is possible

Simply --> Lorentz equations remain, intepretation lil different and the mechanism behind the changes is explained (you can look up the papers of Marmet, it agrees fully with what we see, the only thing that is different is the mechanism behind it)

"""...it moves you around in frames explaining that no effect is actually real like real for everyone but just side effects of your perception

No, that's not true. Effects are real. Certain physical quantities are invariant in different reference frames. It's just that you insist on looking at quantities which vary in different reference frames."""

sometimes you should read something twice, ie I say "no effect is actually real <<like real for everyone!!>>

"""SR is real in "both ways". It has been tested."""

In your dreams apparently. One way. Not two ways. Two ways is impossible as the Pink elephants (read 'the principle itself') show us.

I guess you've flied on an electron at 99,999 % of c and that whilst going so fast, you've actually been able to see that my clock down there was going slower. Moreover, you felt nothing special at that speed because we are taking you as a FOR here and the rule says: The one who is taken as FOR must be the one who is regarded stationary. Moreover, you've not accelerated at all. Yep, that's right. You went all the way up to 99,9 % of c without acceleration. Indeed, relativists regard you as an inertial frame.

I'll tell you what happens when you go so fast:

First of all, you'll get the effect like looking at the wooden beams connecting the railways --> when the train goes fast, you'll be able to see each individual, but when it goes 80 km/hour you'll see all of them like one piece
If you go even more faster on that e-, you practically see nothing: just colours and shapes, maybe not even shapes
if you're not dead already, you'll realise that you're going fucking fast, everything will flash before you eyes, it would be like madness ... and this sightseeing of yours won't change wether you're stil accelerating or not.
if you fly with an airplane at a few Mach's without accelerating, you still won't be able to count any of those wooden beams if you'd fly over them. you'd be able to walk around without falling but that's all.

up

c'est moi:

I asked: <i>Can you give me a test which will tell me whether it is really the baseball or the Earth which is moving? If not, then either point of view is equally good.</i>

You replied: <i>From the point of view from the ball, if that baseball has brains, it will think "Aha, I am the one flying away from the earth". ... It seems that all of you assume that once you take the FOR of something, that that's the one who should be regarded stationary and the other one moving. That's absurd.</i>

So, I take it your answer is "No, I can't give you any test which can distinguish between the baseball moving or the Earth moving." It's just your gut feeling that's driving your argument - nothing more.

<i>Further, can you provide me an experiment that will affirm me that the universe is not mere a dream or an illusion. I guess you can't do that so now everybody has to accept that everything is an illusion.... </i>

No. The correct conclusion to draw is that the universe <b>might</b> be an illusion. But since that fact would have no impact on our perception of the universe, it is ruled out by Occam's razor. On the other hand, if an absolute frame of reference existed it would have certain measurable consequences. Those consequences not being observed, we must conclude that there is no such absolute frame.

<i>That's also a problem with relativity, and I will say this again and again, it can only be tested in one way.</i>

And you will continue to be wrong again and again. The Earth moves around the sun, changing direction all the time. Yet if we do the same experiment at intervals of six months we get the same result, even though the Earth is moving in the opposite direction. That fact alone shows that all inertial reference frames are equivalent. There is no aether to provide an absolute standard of rest. The change in reference frame also tests relativity "both ways".

Also, all relativistic explanations work from both reference frames involved. The Twin paradox can be equally analysed either from the Earth frame or the traveller's frame. The decay time of muons can be measured either from the Earth frame or from the muon's frame and the results are consistent with what is observed - that muons can reach the ground from the upper atmosphere despite the fact that they should decay before they reach the ground if relativity was wrong.

<i>Further, imagine you fly away with that ball with all the equipment that you can imagine. what will you be able to do in order to see if it is really you who is moving?</i>

Nothing. That's the point of relativity. There is no "who is really moving". That implies an absolute frame of reference.

<i>IT MEANS THAT WITH THE PRINCIPLE NO FALSIFICATION IS EVEN POSSIBLE </i>

Falsification of relaitivity could take place in any number of ways. If the predicted advance in the perihelion of Mercury did not match the observations, or the lifetimes of muons did not match predictions, or we observed massive objects travelling faster than the speed of light, or binary pulsars did not lose energy due to gravitational radiation, then relativity would be falsified.

<i>When I push against a wall and I push so hard that I get through it with my arms, then the bricks are falling out on the ground on the other side. It is not the earth and me who are falling up.</i>

From the point of view of the bricks pushed out of the wall it is.

<i>If the earth is flying away 150 metres from the baseball, everyone should feel this.</i>

Do you feel yourself to be rotating at 1000 km/hr? No? Well, relative to the Earth's centre you are. Same reason for the baseball example.

<i>I also tell you, there's some pink elephants walking around here in my room. the problem is that you can only see them if you are here in my room....</i>

Can I do quantitative measurements to show that your pink elephants exist or do not exist? I can to show that relativity exists.

<i>...every single test [of relativity] also confirms that these effects can be due to kinetic energy or grav. energy.</i>

You are wrong on that point.

<i>Simply --> Lorentz equations remain, intepretation lil different and the mechanism behind the changes is explained (you can look up the papers of Marmet, it agrees fully with what we see, the only thing that is different is the mechanism behind it)</i>

Marmet's physics has flaws in it. It cannot replace relativity, since it does not match the observations we make. It is no substitute.

<i>I guess you've flied on an electron at 99,999 % of c and that whilst going so fast, you've actually been able to see that my clock down there was going slower.</i>

No. But I've "flied" (metaphorically speaking) on an aircraft with an atomic clock in it which observed that effect. That experiment was peer reviewed and published.

<i>Moreover, you've not accelerated at all. Yep, that's right. You went all the way up to 99,9 % of c without acceleration.</i>

Nobody ever said you can get to 99.9% of the speed of light without accelerating. I don't know where you get that idea from.

<i>Indeed, relativists regard you as an inertial frame.</i>

An accelerated frame is, by definition, non-inertial. I suggest you find out what is meant by that term.

<i>First of all, you'll get the effect like looking at the wooden beams connecting the railways --> when the train goes fast, you'll be able to see each individual, but when it goes 80 km/hour you'll see all of them like one piece</i>

That's a problem with the processing rate of your eye, nothing more.

<i>If you go even more faster on that e-, you practically see nothing: just colours and shapes, maybe not even shapes
if you're not dead already, you'll realise that you're going fucking fast</i>

How will I know I'm going f**ing fast? How will I know that it's not everything moving past me f**ing fast? Oh, sorry, I asked that before and you couldn't answer.

James R, I see that your brain lacks insight on the point of falsification. You just don't get it (now I know you'll tell me that I don't understand relativity ....).(and the measurements are not in both ways) I'll reply later if I feel like it, it's fucking good weather overhere now :p

<FONT COLOR=red>Can you give me a test which will tell me whether it is really the baseball or the Earth which is moving? If not, then either point of view is equally good. </FONT>


JR, could the CBMR be used to do this?

Or how about lining the edge of the ball up with the edge of the moon and the horizon of the Earth with the edge of the moon?

"""No. The correct conclusion to draw is that the universe might be an illusion."""

So let me put it also like that: *Maybe* it is like that from the ball's FOR.

"""On the other hand, if an absolute frame of reference existed it would have certain measurable consequences."""

why do you keep talking about an absolute frame of ref.? we are not discussing that
It is not because we reject the rel. pr. that we have to adopt an abs. F.O.

"""The Earth moves around the sun, changing direction all the time. Yet if we do the same experiment at intervals of six months we get the same result, even though the Earth is moving in the opposite direction."""

I have no idea what you are saying here. The earth never moves in the opposite direction.

