# Light Drive.

Discussion in 'Physics & Math' started by Jolonar, Jul 5, 2004.

1. ### HeadacheI drink therefore I amRegistered Senior Member

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a ship tha t was already under acceleration, from breaking gravity would already have some inertia, and would only require a moderate photon force acting apon a light sail to continue the acceleration,and the acceleration would be cumulative in the vaccum of space.......

3. ### Brandon9000Registered Senior Member

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You appear to have never seen a book on special relativity. If you left the Earth travelling at 99% the speed of light, and someone on the Earth aimed a flashlight at you, you would see the light from the Earth approach you at 100% the speed of light, not 1%. All observers will measure light as propagating at the speed of light, regardless of their relative motion to the source. You need to use the relativistic, not the classical, velocity addition formulas.

All of your comments concerning what an observer travelling at or faster than the speed of light would see are incorrect, since nothing composed of matter can accelerate to the speed of light.

Cite your sources for these claims.

5. ### Brandon9000Registered Senior Member

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Well, you could find this in any number of books about special relativity, but I'll summarize. In order for an object to reach the speed of light, it has to be accelerated to that speed. As the speed of the object increases, its mass increases, so that each additional mile per hour of speed requires more energy than the previous mile per hour of speed. To actually accelerate an object - even one atom or electron - to the speed of light would require an infinite amount of energy.

It makes no sense to make assertions about areas of Physics that you are not familiar with, any more than it would make sense to critique techniques of brain surgery without studying biology or medicine.

7. ### swansontRegistered Senior Member

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The total energy of a massive particle is m0c^2/sqrt(1-v^2/c^2)

Subtract the rest energy, m0c^2, and the rest is the kinetic energy in free space.

8. ### Brandon9000Registered Senior Member

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In 1905, Einstein showed that no material object may be accelerated to the speed of light, and this has been accepted by essentially all physicists on Earth for about a century. You can find the math in college textbooks all over the world, but I will refer you to Einstein's paper:

http://www.iitk.ac.in/phy/phy102N/Einsteins_paper_relativity.pdf

9. ### Brandon9000Registered Senior Member

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Many people, when losing an argument, will respond by attempting to change the subject, or introduce additional subjects. I won't allow you to change the subject until the first point is resolved. I said that no material object can accelerate to the speed of light, because it has been accepted by the world scientific community for a century. You are clearly discussing a topic of which you have no comprehension.

10. ### Brandon9000Registered Senior Member

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1. Atoms can emit photons. The photons emitted travel at the speed of light. The atom, however, cannot be accelerated to this speed. If one attempted to do so, the equations of special relativity show that the energy required would be infinite.
2. The process by which the photon is created is unknown.
3. You have failed to define what you mean by induction. Please do so. I refuse to argue with someone who will not define his terms. Also, explain what you mean when you say that the rate of induction of light is greater than the speed of light.
4. Which energy are you referring to exactly in your last sentence, when you refer to the energy producing the light, and what do you mean when you refer to this energy's speed?
5. It appears to me that you have no familiarity with this topic. Do you, and if so, what is your background? Why do you believe that you are qualified to argue the fine points of quantum electrodynamics with no knowledge of the subject? While any argument can be discussed based on its merits and not its origin, it is simply foolish for someone with no knowledge of physics to dispute accepted theory. Theories in physics are not often disproved by people who have not taken the trouble to learn them.

11. ### Brandon9000Registered Senior Member

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The fact that atoms emit light, does not in any way imply that atoms can be accelerated to the speed of light. Atoms in materials which are not even in motion at all emit light. You appear to be implying that at some point in the process of the creation of the photon the atom is emitting, there is some material object travelling faster than light, but you only hint at this vaguely, with no explanation. Explain.

Words defined in dictionaries rarely have much resemblance to the way the words are used in science, unless the dictionary chooses to include a scientific definition. My Merriam Webster dictionary defines the word induction as follows:

Which of these definitions corresponds to the way you are using the word? None seems to fit. Are you afraid to define your terms? That's hardly a characteristic of someone who is right.

What do you mean by "rate of force?" What do you mean by "rate of induction" (assuming that at some point you define induction)? What do you mean by an object exchanging energy with a direction?

Furthermore, at any given speed, the kinetic energy of an object is given by the formula:

E = mc^2[1/(1-v^2/c^2) - 1]

where m is the rest mass. As you can see, as the speed approaches that of light, the kinetic energy of the object approaches infinity. Where do you propose to get an infinite amount of energy?

If you are correct in your belief that material objects can be accelerated to or beyond the speed of light, it would be a huge revision of a century old accepted theory. It would be news worldwide. Do you plan to publish your work in any actual scientific journal? May I suggest "Physical Review?"

Despite your colorful debating technique, it is clear that you have no credentials of any kind in this subject. If I am wrong, merely tell me what your credentials are. This is not art criticism. You actually have to know something about this subject to discuss it meaningfully.

12. ### NasorValued Senior Member

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Brandon9000: Welcome to scifourms.

Don't bother trying to argue with DwayneD.L.Rabon. He's a total crackpot who has lurked around here for some time. In arguing with him you are making the mistake of assuming that if you present your (correct) arguments in a clear and logically sound manner that he will be convinced. This is futile, because like most crackpots his 'understanding' of physics is so radically different from the mainstream that he doesn't even use basic terms in the same way. It's nice of you to try to educated him, but he isn't really interested in being educated; he will simply ignore anything that you tell him if it doesn't fit with his bizarre views. Trust me, you won't get anywhere. Trying to argue with him only encourages him and pollutes threads with off-topic discussion.

