The Mystery of Light: FTL Travel

theurinal
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Firstly, just a high to everyone, (first post, aye).

Now, everyone has been saying that FTL Travel (Faster than Light) and even the speed of light is impossible. (dammit... ) than how is it that light can go at the speed of light.

Now, for some touching back on the SOL theory. As you approach the SOL time gets slower and the energy needed for the speed gets higher. AT the SOL energy is infinite and time is held. (e.g 12:00 forever: never even hitting 1 ms later)

Now, if the energy required is infinite than how can Light itself go that fast.

Is the secret hidden in Light??!
 
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Originally posted by theurinal
Is the secret hidden in Light??!
The secret is that light has no mass.
 
Originally posted by theurinal
Firstly, just a high to everyone, (first post, aye).

Now, everyone has been saying that FTL Travel (Faster than Light) and even the speed of light is impossible. (dammit... ) than how is it that light can go at the speed of light.

Now, for some touching back on the SOL theory. As you approach the SOL time gets slower and the energy needed for the speed gets higher. AT the SOL energy is infinite and time is held. (e.g 12:00 forever: never even hitting 1 ms later)

Now, if the energy required is infinite than how can Light itself go that fast.

Is the secret hidden in Light??!

AS he said light has no mass. It is an electromagnetic fluctuation. think of light as an increase in the electromagnetic field that moves throuhg space. This fluctuation can only propagate at the speed of light. It has no mass so the rules about accelerating to that speed are irrelevant. Also there is no known reason why it travels at that speed, it just does.
 
oh ok. i didn't really know that... well a day in which you learn something isn't a day wasted...

thanx guys
 
There is a common misunderstanding about the speed of light being the limit of all physical speed. The actual limit is the the speed that a mass can be accelerated relative to the accelerating energy source. Since electromagnetic waves (light) is the fastest means of transferring energy it appears to the energy source as if the mass is increasing without bound as speed approaches light speed. Actually if some energy source is already traveling near the speed of light relative to some other object it can still accelerate another mass in the same direction producing greater than light speed relative to the first object. As a result the only limit on the speed of a rocket is the limited energy (and ejectable mass) it carries with it.
 
Actually if some energy source is already traveling near the speed of light relative to some other object it can still accelerate another mass in the same direction producing greater than light speed relative to the first object. As a result the only limit on the speed of a rocket is the limited energy (and ejectable mass) it carries with it.

Absolutely wrong, and often refuted on these boards. Learn relativity.
 
- - moving this to the Relativity forum - -
 
Originally posted by Nudnik
There is a common misunderstanding about the speed of light being the limit of all physical speed. The actual limit is the the speed that a mass can be accelerated relative to the accelerating energy source. Since electromagnetic waves (light) is the fastest means of transferring energy it appears to the energy source as if the mass is increasing without bound as speed approaches light speed. Actually if some energy source is already traveling near the speed of light relative to some other object it can still accelerate another mass in the same direction producing greater than light speed relative to the first object. As a result the only limit on the speed of a rocket is the limited energy (and ejectable mass) it carries with it.


Umm...yeah. You can't just add velocities straight like that. The correct formula for adding velocities ( don't recall off hand) does not allow for the sum to exceed the speed of light. Just as the speed of light in a vacuum is a constant irrelevant of the motion of the observer, at the same time the sum of two velocities is limited to the speed of light irrelavant of the speed of the observer. This is dictated by the Lorentz transformations which are in turn dictated by the minkowski metric which describes spacetime in the absence of gravity (Special Relativity).
 
I gave a physical process for why the mass increase is only apparent. How about you giving a physical process for why velocities can't be added (not just a mathematical speculation). [:>)]
 
  • #10
Originally posted by Nudnik
I gave a physical process for why the mass increase is only apparent. How about you giving a physical process for why velocities can't be added (not just a mathematical speculation). [:>)]
How about 100 years of experimentation in electromagnetics?
 
