Is theory of relativity really relative ?

Click For Summary

Discussion Overview

The discussion revolves around the implications and interpretations of the theory of relativity, particularly concerning the concept of reference frames and the speed of light. Participants explore the idea of what it means to consider light as a frame of reference, the contradictions that arise from such considerations, and the implications for understanding the behavior of light and other particles in relativistic contexts.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants question the validity of asking what speed light travels relative to a hypothetical observer moving at the speed of light, suggesting that such a scenario is inherently contradictory.
  • Others argue that no inertial reference frame exists where a photon is at rest, making the question of light's frame of reference meaningless within the context of relativity theory.
  • There are claims regarding neutrinos potentially traveling faster than light, which some participants use to challenge the validity of Einstein's theory, although this is met with counterarguments pointing out measurement errors in those claims.
  • Participants discuss a thought experiment involving two stationary physicists and a third physicist moving at light speed, debating the implications of whether the laser pulse reaches the second physicist from the perspective of the third.
  • One participant attempts to clarify the thought experiment but is met with confusion from others, highlighting the complexity of the argument and the need for clearer communication.
  • Another participant introduces the idea that a rest frame for a photon would imply contradictions regarding energy and momentum, suggesting that such a frame cannot exist.
  • Some participants express frustration with the clarity of others' arguments, indicating a need for better articulation of ideas.

Areas of Agreement / Disagreement

Participants generally disagree on the feasibility of using light as a reference frame, with multiple competing views on the implications of relativity and the nature of light. The discussion remains unresolved, with no consensus reached on the validity of the claims made.

Contextual Notes

Limitations include the dependence on definitions of reference frames and the unresolved nature of claims regarding neutrinos and their speeds. The discussion also reflects varying levels of understanding among participants, which affects the clarity of the arguments presented.

Wicked Wildie
Messages
3
Reaction score
0
Einstein made the theory based on Maxwell saying that electromagnetic waves travel with same speed from the view of all inertial & non - inertial frame. Then with what speed relative to a person sitting on light does light travel ?
 
Physics news on Phys.org
How does one sit on light?

In fact no person can travel at the speed of light, so the question itself is a contradiction. :)
 
Wicked Wildie said:
a person sitting on light

Such a person is impossible.

Even leaving out material people or objects, there is no inertial reference frame in which a light beam/ray/photon is at rest, so it's meaningless (in the context of relativity theory) to ask what things "look like" from that point of view.
 
I'm nt saying to sit on it.. Jst have light as your frame of reference...
 
and when u say nothing can travel at speed of light, my dear friend, we've neutrinos having speed greater than that of light. einstein's theory is on the verge of being proved wrong
 
Matterwave said:
How does one sit on light?

In fact no person can travel at the speed of light, so the question itself is a contradiction. :)

You shouldn't be in theoretical physics if you make statements like that.
 
Wicked Wildie said:
and when u say nothing can travel at speed of light, my dear friend, we've neutrinos having speed greater than that of light. einstein's theory is on the verge of being proved wrong

You don't follow scientific news. That was a technical problem leading to more errors in the measurements and neutrinos weren't moving faster than light.

TheScienceOrca said:
You shouldn't be in theoretical physics if you make statements like that.

You mean theoretical physics is where you can say anything contradictory?!
Imagine two physicists at rest relative to each other standing far from each other. One of them shines a laser at the other one which the other one surely receives. Now imagine another physicist passing by at the speed of light in the opposite direction to the direction of motion of the laser pulse. According to him, the pulse never reaches the other guy. But the fact that the pulse reaches the other guy or not shouldn't depend on the frame of reference. So no one can go at the speed of light(or faster!).

About a photon's frame, according to one of the SR's postulates, light moves with speed c in vacuum relative to any inertial frame. Now if we assume that we can associate to light, an inertial frame, a frame which light is at rest with respect to it, the postulate says that light should go at speed c relative to it. CONTRADICTION!
 
Last edited:
Shyan said:
Imagine two physicists at rest relative to each other standing far from each other. One of them shines a laser at the other one which the other one surely receives. Now imagine another physicist passing by at the speed of light in the opposite direction to the direction of motion of the laser pulse. According to him, the pulse never reaches the other guy. But the fact that the pulse reaches the other guy or not shouldn't depend on the frame of reference. So no one can go at the speed of light(or faster!).CONTRADICTION!