"""That fact alone shows that all inertial reference frames are equivalent. There is no aether to provide an absolute standard of rest. The change in reference frame also tests relativity "both ways"."""

stop going towards the aether
we are talking about FOR's in the view of rel.
the change in FOR is always pure maths
basically, you just tell the exact SAME story but you change the FOR in your sentences
one way

"""Also, all relativistic explanations work from both reference frames involved. The Twin paradox can be equally analysed either from the Earth frame or the traveller's frame."""""

wooooooooooooooooow, amazing evidence here- ---> a gedanken experiment

"""The decay time of muons can be measured either from the Earth frame or from the muon's frame and the results are consistent with what is observed"""

You haven't flown together with a muon and shown that our time on earth went slower from that FOR

"""that muons can reach the ground from the upper atmosphere despite the fact that they should decay before they reach the ground if relativity was wrong."""

one way one way one way one way

it has to do with grav. energy

I said: Further, imagine you fly away with that ball with all the equipment that you can imagine. what will you be able to do in order to see if it is really you who is moving?

"""Nothing. That's the point of relativity. There is no "who is really moving". That implies an absolute frame of reference."""

I didn't have to type anything again, it already stands here::

IT MEANS THAT WITH THE PRINCIPLE NO FALSIFICATION IS EVEN POSSIBLE

"""That implies an absolute frame of reference"""

I don't think so. You just have to see every scenario apart. You have huge systems in the universe who have particular directions and starting from that view, if you'd have enough information on all of them, you can work your way out in finding out who is moving towards where, yes, relative to those systems
and who is really moving from all those systems? they are all moving, each one of them

You cannot see the Pink elephants because the principle implies that, yet you are told that they MUST be there. You can't show in an experiment who is moving yet all experiments support the principle .... what a flawed logic.

"""Falsification of relaitivity could take place in any number of ways. If the predicted advance in the perihelion of Mercury did not match the observations, or the lifetimes of muons did not match predictions, or we observed massive objects travelling faster than the speed of light, or binary pulsars did not lose energy due to gravitational radiation, then relativity would be falsified.""""

--> Lorentz equations are used by relativity
we can use these equations for different interpretations

""or we observed massive objects travelling faster than the speed of light""

according to the big bang th. this is happening (oeps, it is space itself that is doing that so no motion involved, yeah right)

"""From the point of view of the bricks pushed out of the wall it is."""

doesn't make sense any sense, it is not guts here, it is logic that is in danger

that's the trick: for the brick, the earth and us are falling up
then a logic person says: hey, that's not possible, we should feel that
smart einstein devotee: ONLY from the FOR from the brick this is happening so from Our FOR you cannot feel this

waw, I am impressed by this kind of nonsense.

""do you feel yourself to be rotating at 1000 km/hr?"""

-> is constant, if the rot. would accelerate you'd fall of your chair

"""Can I do quantitative measurements to show that your pink elephants exist or do not exist? I can to show that relativity exists. """

one way one way one way + Lorentz equations are correct

"""You are wrong on that point. """

I'm impressed by this answer.

"""Marmet's physics has flaws in it."""

Yes, you told me that before. Let me see, what was the argument again in that other thread, oh yes: it is not in accordance with the principle of rel.
Again, I'm impressed by that.

"""since it does not match the observations we make."""

yes it does
equally, mercurius' orbit is easily explained

"""No. But I've "flied" (metaphorically speaking) on an aircraft with an atomic clock in it which observed that effect. That experiment was peer reviewed and published."""

Have they observed that the clocks on earth went slower for the pilots?

"""Nobody ever said you can get to 99.9% of the speed of light without accelerating. I don't know where you get that idea from."""

well, I've been told SR only accounts for inertial frames which means NO acceleration

I said: First of all, you'll get the effect like looking at the wooden beams connecting the railways --> when the train goes fast, you'll be able to see each individual, but when it goes 80 km/hour you'll see all of them like one piece

""That's a problem with the processing rate of your eye, nothing more.""

well my friend, isn't that what an observer does? observing and describing what he sees

I said: If you go even more faster on that e-, you practically see nothing: just colours and shapes, maybe not even shapes
if you're not dead already, you'll realise that you're going fucking fast

"""How will I know I'm going f**ing fast? How will I know that it's not everything moving past me f**ing fast? Oh, sorry, I asked that before and you couldn't answer."""

Yes I can answer.
----------------------------------------------------------------------------
first, just this thought:
----------------------------------------------------------------------------
Our solar system + its galaxy is moving in a particular direction, they all have the same momentum.
let us say they move towards direction A.
Now, I come at 99,9% speed of c from direction B (which is the opposite direction) and I fly by the earth towards direction A as well.

SR says that from the FOR of me, it is me who is stationary and it is the earth and its galaxy who are flying at 99,9% of c towards direction B. Now, dir. A is towards expansion and B is the opposite. If we believe the BB, this expansion is a fact and it has a certain direction. Now I have to believe that we are expanding and moving back at the same time.
We interpret the redshift as being Doppler. We see that almost all stars have red shifts. They are all flying away from us. We say that from any star the same thing is seen: red shifts. We say, everyone is flying away from each other seen from any FOR. How can we then believe that because little Me flies by that this whole galaxy must be moving in the opposite direction. It can't be moving in both directions. An observer on another star will tell us that we still have a redshift and that the guy flying by has a blue shift.

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

Now, how will you know that it is really you who is moving?

When you go to 99,9% of c you will be accelerating all the time. You will feel that you are moving. Even if everything would turn black, you'd still feel it.

If a train is riding 100 km/h at constant speed, would you say that from the FOR of the earth (or stationary person) that it is the earth rotating faster at that exact spot??

I will tell it one more time very clearly what I think:
----------------------------------------------------------------

The principle of relativity IMPLIES itself, that we CANNOT know or test in ANY WAY if it is CORRECT in it's OWN assumption that WE cannot know WHO IS REALLY MOVING.

Do you understand this? No Falsification is thinkable. None. Nada.
All the proof for SR is NOT proof for its principle, it's always one way and it is proof that the Lorentz equations are correct but not proof for the INTERPREATION of the eqautions.

Hi c'est moi,

"I have no idea what you are saying here. The earth never moves in the opposite direction. "

I hope we both agree that the earth orbits the sun. In order to "orbit" the velocity vector has to change constantly to maintain the circular/elliptic orbit. In six months from now, the earth's velocity vector will be pointing in the opposite direction it is going now.

"stop going towards the aether. we are talking about FOR's in the view of rel. the change in FOR is always pure maths"

I think you underestimate the importance of frames of reference (FOR). Im my opinion, the relation between different FOR's is the heart of all physics. If we both observe the same experiment, then there must be some way to link the results we both get. Even in our everyday experience, different observers get different results. I'll use the classical train example here. If you drop a penny inside the train, an observer standing in the train will say it fell straight down, and someone observing that experiment next to the railroad will say it fell in a curved way. Since we're both talking about the very same penny dropping - and very important - and that we both assume that the laws of physics are the same for everyone, then there must be some way to relate the results.

First of all, if you assume the laws of physics to be different for two observers, then you can stop reading here. If everybody has his own sets of rules and laws, then there is no possible way that we can ever agree on the results of an experiment (you will firmly believe your measurement because you saw it happen with your own eyes, I will firmly believe what I saw). This is exactly the (Galilei) principle of relativity, and I quote it here for reference:

Galilei principle of relativity:
For an isolated system:
1. One can always find a coordinate system to describe events, this is called an inertial system.
2. Every other coordinate system that moves with a constant velocity with respect to an inertial system, is again an inertial system.
3. The laws of physics are the same for every inertial system.

I can't see why someone would disagree with the first two aspects, in the first point we assume that we can use numbers to label events (which we can call x,y,z,t for example). This is a necessity to link mathematics and the real world. The second point is the definition of an inertial system, and well, a definition is a definition, there is no right or wrong there (perhaps a "useful" or "worthless", but you can never disagree on a formal definition).