  • #11
How about it? [:>)]
 
  • #12
A good example is a particle accelerator. They put tons and tons of energy into a proton (or other small particle) and only get it asymptotically closer to C. Einstein's relativity is not just "mathematical speculation."
 
  • #13
You didn't read my first post. Remember that in the accelerated particles rest frame its mass is still rest mass. Where is the increased mass. It only looks to the accelerator (or any observer at rest relative to the accelerator) as if the mass has increased because the particle is tending to outrun the means of energy transfer (or information transfer).
 
  • #14
Originally posted by Nudnik
How about it? [:>)]
Electromagnetic energy propagates at speed c away from its source. This is true regardless of how fast the source is moving or how fast the observer is moving.
 
  • #15
Originally posted by turin
Electromagnetic energy propagates at speed c away from its source. This is true regardless of how fast the source is moving or how fast the observer is moving.

Tha manner of that statement shows, beyond any shadow of doubt, that you don't have a clue. The idea of relativity is just that. RELATIVE. {;>)] ~
 
  • #16
Originally posted by Nudnik
Tha manner of that statement shows, beyond any shadow of doubt, that you don't have a clue.
By all means, enlighten me. Which part of my last statement of incorrect? I will admit that I have not performed exhaustive experimentation to validate my last statement, but the experiments I have done have demonstrated it. I have also been taught the same thing in all of my academic education. So, I would certainly like to hear why you think that it is incorrect. Has there been an experiment that falsifies the invariance of Maxwell's equations under a Lorentz transformation?
 
  • #17
Electromagnetic energy propagates at speed c away from its source. This is true regardless of how fast the source is moving or how fast the observer is moving

Electromagnetic energie propagates at speed c in every inertial system.
When the source is moving with a speed v in te observers systems, lights propagate at speed c for the observer, but the relative velocity between the light and the source isn't c, but c-v (if v is small). The observer who travels with the source, sees that the light is going away from the source with light speed.
 
  • #18
I think we are getting a definite maybe on this subject.

Maybe some light shift would help:

Take two observers, one on Earth and one on Earth'. They are two billion light years apart. Exactly halfway between the two planets is a galaxy (8C1435+635). It is .93C red shifted to Earth and blue shifted a like amount to Earth' indicating a movement away from Earth and toward Earth'. Strictly from the perspective of the observers on Earth and Earth', and these observers only, take a simultaneous emission of a beam/wave/photon leaving the exact center of 8C1435+635 at the same instant moving toward these planets. From a number of discussions it appears the .93C red shifted light will arrive at Earth in the same instant the blue shifted light will arrive at Earth'.

No other observers are allowed. We don't care about an observer on 8C1435+635. Assume ideal vacuum along both paths with no intervening mass. Is there general consensus the arrival times would differ or arrival times would be identical?
 
  • #19
If they did arrive at the same instant, should the red and blue shift be so pronounced?
 
  • #20
Where does the doppler shift occur, at the source, at the observer, half at the source and half at the observer or gradually along the way?
 
  • #21
I don' t think the dopler effect is essential in this question. It only says that the galaxy is moving towards earth'.
Sinds there are only two observers, there are two answers
Observer 1 on Earth detect the redschited beam first and after (a long) time he see that the other beam reaches earth'(because the reflection of the hit has to travel from earth' to earth.
The observer on eart'see it the other way around.
simultaneous doesn't exist in special relativity. It always depend from the observer which events take place together.
 
  • #22
______________________________________________________________
Take two observers, one on Earth and one on Earth'. They are two billion light years apart. Exactly halfway between the two planets is a galaxy (8C1435+635). It is .93C red shifted to Earth and blue shifted a like amount to Earth' indicating a movement away from Earth and toward Earth'. Strictly from the perspective of the observers on Earth and Earth', and these observers only, take a simultaneous emission of a beam/wave/photon leaving the exact center of 8C1435+635 at the same instant moving toward these planets. From a number of discussions it appears the .93C red shifted light will arrive at Earth in the same instant the blue shifted light will arrive at Earth'.
________________________________________________________________

Alrighty then, let’s take a little different spin. The light is emitted at the point source (galaxy 8C1435+635) at wavelength X. Let the "frequency" shift in the wavelength of the light receding/approaching at .93C be Y. So the Frequency of light on Earth would be X - Y and Earth' X + Y. How is the drastic alteration in properties of the original light source accounted for? Does it mean the photon arrives at exactly the same instant on both Earth and Earth' but parts of the receding (Earth') photon arrive later and parts of the approaching (Earth') photon arrive a little sooner?
 