This sounds like it might be a useful argument. Unfortunately I can't make any sense of it, can you confirm that you have said exactly what you mean?
 
m4r35n357 said:
This sounds like it might be a useful argument. Unfortunately I can't make any sense of it, can you confirm that you have said exactly what you mean?

Yes.
Where is the first place that you feel its hazy? I mean, as you read, there should be somewhere that you start to feel you don't understand it. Where is that place?
 
  • #10
Shyan said:
Yes.
Where is the first place that you feel its hazy? I mean, as you read, there should be somewhere that you start to feel you don't understand it. Where is that place?

Sort of the third sentence (passing by whom? both, I suppose), but definitely the fourth (there are three guys, who is the "other" guy?). By the fifth sentence I am just reading words without understanding them.

Could you possibly draw a diagram?
 
  • #12
m4r35n357 said:
Sort of the third sentence (passing by whom? both, I suppose), but definitely the fourth (there are three guys, who is the "other" guy?). By the fifth sentence I am just reading words without understanding them.

Could you possibly draw a diagram?

Oh...right...I should explain more clearly.
There are two stationary physicists S1 and S2 located far from each other. And there is a third physicist moving at the speed of light in a straight line connecting S2 and S1, from S2 to S1, who we call M.
S1 shines a laser at S2 which, by experience, we know S2 receives.
But in the frame of M, the laser pulse doesn't reach S2.
But the fact that the laser pulse reaches S2 or not shouldn't depend on the frame of reference.
 
Last edited:
  • #13
m4r35n357 said:
... I am just reading words without understanding them.

Yeah, I believe so. I was trying to understand what he said above but I couldn't. There were just words put together in a meaningless way. @Shyan please try to write in proper English.
 
  • #14
Shyan said:
Oh...right...I should explain more clearly.
There are two stationary physicists S1 and S2 located far from each other. And there is a third physicist moving at the speed of light in a straight line connecting S2 and S1, from S2 to S1, who we call M.
S1 shines a laser at S2 which, by experience, we know S2 receives.
But in the frame of M, the laser pulse doesn't reach S2.
But the fact that the laser pulse reaches S2 or not shouldn't depend on the frame of reference.

OK, thanks for clarifying, I understand the layout now. I do have another question though; how does M detect whether S2 receives the pulse?
 
  • #15
I think the easiest way to see that rest frame is impossible, is by looking at the photon that satisfies E=pc or m=0,
Now a rest frame for the photon (p=0) would also imply E=0. So you have a massless, no-energy, no-momentum particle? That's nothingness.
 
Last edited:
  • #16
Wicked Wildie said:
I'm nt saying to sit on it.. Jst have light as your frame of reference...
There's no inertial frame of reference that's comoving with light, in special relativity or general relativity (see the FAQ that Nugatory linked to), so what theory would you like us to use to answer your question?

Wicked Wildie said:
and when u say nothing can travel at speed of light, my dear friend, we've neutrinos having speed greater than that of light. einstein's theory is on the verge of being proved wrong
If you keep making claims like that, you will find that we have very little tolerance for them in this forum.
 
  • #17
As for M, that's not even possible... M is causally disconnected from S2... no signal sent from S2's worldlines can reach M...no?
 
Last edited:
  • #18
Yeah, Now that I think, I myself doubt that argument. But I read it in a book which I don't remember what book was it right now and I can't find it.
 

Similar threads

High School Is time an illusion?
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Is Simultaneity Absolute or Relative in the Theory of Relativity?
  • · Replies 38 ·
2
Replies
38
Views
4K
Undergrad GR as Gauge Theory
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad The Einstein Clock aka Light Clock
  • · Replies 34 ·
2
Replies
34
Views
4K
Undergrad SR textbooks discussing accelerated reference frames without delving into GR
  • · Replies 36 ·
2
Replies
36
Views
5K
Undergrad What causes time dilation and length contraction
  • · Replies 10 ·
Replies
10
Views
2K
Undergrad Special Theory of Relativity & Conservation of Mass
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Understanding Einstein's second postulate of special relativity
  • · Replies 57 ·
2
Replies
57
Views
8K
High School Am I understanding the concept of proper frame of reference?
  • · Replies 33 ·
2
Replies
33
Views
3K
Undergrad Does the metric in general relativity depend only on position because of the equivalence principle?
  • · Replies 16 ·
Replies
16
Views
2K