13. ### Brandon9000Registered Senior Member

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Thanks for the welcome and the 411 Nasor. I have followed your posts in this and other forums at this site with interest since I arrived here. I look forward to speaking to you in the future.

14. ### CrispGone 4everRegistered Senior Member

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Oh no, not another one...

15. ### 1100fBannedRegistered Senior Member

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807
At least you have a hint for the answer in your question. Since the rate of induction must be greater than the speed of light, they must have the same dimension in order to compare them. Since the speed of light has dimension [length]/[time] and the rate of induction has dimension:[Induction]/[time], obviously the dimension of Induction is length.

What is this length?
Well in the same way that mass (in nonrelativistic physics) is defined in Newton's second law of motion, the induction is defined in "DwayneD.L.Rabon" laws of motion:
I have allways thought that for an object to travel from one point to another it must have a velocity.
Silly me!!!!
How couldn't I notice that it must have a rate of force and a rate of induction?
I must be realy stupid.

Since I am so stupid, please, DwayneD.L.Rabon, can you explain me from Maxwell's equations &part;<sub>&mu;</sub>F<sup>&mu;&nu;</sup> = 4&pi;j<sup>&nu;</sup> and &part;<sub>&mu;</sub>F<sup>*&mu;&nu;</sup> = 0, how do you get that the source of the em waves (the photons) must move with the speed of light (i.e. j<sup>&mu;</sup>j<sub>&mu;</sub> = 0)?

Last edited: Jul 14, 2004
16. ### 1100fBannedRegistered Senior Member

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807
Once you get used to the old ones, then new ones appear.
Question:
Is this a spontaneous emission of crackpots or a stimulated emmision of crackpots.
In my believe it is both.
Now, if we put them all together in a resonant cavity, by using population inversion with both the stimulated emiision of crackpot, I am sure that we could make a very powerful weapon that I call BASEC (BS Amplification by Stimulated Emission of Crackpot), or even better: BASIC (BS Amplification by Stimuated Induction of Crackpots).
I really like the word "induction"

Last edited: Jul 14, 2004
17. ### RawThinkTankBannedBanned

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429
So a rocket travels at 99% speed of light and light is send towards it after 99 years then will it reach the rocket within one years ? that’s because for the rocket light will travel at light speed and not at 1% speed of light.

18. ### Brandon9000Registered Senior Member

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All of your numbers are wrong, but my point was that if any observer measures something, such as a light beam, as travelling at the speed of light, then all observers will measure that things as travelling at the speed of light, no matter what their relative motion.

Earth bound observers sending out the light beam will see it propagating towards the space ship at 100% the speed of light, and people in the space ship will see it approaching them at the speed of light, no matter what the velocity of the space ship relative to the Earth.

19. ### CrispGone 4everRegistered Senior Member

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1,339
Very sad indeed. Oh well, it just takes away the fun of posting on this particular forum, which is something I think is true for many of the more educated people who keep this forum running (on the level of physics)

20. ### RawThinkTankBannedBanned

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So U r saying that a ship traveling with the light at 99% speed of L will also seem to reach early for the first ship ? I mean why only light, whats so special about it ?

21. ### 1100fBannedRegistered Senior Member

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There is nothing special with the speed of light.
The nature of space-time is such that there is a speed which is invariant under all reference frames. That is, the nature of space time is such that intervals are invariant under Lorentz transformations. All massless particles travel at this speed. Light being massless will also travel at this speed. Light is an electromagnetic phenomenon. Since the everyday life is governed by electromagnetism, light was the first thing that was discovered to travel at this invariant speed (from this the name of speed of light). Gravity is not strong enough to be felt (except for very large bodies such as the earth). The strong nuclear force is much stronger than the em force however it is of very short range and this is the reason why we don't feel it in the everyday life, however the mediators of this force are massless and travel also at the speed of light.

22. ### Brandon9000Registered Senior Member

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As the previous poster pointed out, it has been known since Einstein's first relativity paper in 1905 that if any unaccelerated observer measures the speed of something as being C, then all unaccelerated observers will measure the speed of that thing as being C. This is true even if the two observers are in motion relative to each other. C is a special speed that has this property. Light is an example of something that propagates at this speed. This has been verified experimentally countless times over the past century and is one of the two postulates from which relativity was derived.

23. ### HeadacheI drink therefore I amRegistered Senior Member

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It seems that the topic is "light drive".... now this has been discussed as travelling at the speed of light, then there was the endless debate and banter whilst some of us came to grips with relativity.... If I read one more post that starts with......" so theres this guy , right...and he's on a rocket going away from earth at the speed of light...."
I'm going to stick thumbtacks in the roof of my mouth.

The speed of light is the general road rules for the universe as we know it so far,
for mass to be accelerated to that speed would require infinite energy.Look at what happens at the event horizon of a black hole, any mass unfortunate enough to be caught in the gravitational field is accelerated,not only in distance but slowed down proportionately in time as well.
In the brief instant before an unlucky astronaught fell beyond the horizon, he would witness the fate of the universe in fast forward, just before he was stretched ad infinitum.

There have been some theories, proposing the use of space itself to reduce the profile of the mass of the craft itself, a la "Dr Whos Tardis" whereby a microscopic object can travel vast distances unhindered by its mass, but on the inside can be large enough to hold occupants.

Does anyone else think that the key lies not with light , but with space/time and gravity?

p.s Rabon, PLEASE USE SPELLCHECK OR SOMETHING, YOU LOOK RETARDED FROM HERE