  • #23
Originally posted by meddyn
We don't care about an observer on 8C1435+635.
Speak for yourself (and other people of like mind). In this discussion, all three perspectives are valid.




Originally posted by Peterdevis
simultaneous doesn't exist in special relativity. It always depend from the observer which events take place together.
Simultaneity exists just as much as spatial distance, temporal time, or 3-velocity in SR.

Actually, a better analogy would be, if you can't say "simultaneous" in SR then you can't say "at rest" in SR either.
 
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  • #24
Sure you can say at rest in SR. Every inertial observer can cll herself at rest. And her frame (in the small limit) is Galilian.
 
  • #25
quote:
----------------------------------------------------------------------Originally posted by meddyn
We don't care about an observer on 8C1435+635.
----------------------------------------------------------------------

Speak for yourself (and other people of like mind). In this discussion, all three perspectives are valid.

_______________________________________________________________

Thank you for your response. That shed a great deal of light on the subject and helped clarify technical points.
 
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  • #26
Originally posted by selfAdjoint
Sure you can say at rest in SR. Every inertial observer can cll herself at rest. And her frame (in the small limit) is Galilian.
Good job. Is that any more valid than saying two events are simultaneous?




Originally posted by meddyn
That shed a great deal of light on the subject and helped clarify technical points.
Likewise.
 
  • #27
Ok, simultaneous exists just like in rest exist, but you have always to say for which observer. So the question of meddyn is meaningless if you don't ask for which observer.
 
  • #28
Thank you Peterdevis. Good reply.

Could we say we had a third observer located at 8C1435+635. Would this observer see the arrival at both Earth and Earth' without any discernable difference.

Some of us are not as gifted/educated in this area and may ask something we consider logical and of interest. The intellectual gap is freely acknowledged and is one of the attractions of an open forum. So we (the less gifted) stand in awe of the gifted seeking insight and wisdom. Your understanding replys are appreciated.
 
  • #29
Originally posted by meddyn
Could we say we had a third observer located at 8C1435+635. Would this observer see the arrival at both Earth and Earth' without any discernable difference.
If an observer moving with 8C1435+635 could somehow magically know when the light signals arrived, then the observer would see the arrival at Earth' first. If the same observer had to wait until a reflection or response signal returned to him/her, then the reflection or response signal would arrive from Earth' first.
 
  • #30
Thank you.
 
  • #31
Originally posted by Nudnik
Where does the doppler shift occur, at the source, at the observer, half at the source and half at the observer or gradually along the way?
I would say half and half, though I am not intending to mean half in the numerical sense, just that is is divided. I drew up a couple of gifs to demonstrate. Please let me know if anything is unclear.
 

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  • #32
Excellent document. A lot of work (that is appreciated) and certainly illustrates the point.

This also gives a good area for thought and additional reading:

_______________________________________________________________

the classical effect of the finite speed of light as well as the relativistic effects of the Lorentz transformation must be taken into account in this case. Otherwise, there would not be agreement without establishing an ether frame.
_______________________________________________________________
 
  • #33
Thanks Turin. Your world line diagrams are pretty well in line with SR but please note that C is the same in each reference frame at the same time. Indeed in SR it is the same at all places in each and every reference frame at the same time. Logically that means that it is entirely a matter of point of view. Experimental evidence says otherwise. The Michelson-Morley experiment, on which the idea of constant everywhere in any reference frame is based, does not give any evidence for anywhere except at the observer. And Fizeau's experiment shows clearly that the speed of light is not necessarily constant relative to the observer other than at the observer. Moreover aberration of starlight accomplishes exactly what Michelson-Morley failed. By means of observations on light it shows the Earth's motion in its orbit.
 