Disagreeing with the Galilei principle of relativity is disagreeing with the fundamental building blocks of science: if you cannot use mathematics to describe nature (first point) or if you don't believe there are other FORs (point two), or if you refuse to assume that the laws of physics are the same for everyone, well then there is no point in continuing science. (irony mode on) I guess we better all pack our bags and go watch Jeopardy (irony mode off) :).

Now, for what you said: aether is a very important concept in the idea of FORs, but you have to realise that nowadays the word aether is no longer used as some "medium in which EM waves propagate" but is used as a synonym for "an absolute FOR". You say that disagreeing with the principle of relativity does not necesserily imply the existance of an absolute FOR.

Two remarks: first of all (and I admit this is a stupid remark), if you don't accept the principle of relativity, then there's no such thing as a FOR. But what you probably refer to is, and I quote from your previous post:

It seems that all of you assume that once you take the FOR of something, that that's the one who should be regarded stationary and the other one moving. That's absurd. In fact, both are moving. The earth around the sun and the ball away from the earth.

That assumes the existance of an absolute frame of reference (or aether as James R called it). When you say that something is moving, you always have to specify what it is moving relative to. There are two options in your reasoning:

Either you are floating in your spaceship around the earth and you say "hey look, the earth is moving away, and so is that ball James R has thrown up". But then you are talking from your own point of view, your own FOR. But since all FORs are moving, so are you and hence the quest for something that you are moving relative to is started again. You can repeat this argument a couple of times, you'll always end up with the same conclusion: I can see all the other FORs moving, but since I am also moving, what am I moving relative to ?
Or you assume that there is some kind of absolute, non-moving "something" that always, under all circumstances stands still. This "something" is called the aether. Since the aether is always standing still, all other FORs move relative to the aether.

This is how aether necesserily comes into the discussion.

You say that both are moving, well you are correct if you assume an absolute frame of reference. However, from our point of view, the earth is stationary: we walk on it, and for some magical reason (no magic involved ofcourse) it doesn't move away from our feet. That's because in our daily lives we talk about the FOR of the earth, and the earth is stationary in that FOR. From the point of view of the sun, the earth is ofcourse moving, but then the sun is stationary. An observer on the sun will not see the sun moving away, because by definition, the FOR of the sun is attached to the sun and moves along with it as it circles around the centre of our galaxy.

In the rest of your post, you argue that one cannot predict a result in another FOR if you perform the experiment in your own FOR. Well, because of the principle of relativity (which I hope to have "proven" to be essential for physics above), you can: the laws of physics are the same for everybody, and hence if a penny falls downward here in Belgium, it won't float upward in China if I perform the experiment there.

This example might look silly compared to particles moving at 0,99999999c, but the idea is the same. If you transform an experimental result from one FOR to another, using the idea that the laws of physics are the same for both, then you are forced to conclude all the counterintuitive things that have been mentioned about particles at 0,99999999c.

Well, I can see this one coming from a mile away: you are going to question the mathematical formulas used to transform from one FOR to another. Unfortunately, these transformation rules are deduced immediatelly from the principle of relativity. Because we are going to talk about Lorentz transformations, I should first add that the Galilei principle of relativity I mentioned above is not the principle of relativity used in the Theory of Special Relativity. What Einstein did was simply extend the Galilei principle of relativity:

Einstein principle of relativity:
For an isolated system:
1. One can always find a coordinate system to describe events, this is called an inertial system.
2. Every other coordinate system that moves with a constant velocity with respect to an inertial system, is again an inertial system.
3. The laws of physics are the same for every inertial system.
4. The speed of light is the same in all inertial frames.

Well, the Lorentz transformations are immediatelly deduced from these simple four points. As I mentioned before, I cannot imagine how you would disagree with the Galilei principle of relativity (points 1 to 3), so if you disagree with the Lorentztransformation, then it must be point 4 in the Einstein principle of relativity you don't believe. I'm not going to repeat what has been said quite some times before on this forum, but the absoluteness of the speed of light is an assumption that is backed up by experiments.

Finally you concluded:

"The principle of relativity IMPLIES itself, that we CANNOT know or test in ANY WAY if it is CORRECT in it's OWN assumption that WE cannot know WHO IS REALLY MOVING.

Do you understand this? No Falsification is thinkable. None. Nada.
All the proof for SR is NOT proof for its principle, it's always one way and it is proof that the Lorentz equations are correct but not proof for the INTERPRETATION of the equations."

First of all, the principles that construct a theory can never falsify the theory itself. External theories are required to do that, which is why no falsification is possible from the point of SR. You say that we cannot tell who is really moving, yes that is true and is one of the basic reasons why most scientists don't believe in an absolute frame of reference, or aether. I think I've addressed the absolute/relative FOR issue in enough detail above :).

Quite a long post, I hope I've succeeded in explaining the principle of relativity in enough detail. The principle of relativity is a postulate, and I hope that you'll agree that it is not as unreasonable as you might have thought at first.

Bye!

Crisp

I still don't agree with you, but let me get back to this tomorrow. You seemed to have missed out the thought I had about those huge systems who are all moving away from each other and which COULD be used in SOME SENSE as a *standard* frame of reference.

c'est moi:

Crisp has explained things rather well, so I'll try not to repeat too much of what he said.

<i>The earth never moves in the opposite direction.</i>

Draw a circle on a piece of paper. Imagine your pen tip is the Earth and the centre of the circle is the sun. When you start drawing, let's say your pen moves to the right. Then, when you have drawn half the circle your pen will be moving to the left.

<i>the change in FOR is always pure maths</i>

No. It has nothing to do with maths unless we want to get quantitative about things. The term "frame of reference" is nothing more than a fancy way of saying "point of view". A different FOR is simply a different point of view.

If you're sitting in a car moving at 60 km/hr in a straight line, you have a different point of view than somebody sitting by the roadside watching you drive past - agreed? All relativity says is that you can't do any experiment inside the car which will tell you whether it is you or the person outside who is "really" moving. That is the crux of the matter, which you do not seem to understand. If you disagree, all you have to do is to come up with ANY test which can tell me unequivocally who is moving and who isn't. If such a test was possible, surely you'd be able to explain it to me? I am telling you that no such test is possible. And Einstein agrees with me. You can dodge the issue as much as you want by introducing irrelevancies, but the question keeps coming back to the same thing. Can you give a test or can't you? I say you can't.

I said: <i>Also, all relativistic explanations work from both reference frames involved. The Twin paradox can be equally analysed either from the Earth frame or the traveller's frame.</i>

You replied: <i>wooooooooooooooooow, amazing evidence here- ---> a gedanken experiment</i>

Except that it has been done with atomic clocks, which are rather real.

<i>You just have to see every scenario apart. You have huge systems in the universe ...</i>

Forget star systems and so on. If you can't come up with a test in my car example, you won't be able to come up with one for star systems either.

<i>Lorentz equations are used by relativity
we can use these equations for different interpretations</i>

Yes. So?

<i>that's the trick: for the brick, the earth and us are falling up
then a logic person says: hey, that's not possible, we should feel that
smart einstein devotee: ONLY from the FOR from the brick this is happening so from Our FOR you cannot feel this</i>

The question of whether you should feel motion is a completely separate one from the FOR question. Let's not get into that now. Let's sort out your more basic misunderstandings first, since the resolution of the perceived feeling problems you think are there are a bit more complicated.

I said: <i>Marmet's physics has flaws in it.</i>

You replied: <i>Yes, you told me that before. Let me see, what was the argument again in that other thread, oh yes: it is not in accordance with the principle of rel.</i>

Just because you did not understand my argument doesn't mean it was wrong. Maybe when we sort out your basic lack of understanding you will be able to understand what I wrote. At this stage it is enough to simply say that what you've said here that I argued isn't what I argued. Such an argument would be begging the question - a fallacy I am careful to avoid.

<i>Have they observed that the clocks on earth went slower for the pilots?</i>

Yes.

<i>well, I've been told SR only accounts for inertial frames which means NO acceleration</i>

That's not quite true. It is most easily applied in the case of no acceleration, but you can solve the equations numerically where there is acceleration. Things just become a lot more complicated.