  • #34
Originally posted by Nudnik
... aberration of starlight accomplishes exactly what Michelson-Morley failed. By means of observations on light it shows the Earth's motion in its orbit.
Aberation in SR does not dispute the constancy or isotropy of c; contrarywise, it supports it. And Michelson and Morley were not simply trying to show evidence of the Earth's orbit; that would be silly. What they were trying to show was movement through an electromagnetic field medium. This they falied in doing.

Describe a measurement that is perfomed at a point at which there is no observation.
 
  • #35
Yes, they were trying to show movement through an electromagnetic medium. The specific movement in question was the Earth's orbit.
Yes, I know that Einstein fitted aberration into his scheme. But he neglected that it shows a change of relativity between space and the Earth environment.
 
  • #36
Originally posted by Nudnik
Yes, they were trying to show movement through an electromagnetic medium. The specific movement in question was the Earth's orbit.
The motion of Earth in its orbit was known (or at least strongly suspected) long before Michelson was even born. Of course, if you go too far back into history, the notion becomes dangerously heretical. Anyway, the primary mechanism for showing the motion of the Earth with respect to its own orbit is parallax, not aberration. This was known at the time of Michelson. When they did the experiment near the turn of the century, they took the motion of the Earth for granted. Are you trying to say that the null result was evidence against the Earth's orbit? I don't understand what you're trying to convey.




Originally posted by Nudnik
... I know that Einstein fitted aberration into his scheme.
I didn't know that, but I'll take your word for it. It seems reasonable.




Originally posted by Nudnik
But he neglected that it shows a change of relativity between space and the Earth environment.
I don't understand.
 
  • #37
Duh. Of course they were not trying to prove that the Earth was orbiting. They were trying to detect the Earth's motion in the experiment to show the presence of ether. Are you trying to be contrary or do you really not understand ordinary english?

The change of direction of light relative to the observer due to the orbital motion shows that the speed of light is not constant relative to the observer while it is in space but becomes constant relative to the observer on entering the Earth environment which is at rest relative to the observer.
 
  • #38
Well, I had just typed up a monster of a post, but then my session expired. Y'all probably didn't want to read all that crap anyway.

Nudnik,
My intention is certainly not to be contrary. I am thinking that one of us may be a bit confused about one of at least three relevant issues: 1) SR, 2) aberration, and/or 3) Michelson-Morley exp. Let's investigate, shall we.

1) SR declares that it is our cherished notions of absolute space and time that must be thrown out in order to accommodate the constancy of the speed of light. Really, this is a sub-postulate. The laws of physics must remain invariant under a transformation from one IF to any other, and therefore there must be an invariant speed, c. Of course, this is in hindsight, and, at the time, Einstein had to declare it as a postulate in order to preserve the sanctity of Maxwell's equations, which is now taken for granted (due to overwhelming exp. agreement). So, if light speed is seen to be a constant on Earth, and something must be thrown out in order for it to be constant in space, then this something is thrown out in SR. Do you argue against SR?

2) Aberration deals with a moving source, not a moving observation point. Granted, SR allows these two situations to be swapped, but in any case, isotropy is inherently obviated by relative motion.

3) The Michelson-Morley exp. does not involve aberration. They used a source (5900 Angstrom Na) that was stationary WRT the apparatus. The length and time scales involved (notwithstanding the extensive amplification by repeated reflections) were sufficiently small to allow for treatment of SR to a high fidelity.

Let me know where you disagree, or if you think I'm getting way off track here.

EDIT:
Oh yeah, I almost forgot, I wanted to elaborate a bit more on the "motion through the ether is the motion of the Earth's orbit" point. They were not trying to show motion through the ether as orbital motion. In fact, the exp. was performed at opposite times of the year in order to ensure that the Earth's orbital motion was not cancelling out the motion through the ether.
 