<i>When you go to 99,9% of c you will be accelerating all the time. You will feel that you are moving.</i>

Yes, I agree with that totally. But if you're travelling at a constant speed of 0.999c, you won't feel anything. You'll feel exactly the same as sitting in a car travelling at 60 km/hr, or sitting at home in your easy chair. And that's the point of relativity.

<i>The principle of relativity IMPLIES itself, that we CANNOT know or test in ANY WAY if it is CORRECT in it's OWN assumption that WE cannot know WHO IS REALLY MOVING.</i>

That is wrong. We can easily test it. All we need to do is to do ANY experiment in both a "stationary" reference frame and another one moving at constant velocity relative to it (like the car and the bystander on the road), and get different results WHICH ALLOW US TO TELL WHO IS "REALLY" MOVING. So, we're back to the original question - can you come up with one?

These are busy weeks, too busy actually, I'll answer shortly, Sorry for that, I will take the time to answer your (long) replies better :)


""Draw a circle on a piece of paper. Imagine your pen tip is the Earth and the centre of the circle is the sun. When you start drawing, let's say your pen moves to the right. Then, when you have drawn half the circle your pen will be moving to the left.""

for me the earth always moves clockwise (or is it anti-clockwise?), I guess you understood what I meant

"""all you have to do is to come up with ANY test which can tell me unequivocally who is moving and who isn't. If such a test was possible, surely you'd be able to explain it to me?"""

I'll explain you my friend :) This is the story of the arrogant observer who thought he knew it all. His eyes were as a gun to him :p

This is my new thought on this:

object A has coördinates x1,y1 and z1
object b has coördinates x2, y2 and z2

Everything is dark. Only object A and B can be seen. They are both approaching to each other. You are observing this.

Relativity says that you cannot know which one of the two is moving because you have nothing to REFER to. But that's not where relativity stops. If it would stop there, it would be fine for me. It then goes on to conclude that the motion shoud depend on which FOR you take. This is someting I cannot agree with.

Well let me tell you, it is entirely because the observer is limited in doing science. IMAGINE that we'd know that the coördinates of A remain x1,y1 and z1 and that object B's coördinates are changing from x2, y2 and z2 to x1/2, y1/2 and z1/2 to etc. etc.

How can we test this? We cannot. Fact is, in this gedankenexperiment, the coördinates are there and somehow we know that A's coördinates remain unchanged, conclusion: B is moving and A isn't.

Imagine we are all gifted and we'd be able to see the structure of the space surrounding us. We'd see it like they see it in mathematics. A sea of points. Every object has its coördinates. Problem is, we are not that gifted. Space is an ABSOLUTE FOR but unfortenately, we cannot use it. This is not proof in favour of relativity. This is a conclusion that we draw.

""I am telling you that no such test is possible. And Einstein agrees with me.""

Hey I agree also. But you can't use this in favour of relativity. You should check the path of logic you are following here. The physics community has been mistaken in doing this.

""IHave they observed that the clocks on earth went slower for the pilots?

Yes. """

I would like to have some links that give me a rapport of this experiment and where i can read how that hapenned.
Simply saying yes does not do the job.

"""That's not quite true. It is most easily applied in the case of no acceleration, but you can solve the equations numerically where there is acceleration. Things just become a lot more complicated."""

--> thed said this

"""That is wrong. We can easily test it. All we need to do is to do ANY experiment in both a "stationary" reference frame and another one moving at constant velocity relative to it (like the car and the bystander on the road), and get different results WHICH ALLOW US TO TELL WHO IS "REALLY" MOVING."""

No you can't test it. The principle is not a physical principle and therefore it cannot be tested. Motion remains an objective thing which happens in the space-dimension (with time as an additive variable). Motion cannot change because an observer is at an other coördinate in space. The penny that was dropped on the train falls straight with the observer on the train because the observer is moving with the penny and hence his observation is an illusion caused by his own motion. There's nothing special about it. The penny's motion seen from the point of view of the Space dimension is always the same. No test can be performed to use it but that is no argument. The scientist as an observer should understand this. Do you understand this?

"""So, we're back to the original question - can you come up with one?"""

I don't have to. You are missing the point.

Gotta run now. Hope not too many typos
:D

Hi c'est moi

"Everything is dark. Only object A and B can be seen. They are both approaching to each other. You are observing this.
Relativity says that you cannot know which one of the two is moving because you have nothing to REFER to."

Wrong. For the outside observer, both are moving. From the point of view of object A, B is moving. From the point of view of object B, A is moving.

"But that's not where relativity stops. If it would stop there, it would be fine for me. It then goes on to conclude that the motion shoud depend on which FOR you take. This is someting I cannot agree with. "

Well, then you don't agree with anything you see in your every day life.

Have you ever sat in a car that was cruising along the highway ? From that perspective, you see the trees alongside the road moving, and the car does not move for you. The reasoning you make is the following: it is because you KNOW that trees don't move by themself that you can deduce that the car is the object moving. Hence the prefered frame of reference is the car.

The problem is that this is only half the story. If I would put the trees on small wheels and move them backwards, then you would have the same impression, even though it is not the car moving in that scenario.

I'm sure you ever experienced the following situation: you are sitting in a train that is standing still in a railway station, and suddenly the train standing still next to you starts to move. The first thing that pops into you mind is "hey, we've started moving again" until you realize you don't feel the normal acceleration you experience when trains depart (this gives this strange feeling in your stomache ;)).

The point is: motion is very dependent of the frame of reference.

Bye!

Crisp

c'est moi:

It is really a very simple concept. A frame of reference is a <b>point of view</b>, nothing more. Do you agree that people have different points of view?

The only thing relativity does is to allow us to predict observations from a different point of view to the one we're in. If I watch you drive past me in your car, relativity allows me to predict how things will look to you, even though I am not in the car.

Let's look at your example:

<i>object A has coördinates x1,y1 and z1
object b has coördinates x2, y2 and z2

Everything is dark. Only object A and B can be seen. They are both approaching to each other. You are observing this.</i>

You've missed the crucial point: <b>where am I in this picture?</b>. That's what matters - where the <b>observer</b> is, not where anything else is. Whose <b>point of view</b> are we looking at objects A and B from? Somebody sitting on object A? Somebody travelling past object B at half the speed of light? Because our choice of observation point (FOR) affects what we see. It's common sense. It's everyday experience. I can't see how you can possibly question this.

<i>Relativity says that you cannot know which one of the two is moving because you have nothing to REFER to.</i>

That's because you <b>haven't told me where I am</b>!

<i>It then goes on to conclude that the motion shoud depend on which FOR you take. This is someting I cannot agree with.</i>

You experience that every day of your life. Whenever you go for a walk you see the ground moving past under your feet. Wake up and look at the world around you! Change your point of view and the world looks different.

<i>...the coördinates are there and somehow we know that A's coördinates remain unchanged, conclusion: B is moving and A isn't.</i>

You're <b>assuming</b> a particular co-ordinate system here and you don't even realise it. You're assuming a co-ordinate system fixed in some space separate from A and B. But in fact, there are MANY different co-ordinate systems we could choose. We can choose a co-ordinate system which always has A at (0,0), or system which has (0,0) at the centre of mass of the A-B system. Or something else. We don't know whether the <b>co-ordinates</b> of A and/or B change until we specify which co-ordinates we are using.

<i>Space is an ABSOLUTE FOR but unfortenately, we cannot use it.</i>

Wrong. That's what I keep telling you, but you don't understand. Once again: <b>THERE IS NO ABSOLUTE FOR</b>. If there was one, you'd be able to do an experiment to show whether an object is "really" moving. And you yourself admit that no such experiment is possible. Therefore, logic compels you to accept my statement.

<i>I would like to have some links that give me a rapport of this experiment and where i can read how that hapenned.</i>

I don't have time to search the web right now to find the relevant paper. I'm sure you can find it as well as I could, if you're really interested.

<i>The penny that was dropped on the train falls straight with the observer on the train because the observer is moving with the penny and hence his observation is an illusion caused by his own motion.</i>

No. In that observer's FOR, the penny <b>really</b> drops straight down. That's no illusion. It's real. He can bend down and pick it up.

i appolagize if this issue has already been resolved, but i am tired of spending all day in this forum, so here it goes. as to the baseball example, the FOR should be yourself, but imagine that you become the point inbetween the earth and the ball. the ball magicly leaves the earth, and you see the ball traveling quickly, and the earth traveling slowly(because it is much more massive than the ball) and you remain in the center of gravity between the two :)

James R,

There is such a thing as an absolute frame of reference.

The relative velocity of an object is equal to the difference between that objects absolute velocity, and the absolute velocity of the object you are comparing it to.

In other words, the relative frame of reference of object A compared to object B, is derived from the absolute physical values of object A and B. If an absolute frame of reference didn't exist, neither would any relative frames of reference.

Just because there isn't yet a way to measure the absolute frame of reference of an object, doesn't mean that an absolute frame of reference doesn't exist.

Tom

Yes, Tom. And just because there's no way to verify that there's a pink dragon called Herbert living in my garage doesn't mean he doesn't exist.

James R.

The unrelativistic properties of light in any frame of reference is proof that there is an absolute frame of reference.

Tom

"""I'll use the classical train example here. If you drop a penny inside the train, an observer standing in the train will say it fell straight down, and someone observing that experiment next to the railroad will say it fell in a curved way. Since we're both talking about the very same penny dropping - and very important - and that we both assume that the laws of physics are the same for everyone, then there must be some way to relate the results."""

we must not forget about illusionary visions

"""First of all, if you assume the laws of physics to be different for two observers, then you can stop reading here. If everybody has his own sets of rules and laws, then there is no possible way that we can ever agree on the results of an experiment (you will firmly believe your measurement because you saw it happen with your own eyes, I will firmly believe what I saw).""""

I never questioned this. Indeed, all laws are the same for anyone, when I see motion and you don't, then one of us is wrong. Simple.

"""This is exactly the (Galilei) principle of relativity, and I quote it here for reference:

"""The second point is the definition of an inertial system, and well, a definition is a definition, there is no right or wrong there (perhaps a "useful" or "worthless", but you can never disagree on a formal definition)."""

I read the quote of Galileo about the boat and I still don't agree with it.

"""Disagreeing with the Galilei principle of relativity is disagreeing with the fundamental building blocks of science: if you cannot use mathematics to describe nature (first point) or if you don't believe there are other FORs (point two), or if you refuse to assume that the laws of physics are the same for everyone, well then there is no point in continuing science."""

1. Maths are an abstractation of reality yet usefull, we need to be carefull with the interpretation of numbers. With maths alone, anything can be prooven. We also need to understand that maths is only an translation of what we think is happening.

2. Points of view or FOR's are a fact. But don't we all agree in life that certain people are wrong in their point of view? A guy who's nuts and who's seeing all kinds of non-existing creatures on the street, is surely telling his point of view of his reality. Who are we to laugh with him? Can we be 100% sure that what he sees is not true? Yet, normal people will tell him that we he sees is wrong and what they see is reality.

I strongly believe that switching between FOR's is more about illusionary effects than reality. The train-scenario is an illusionary effect and is basically an example where information is the key. If we would be supersensitive beings and feel every detail of the topography below us in a train, we'd perfectly be able to tell if out train is really moving or if it is an illusionary effect. If we'd be unlimitely sensite we'be able to feel space and use that as absolute FOR. Unfortenately we can't.

"""That assumes the existance of an absolute frame of reference (or aether as James R called it). When you say that something is moving, you always have to specify what it is moving relative to.""""

I would like to hear a defenition of "motion" which is the key-word of this debate in light of the rel. principle.

I strongly believe that motion is like mass. It's independent. Likewise, the motion of light is independent and absolute which proves motion can be this.

"""You can repeat this argument a couple of times, you'll always end up with the same conclusion: I can see all the other FORs moving, but since I am also moving, what am I moving relative to ?"""

to space

Motion is defined as moving through space.

"""However, from our point of view, the earth is stationary: we walk on it, and for some magical reason (no magic involved ofcourse) it doesn't move away from our feet."""

that's because it's speed is rather constant

"""That's because in our daily lives we talk about the FOR of the earth, and the earth is stationary in that FOR."""

that's our big illusion
our view is so to speak "defect", because we ourselves are always moving with it

the only objective observer is one who is not in motion himself

"""Well, I can see this one coming from a mile away: you are going to question the mathematical formulas used to transform from one FOR to another. Unfortunately, these transformation rules are deduced immediatelly from the principle of relativity."""

they were originally used within an absolute frame of reference

"""Well, the Lorentz transformations are immediatelly deduced from these simple four points."""

you are going in the wrong direction here if I know my history well enough

first came along the equations, then Einstein

'The principle of relativity IMPLIES itself, that we CANNOT know or test in ANY WAY if it is CORRECT in it's OWN assumption that WE cannot know WHO IS REALLY MOVING.'

"""First of all, the principles that construct a theory can never falsify the theory itself. External theories are required to do that, which is why no falsification is possible from the point of SR."""

this is very much wrong
imagine I invent the evolution theory right now
we find all the fossils in logical order
then comes a day where we find complex human beings in layers where they shouldn't be as predicted by my theory
and more days come like that
well, this is falsification of the principle of evolution from within the theory itself

"""You say that we cannot tell who is really moving, yes that is true and is one of the basic reasons why most scientists don't believe in an absolute frame of reference, or aether. I think I've addressed the absolute/relative FOR issue in enough detail above ."""

I think you haven't understood or interpretted correctly my quote which I have left between '... ' .

"""The principle of relativity is a postulate, and I hope that you'll agree that it is not as unreasonable as you might have thought at first."""

it is
:cool:

"""Have you ever sat in a car that was cruising along the highway ? From that perspective, you see the trees alongside the road moving"""

no, i pass by them
I'm not a cow so I understand this

""and the car does not move for you. The reasoning you make is the following: it is because you KNOW that trees don't move by themself that you can deduce that the car is the object moving. Hence the prefered frame of reference is the car."""

wrong. Hence, information is the tool of the observer.

"""The problem is that this is only half the story. If I would put the trees on small wheels and move them backwards, then you would have the same impression, even though it is not the car moving in that scenario."""

right --> impression, not reality

"""The point is: motion is very dependent of the frame of reference. """

the point is that the observer is quite pathetic and not so much of a good observer

"""Do you agree that people have different points of view? """

yes, but some of them seem to be wrong as well ;)

"""You've missed the crucial point: where am I in this picture?."""

I thought you'd understand that the observer is watching this happening and is not on one of the objects.

so again, Relativity says that you cannot know which one of the two is moving because you have nothing to REFER to.

"""Change your point of view and the world looks different."""

take some LSD or XTC it changes even more beautifully

"""You're assuming a particular co-ordinate system here and you don't even realise it."""

space itself is quite a mystery ... what is it really? it's about dimensions and we've got some mathematical definitions for it but it's actually a curious thing
space for me is absolute
anything has unseen coördinates in space which are independend of anything

"""But in fact, there are MANY different co-ordinate systems we could choose."""

we don't choose

"""Wrong. That's what I keep telling you, but you don't understand. Once again: THERE IS NO ABSOLUTE FOR. If there was one, you'd be able to do an experiment to show whether an object is "really" moving."""

That's what I call wrong logic. I told, there is probably no such experiment because we are limited. Limitation don't mean that a principle is prooved.

"""And you yourself admit that no such experiment is possible. Therefore, logic compels you to accept my statement."""

look up "logic" in a dictionarry

"""I don't have time to search the web right now to find the relevant paper. I'm sure you can find it as well as I could, if you're really interested."""