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  • #39
(1) Yes

(2) No, aberration of starlight does not involve a moving source but a moving observer. A telescope has to be aimed with an offset angle because of the Earth's orbital motion. Look it up. This shows clearly that light has at least two different speeds relative to the observer in the same frame of reference (the observer's rest frame).

(3) Your comment so misses the point that I won't comment further on it.

If there were an ether the Michelson-Morley experiment could never have detected it because it is logically flawed. The light in the experiment is isolated from space. An enclosed vacuum is not equivalent to space. Maxwell's equations suggest there could be a luminiferous ether but do not require it. That is, the electric and magnetic parameters (permitivity and permeability) could be properties of an ether or they could be properties of the fields and not exist in the absence of those fields.
 
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  • #40
A telescope has to be aimed with an offset angle because of the Earth's orbital motion. Look it up

Don't want to get in the middle of this one but could you please give a reference on this?

Tks.
 
  • #41
Originally posted by Nudnik
(1) Yes
Oh. I was asking that as a rhetorical question. But since you argue against it, I don't think we will have very good discussions, you and I, and you obviously hold grievances against (2) and (3). No disrespect intended, but I won't be responding any more.
 
  • #42
Originally posted by Nudnik

If there were an ether the Michelson-Morley experiment could never have detected it because it is logically flawed. The light in the experiment is isolated from space. An enclosed vacuum is not equivalent to space. Maxwell's equations suggest there could be a luminiferous ether but do not require it. That is, the electric and magnetic parameters (permitivity and permeability) could be properties of an ether or they could be properties of the fields and not exist in the absence of those fields.


The MM apparatus was resting in the earth’s local ether.
 
  • #43
Originally posted by David
The MM apparatus was resting in the earth?s local ether.


Yes, that is another way of saying the same thing. But either way the MM experiment gives no evidence whatever of what happens to light in the extended rest frame of the observer far away from the observer and the Earth's local environment. Which is the idea on which SR is built.

Yes, the Earth has a local 'ether' in the form of the dielectric property of matter.
 
  • #44
Originally posted by meddyn
Don't want to get in the middle of this one but could you please give a reference on this?

Tks.

I asked you to look it up. Do you not know how to use a search engine? Or maybe you want someone else to do your work for you.
 
  • #45
Tha manner of that statement shows, beyond any shadow of doubt, that you don't have a clue.
Duh.
Are you trying to be contrary or do you really not understand ordinary english?
I asked you to look it up. Do you not know how to use a search engine? Or maybe you want someone else to do your work for you.

Nudnik - This attitude is not welcome here. Discuss/debate ideas, don't flame.
 
  • #46
You won't have to worry about it anymore.

{:>)]
 
  • #47
Originally posted by theurinal
Firstly, just a high to everyone, (first post, aye).

Now, everyone has been saying that FTL Travel (Faster than Light) and even the speed of light is impossible. (dammit... ) than how is it that light can go at the speed of light.

Now, for some touching back on the SOL theory. As you approach the SOL time gets slower and the energy needed for the speed gets higher. AT the SOL energy is infinite and time is held. (e.g 12:00 forever: never even hitting 1 ms later)

Now, if the energy required is infinite than how can Light itself go that fast.

Is the secret hidden in Light??!


Now, everyone has been saying that FTL Travel is the speed of light.
 
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  • #49
Originally posted by russ_watters
The "vacuum" of space is not empty either.

Exactly!

The importance of 'Scale' cannot be ignored.
 
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  • #50
Mans clumsy attempt at creating a genuine 2-Dimensional Flat Space from a 3-Dimensional spacetime (matter).
(how can I quote with the original poster as reference ?)

Holy Poly! Do you know what scientist mean with a flat space ? It is independent of the dimensions! A 4 dimensional space can be as flat as a 1- dimensional.
 
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