I'm not really interested. If you say something you have to say why.

"""No. In that observer's FOR, the penny really drops straight down. That's no illusion. It's real. He can bend down and pick it up."""

yes, and whilst he is bending down, he is still moving with it
it's still an illusionary effect of his own motion

C'est Moi and James R,

If light always follows an absolute frame of reference, couldn't the absolute speed and direction of an object be measured using lasers??

Example: The absolute motion of an object would be the difference between the direction and speed of a beam of light(which is absolute) and the relative frame of reference of the object.

I believe a device could be built, using three lasers and a gyroscope, which would be able to measure the absolute motion of an object.

Tom

James R, I looked it up and as I initially thought your are wrong.

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/airtim.html#c3

Prosoothus, this idea seems interesting :)

c'est moi:

You're very good at asserting that I am wrong, but you seem incapable of providing any evidence of that other than your gut feeling. Much as I might respect your guts, I find that I have to side with Einstein, Galileo, Newton, and practically every practising physicist on this question.

I asked: <i>Do you agree that people have different points of view?</i>
You said: <i>yes, but some of them seem to be wrong as well </i>

Then you'll be able to provide a test by which I can tell who is right and who is wrong in any situation, won't you? So, I drop a penny in a train and see it fall to the floor. You say that's wrong. What test can I do <b>inside the train</b> to show that the penny doesn't really drop straight to the floor?

I said: <i>You've missed the crucial point: where am I in this picture?</i>
You said: <i>I thought you'd understand that the observer is watching this happening and is not on one of the objects.</i>

Please understand. I'm sick of repeating myself. I am asking you: <b>Where is the observer watching from?</b> The answer to that question is crucial, yet you seem continually to overlook it. You say "the observer is watching this happening"? From where? From the planet Mars? From inside a spaceship flying past at half the speed of light? From sitting on object A? Where?

<i>space for me is absolute anything has unseen coördinates in space which are independend of anything</i>

Oh? Perhaps you'd like to support that statement with something other than gut feeling, because I've given you lots of reasons why that is not the case, yet so far you've given me no reason why it is the case.

I said: <i>But in fact, there are MANY different co-ordinate systems we could choose.</i>

You replied, rather cryptically: <i>we don't choose</i>

What????!!

<i>I looked [the clock experiment] up and as I initially thought your are wrong.</i>

Wrong about what? Wrong in what way? I don't think so.



Prosoothus:

<i>If light always follows an absolute frame of reference, couldn't the absolute speed and direction of an object be measured using lasers??</i>

There's no such thing as an absolute frame of reference.

<i>I believe a device could be built, using three lasers and a gyroscope, which would be able to measure the absolute motion of an object.</i>

Tell me how.

Originally posted by Prosoothus
C'est Moi and James R,

If light always follows an absolute frame of reference, couldn't the absolute speed and direction of an object be measured using lasers??


1) The measuring device would have to take into account all the changes in material and gravity and all between point A and point B, to make sure speed calculations are correct.

2) Point A and point B are still in relative motion.

"""You're very good at asserting that I am wrong, but you seem incapable of providing any evidence of that other than your gut feeling."""

the evidence is all about the limitations of the observer
limitations cannot become principles

"""Much as I might respect your guts, I find that I have to side with Einstein, Galileo, Newton, and practically every practising physicist on this question."""

everyone is free to think and to believe what he wants but it's interesting to discuss these thoughts and believes

"""I asked: Do you agree that people have different points of view?
You said: yes, but some of them seem to be wrong as well

Then you'll be able to provide a test by which I can tell who is right and who is wrong in any situation, won't you? So, I drop a penny in a train and see it fall to the floor. You say that's wrong. What test can I do inside the train to show that the penny doesn't really drop straight to the floor?"""

you, the penny and the floor are moving together as one system
the penny doesn't REALLY follow a straight path nor a curved path
I have no idea what the REAL motion is of the penny because I as an observer am moving myself
only a complete stationary observer could tell this
I don't think that this is possible so again, we are limited in knowing these things
things we see are affected by our own motion

"""From where? From the planet Mars? From inside a spaceship flying past at half the speed of light? From sitting on object A? Where?"""

There is nothing except Space, one observer and two objects. The observer can only see those two objects. The observer has a space-suit on and is "somewhere" in the dark space doing nothing.

"""Oh? Perhaps you'd like to support that statement with something other than gut feeling, because I've given you lots of reasons why that is not the case, yet so far you've given me no reason why it is the case."""

space is about dimensions
dimensions are like a sea of endless points
each point represents a coördinate which is totally independent of objects

"""You replied, rather cryptically: we don't choose

What????!!"""

Space is entirely objective.

"""I looked [the clock experiment] up and as I initially thought your are wrong.

Wrong about what? Wrong in what way? I don't think so."""

Yes you are wrong. Your statement in that previous post is wrong or the information on that website is incomplete which I don't think. It was a one-way experiment like all the others. If not so, then explain me why this website and all the others give a one-way information about the collected data.

And James R, what about the absolute motion of Light? It seems that there are absolute things ... what would the theory of relativity be without this absolute light? It wouldn't be there. Motion can be absolute just like light shows us. I will be repeating myself if I go further.

"""2) Point A and point B are still in relative motion."""

imagine we would have discovered the aether
we calculate all motion RELATIVE to the absolute aether
so, what's your point?
motion IS relative to space

James R,


"If light always follows an absolute frame of reference, couldn't the absolute speed and direction of an object be measured using lasers??"

There's no such thing as an absolute frame of reference.

That's what you think.



"I believe a device could be built, using three lasers and a gyroscope, which would be able to measure the absolute motion of an object."

Tell me how.

I don't have it completely worked out, but this is a general outline:

The moving object would have two devices.

The first device would be a gyroscope, which would measure any changes in speed and direction of the moving object.

The second device would use three lasers, one for each dimension, to measure the absolute velocity of the object. Because light always travels in the absolute frame of reference, the absolute motion of the object can be measured in two ways:

a) By measuring the curvature of the beams of laser light. If the object is at absolute rest, there would be no curvature of the laser beams. The greater the absolute speed of the object, the greater the curvature of the laser beams.

b) By measuring the time it takes the laser beams to hit their targets. If it takes longer for the beam to hit the target, that would mean that the object is traveling in the same direction as the laser beam. Using the time difference from all three laser beams, the three dimensional absolute velocity of the object can be induced.

Tom

c'est moi:

<i>everyone is free to think and to believe what he wants but it's interesting to discuss these thoughts and believes</i>

Agreed. Some beliefs are mistaken though, as you pointed out in another context.

<i>you, the penny and the floor are moving together as one system
the penny doesn't REALLY follow a straight path nor a curved path
I have no idea what the REAL motion is of the penny because I as an observer am moving myself only a complete stationary observer could tell this</i>

But since there's no such thing as a "complete stationary observer", there's no "REAL motion" which is completely independent of any observer either. So you agree with me, then. Good.

<i>There is nothing except Space, one observer and two objects. The observer can only see those two objects. The observer has a space-suit on and is "somewhere" in the dark space doing nothing.</i>

If we can get you to understand your own example here, we'll make some progress.

You say the observer is "somewhere...doing nothing". That's very non-specific, don't you think. What you really mean is the observer is absolutely stationary relative to some fixed, God-given coordinate system in space. Once again, I have to tell you that there is no such God-given coordinate system. Hence there is no "absolutely stationary" observer. Hence, your example is underspecified.

<i>each point [in space] represents a coördinate which is totally independent of objects</i>

Independent of objects, yes, but totally dependent on an observer and his or her motion.

<i>Space is entirely objective.</i>

Once again, some evidence of this would be nice.

<i>Yes you are wrong. Your statement in that previous post is wrong or the information on that website is incomplete which I don't think. It was a one-way experiment like all the others. If not so, then explain me why this website and all the others give a one-way information about the collected data.</i>

The website is incomplete. I suggest you search for the original paper and read it, rather than somebody's summary of it.

<i>And James R, what about the absolute motion of Light?</i>

What absolute motion of light? Light has the same speed in every inertial reference frame - that is all. That doesn't in any way mean that an absolute reference frame exists.



Prosoothus:

<i>That's what you think.</i>

Yes. That's what I think.

<i>a) By measuring the curvature of the beams of laser light. If the object is at absolute rest, there would be no curvature of the laser beams. The greater the absolute speed of the object, the greater the curvature of the laser beams.</i>

That won't work. The laser beams would not curve at all for an object moving at constant velocity.

<i>b) By measuring the time it takes the laser beams to hit their targets. If it takes longer for the beam to hit the target, that would mean that the object is traveling in the same direction as the laser beam. Using the time difference from all three laser beams, the three dimensional absolute velocity of the object can be induced.</i>

Are the targets fixed to the object in this scenario, or separate from it. If separate, how will you know that the targets themselves aren't moving relative to your "absolute" stationary reference frame?

James R,


"a) By measuring the curvature of the beams of laser light. If the object is at absolute rest, there would be no curvature of the laser beams. The greater the absolute speed of the object, the greater the curvature of the laser beams."

That won't work. The laser beams would not curve at all for an object moving at constant velocity.

You are correct, the laser beams would not curve in an object moving at a constant speed when you compare them to an absolute frame of reference. But when you look at the laser beams from the objects point of view, they will appear to be curving. The "relative" curving of the laser beams can be used to determine the absolute velocity of the object.


"b) By measuring the time it takes the laser beams to hit their targets. If it takes longer for the beam to hit the target, that would mean that the object is traveling in the same direction as the laser beam. Using the time difference from all three laser beams, the three dimensional absolute velocity of the object can be induced."

Are the targets fixed to the object in this scenario, or separate from it. If separate, how will you know that the targets themselves aren't moving relative to your "absolute" stationary reference frame?

The targets would be fixed to the object at a predetermined length from the lasers. Note: The whole device would be able to be rotated in order to confirm that the lengths to the target are accurate.


Tom

Tom,

<i>...the laser beams would not curve in an object moving at a constant speed when you compare them to an absolute frame of reference. But when you look at the laser beams from the objects point of view, they will appear to be curving.</i>

No, they wouldn't curve in the object's frame of reference either.

<i>The targets would be fixed to the object at a predetermined length from the lasers. Note: The whole device would be able to be rotated in order to confirm that the lengths to the target are accurate.</i>

If the targets and lasers are both fixed to the object, then no changes in arrival times of the lasers will occur, provided the object continues to move at constant speed.

You could use this device to measure acceleration, but not "absolute" velocity.

James R,


"...the laser beams would not curve in an object moving at a constant speed when you compare them to an absolute frame of reference. But when you look at the laser beams from the objects point of view, they will appear to be curving."

No, they wouldn't curve in the object's frame of reference either.

You're contradicting yourself. Think about the example of the observer dropping a penny in the train. To the observer in the train, the penny falls straight down, but to the observer outside, the penny curves. The exact opposite would occur if the observer shot a laser beam at the floor of the train. To the observer in the train, the laser beam would curve, but to the observer outside, the laser beam would go straight.

Let me explain it in another way: Say you are travelling at 90% of c and you're holding a laser in your hand. To the right of you there is a target about a 100 meters away. The target is fixed with you, and is travelling at the same speed you are.

If you shot the target with you're laser, you would miss the target completely because by the time the laser beam reaches the target, the target would have moved. Even though the laser beam travelled in a straight line, to you it would appear that the laser beam curved. In other words, in the absolute frame of reference, the laser beam follows a straight path, but in your frame of reference, the laser beam would appear to curve. The amount of "percieved" curvature is directly proportional to the speed you are travelling.


"The targets would be fixed to the object at a predetermined length from the lasers. Note: The whole device would be able to be rotated in order to confirm that the lengths to the target are accurate."

If the targets and lasers are both fixed to the object, then no changes in arrival times of the lasers will occur, provided the object continues to move at constant speed.

If I shoot a laser beam at a target that is moving away from the laser beam, it will take longer for the laser beam to hit the target than it would if the target was stationary. If I shoot a laser beam at a target that is moving towards the laser beam, the laser beam will hit the target sooner than if the target was stationary. The above would occur even if the I was travelling at the same speed as the target, because the speed of the laser beam is always constant, regardless of the speed of the person shooting it.

Tom

If what you say above had any resemblance to reality then particles in accelerators could never interact. Take two electrons travelling parallel to each at 0.9c in an accelerator. They exchange virtual photons (travelling at c) to mediate the electrostatic force. If you where correct the virtual photon could never hit the other electron as the 'target' had moved on and no forces could be communicated.

You're example is trivially falsified.

Thed,

Let me remind you that particles in particle accelerators are very close together. This is why they still react to each other at high speeds. In other words, the "virtual" photon exchange happens faster than the particles can move out of the way.

Are you suggesting that the virtual photons are traveling faster than light?? Or are you saying that the speed and direction of virtual photons are relative to the frame of reference of the particles that are producing them???


Tom

Now I get it, a photon won't hit a perpendicular target because light bends except when they are too close. And you're evidence for this astounding insight is?

How the photon did you infer that I implied virtual photons travel faster than light or are relative to the FOR producing them. Again, learn what is meant by 'the speed of light is invariant'.

Thed,

Thanks for avoiding my question.

Like usual, I give my idea, you claim that it's wrong without indicating why it's wrong or giving me your explanation.

How convenient for you.

Note: Let me remind you, I don't post messages on sciforums to argue with people. I'm after the truth, just like I think you are. When I post an idea and someone believes that it is wrong, I would appreciate if that person explains that:

a) My facts are wrong
or
b) My conclusion, based on my facts are wrong.

Unfortunately, again, you provided neither.

Tom

Hi Tom,

<i>You're contradicting yourself.</i>

No I'm not. You're just not understanding.

<i>Think about the example of the observer dropping a penny in the train. To the observer in the train, the penny falls straight down, but to the observer outside, the penny curves. The exact opposite would occur if the observer shot a laser beam at the floor of the train. To the observer in the train, the laser beam would curve, but to the observer outside, the laser beam would go straight.</i>

No. To both observers, the path of the laser beam would be straight. If the observer in the train shot the laser beam towards the floor, the beam would be a vertical line from his point of view. An outside observer would see a slanted line, but not a curved one.

<i>Let me explain it in another way: Say you are travelling at 90% of c and you're holding a laser in your hand. To the right of you there is a target about a 100 meters away. The target is fixed with you, and is travelling at the same speed you are.

If you shot the target with you're laser, you would miss the target completely because by the time the laser beam reaches the target, the target would have moved.</i>

No. If the target is travelling along with you, if you aim at the target you will hit it, no matter how far away. Sure, the target moves, but the light has horizontal motion as well, which means it keeps pace with the target.

<i>Even though the laser beam travelled in a straight line, to you it would appear that the laser beam curved.</i>

No, you'd see it travel in a straight line.

<i>In other words, in the absolute frame of reference...</i>

There is no absolute frame of reference.

<i>If I shoot a laser beam at a target that is moving away from the laser beam, it will take longer for the laser beam to hit the target than it would if the target was stationary.</i>

Yes, but not if the target is a fixed distance away from the source of the beam, like you said it was before.

<i>The above would occur even if the I was travelling at the same speed as the target, because the speed of the laser beam is always constant, regardless of the speed of the person shooting it.</i>

Wrong. If the target is a constant distance away from the source, the travel time for the light will be constant, regardless of whether the source and target are moving or not.

damned :(

I had answered your post James R, which took me quite some time. When I hit the "reply" button, I was suddenly asked to login even though I was already. Instead of going back and save the content of my post, I logged in, suspecting nothing, and I got taken to a non-specified page. I went back with my browser and my post was gone and wasn't posted either.
I decided afterwards to type it again, and in a little different way, somehow the same thing happens. Now I have found the problem (it's my PC) but I don't feel like going through it again .... maybe in a few days. This really frustrating.

James R,


No. If the target is travelling along with you, if you aim at the target you will hit it, no matter how far away. Sure, the target moves, but the light has horizontal motion as well, which means it keeps pace with the target.

Your right and wrong at the same time. The light would move horizontal and forward at the same time, but if the target was moving very fast, the light couldn't catch up because the light would have to travel forward and horizontal, while the target would only have to move forward.

Check out this link I found:

http://www.physics.wustl.edu/~visser/physics-216/notes-light-clock.html

It demonstrates a device that would give the absolute speed of an object. If you count the amount of times the laser bounces off the two mirrors in this device, you can get the absolute speed of an object. The faster the object would go, the fewer times the laser beam would bounce of the mirrors per second.(Of course, you would need three of these, one for each dimension)

I guess this device would not only prove that there is an absolute frame of reference, but it would also measure the absolute speed of any object. So much for relativity!! :)

Tom

In fact, it's all very logic. Light's speed is constant so it can be used as an absolute FOR. Imagine that light wouldn't move at all, then anyone would see that it could be used as abs. FOR, but now it is like the fastest moving thing we know of, which changes the situation, but it remains the same: constant speed means FOR which is independant, hence absolute
James R, you may come up with objections against how to built such a device but I'm sure such a device can be built
however, as long as no one has built one and tested it, we both can't be sure

I recommend you to read the book:
<B>"The elegant Universe" by Brian Greene.</B>

Groove on.

:)

Tom,

<i>Your right and wrong at the same time. The light would move horizontal and forward at the same time, but if the target was moving very fast, the light couldn't catch up because the light would have to travel forward and horizontal, while the target would only have to move forward.</i>

The light will always "catch up", since in any frame of reference the target, which has mass, must travel slower than the speed of light.

<i>Check out this link I found...</i>

Did you check it out? It supports relativity. In fact, it is used to derive a relativistic formula.

<i>If you count the amount of times the laser bounces off the two mirrors in this device, you can get the absolute speed of an object. The faster the object would go, the fewer times the laser beam would bounce of the mirrors per second.(Of course, you would need three of these, one for each dimension)</i>

No, that's wrong. In the frame of reference of the mirrors, there will be no variation in the number of times light bounces backwards and forwards, regardless of speed.

<i>I guess this device would not only prove that there is an absolute frame of reference, but it would also measure the absolute speed of any object. So much for relativity!!</i>

So much for relativity if you were right, but fortunately for relativity, you're wrong.


c'est moi:

You're still confused about reference frames. A reference frame involves two things: <b>space</b> (or distance) and <b>time</b>. In order to measure a <b>speed</b>, we need to have a pre-defined spacetime reference frame. Given a reference frame, any object then has a particular speed. Change the reference frame and, usually, the speed of an object changes.

For example, when you're driving in your car, the speed of the car in the reference frame of the road might be 60 km/hr. In your reference frame, sitting in the car, the car's speed is zero.

The funny thing about light is that its speed is the same in all reference frames. The only way that is possible is if different observers' ideas of space and time are different depending on their frame of reference - an idea which leads us automatically to the theory of relativity.


Gil_W:

Thanks. I've read it.

James R,

Read the link again.

If the speed of light is constant, and if you increase the horizontal velocity of the light in the device by moving it, the vertical velocity of the light must slow down in order for the light's speed to remain constant.

If you increase the horizontal velocity of light without decreasing the vertical velocity, the light would be travelling faster than c.

This concept doesn't take a lot of thought, it's common sense.

Tom

Just one more thing:

The relativistic properties of frames of reference are not the result of there being no absolute frame of reference, but the result of the absolute frames of reference cancelling each other out.

Tom

Tom,

<i>If the speed of light is constant, and if you increase the horizontal velocity of the light in the device by moving it, the vertical velocity of the light must slow down in order for the light's speed to remain constant. If you increase the horizontal velocity of light without decreasing the vertical velocity, the light would be travelling faster than c.</i>

Yes. I agree with that.

<i>The relativistic properties of frames of reference are not the result of there being no absolute frame of reference, but the result of the absolute frames of reference cancelling each other out.</i>

How? Explain.

The relativistic properties of frames of reference are not the result of there being no absolute frame of reference, but the result of the absolute frames of reference cancelling each other out.

Absolute frames of reference cancelling each other out? Multiple and opposing absolute frames of reference?

James R, and Adam,


The relativistic properties of frames of reference are not the result of there being no absolute frame of reference, but the result of the absolute frames of reference cancelling each other out.

Let me explain:

In a relative frame of reference:

Vr=V1-V2

where Vr is the relative velocity of object 1 compared to object 2
V1 is the relative velocity of object 1
V2 is the relative velocity of object 2

If the observer is object 1 then the observer can give the value of 0 to V1 in order to determine the relative speed of object 2 compared to himself/herself.

However if you assume that there is an absolute velocity(a) that the entire frame of reference is traveling at, you get the formula:

V=(V1+a)-(V2+a)

As you can see Vr from the first formula is equal to V in the second formula. As you can also see, the absolute velocities of the observer and object cancel each other out in the second formula, regardless of the actual value of a.

Tom

Yes, that's right, Tom. Therefore, the concept of a is superfluous. There is no absolute reference frame.

Also, you have to realise that v1 and v2 must be relative to something as well, unless they are meaningless.

James R,

You're wrong.

If you dropped a rock on your foot, you would be able to determine it's acceleration without knowing the mass of the rock(ignoring air resistance, of course).

In this case the mass of the rock in the two formulas

F=m1*m2*g/d^2

A=F/m1

cancel each other out.

This DOES NOT mean that the rock doesn't have mass.

Tom

Mass is a necessary and useful concept for other reasons. An absolute frame of reference is neither needed nor useful.

James R,

Just because something may not be needed or useful, doesn't mean that it doesn't exist.

Tom

Hi Tom,

"Just because something may not be needed or useful, doesn't mean that it doesn't exist."

True. But if you can't touch it, smell it, handle it, it is not needed and not useful, then there is a good reason to just disregard the idea as one of those wierd things you came up with when smoking too much pot (that's the answer to most of my ideas anyway :))

Bye!

Crisp

"""True. But if you can't touch it, smell it, handle it, it is not needed and not useful"""

--> dark matter
--> dartk energy

some leading scientists are on the pot, I knew it all the way


"""You're still confused about reference frames."""

obviously, the only thing you seem to come up with is to say that I am confused and repeat the thing all over

"""Given a reference frame, any object then has a particular speed. Change the reference frame and, usually, the speed of an object changes. """

okidoki

"""The funny thing about light is that its speed is the same in all reference frames."""

yes, very funny
what's even more funny is that because of this we could use it as an abs FOR
somehow, you seem to completely miss the point here
say clearly why we can't use light as abs FOR for everything that moves ... why oh why thou Lord?

<i>what's even more funny is that because of this we could use it as an abs FOR somehow</i>

Somehow? How?

That would be for physicians specialised into devices and experiments to find out.

This one says it can't be done. Relativists 1, Absolutists 0.

Hi c'est moi,

Short summary of the previous posts:

c'est moi: yes, very funny ; what's even more funny is that because of this we could use it as an abs FOR. somehow, you seem to completely miss the point here say clearly why we can't use light as abs FOR for everything that moves ...

James R: Somehow? How?

c'est moi: That would be for physicians specialised into devices and experiments to find out.

So at first you say that there is an absolute frame of reference that you can't specify. Then you ask the same physicists to find it, even when they all agree that there is no absolute frame of reference.

Hrmmmm ?

Bye!

Crisp

Crisp, I did specify it: LIGHT
bad summary