Is the Concept of Zero Length Contraction Possible in Special Relativity?

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Discussion Overview

The discussion centers around the concept of zero length contraction in the context of Special Relativity (SR) and the implications of viewing the universe from the photon's perspective. Participants explore the mathematical formulations of length contraction and time dilation, questioning their applicability to light itself and the nature of speed in relation to light.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants propose that if the velocity of light (c) is considered, then distances contract to zero from the photon's perspective, suggesting that a photon experiences no time or distance.
  • Others argue that while distances may contract, the time taken for a photon to traverse any distance remains finite when viewed from the universe's frame, indicating that c does not need to be infinite.
  • One participant introduces the idea that as velocity approaches c, time dilation leads to an infinite time, resulting in an undefined value for c when calculated as distance over time.
  • Another participant questions whether the equations for length contraction and time dilation apply to light, suggesting they are intended for matter, while others counter that these equations should apply universally to all objects in motion, including photons.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of length contraction and time dilation to light. There is no consensus on whether the equations of SR can be applied to photons or if they yield meaningful results in that context.

Contextual Notes

Participants highlight limitations in understanding the implications of approaching the speed of light, particularly regarding the definitions of time and distance in the photon's frame. The discussion remains open-ended without resolving these complexities.

deda
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In Einstein's SR the velocity of the light (c) is same in every referent frame. Let us for instance assume we don't know its exact value and try to estimate it. The relative distance suffers contractions depending on the velocity of the frame like this:
[tex]L=L_0\sqrt{1-\frac{V^2}{c^2}}[/tex]
where L0 is the rest frame distance; L is the relativ contracted distance; V is the velocity of the frame.
But what if V=c or we have the photon's point of view?
Then every distance contracts to zero meaning that from the very instance of its creation the photon is already every where. This is only possible if c=infinity or the light transmition is instant. The c=infinity can only be result of direct change of charge(the wave nature) or direct change of the mass (the particle nature). If it happens then the changes affect the rest of the universe instantly.

What about it?
 
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Originally posted by deda
In Einstein's SR the velocity of the light (c) is same in every referent frame. Let us for instance assume we don't know its exact value and try to estimate it. The relative distance suffers contractions depending on the velocity of the frame like this:
[tex]L=L_0\sqrt{1-\frac{V^2}{c^2}}[/tex]
where L0 is the rest frame distance; L is the relativ contracted distance; V is the velocity of the frame.
But what if V=c or we have the photon's point of view?
Then every distance contracts to zero meaning that from the very instance of its creation the photon is already every where. This is only possible if c=infinity or the light transmition is instant.

The universe contracts to zero length from the frame of the photon meaning that the photon takes zero time to cross the universe at c. Zero distance divided by any velocity equals zero time, so c need not be infinite.

On the other hand, from the universe's frame, its distance doesn't contract and the photon takes just the amount of time to cross any distance as it would need traveling at 300,000 km/s, so again, c is not infinite.

So from neither frame do you have to consider c as infinite.
 
I think we should not forget that if length contracts the way it does, the time sequence necessary to pass that length delates this way:
[tex]T=\frac{T_0}{\sqrt{1-\frac{V^2}{c^2}}}[/tex]
So the if V -> c then T=infinity.
Now if we would try to calculate c as L/T=dx/dt then c=0/infinity.
This is the worst case of undefined number cause it's neither 0 neither 3E8km/s nor infinity. A totally undefined number.

If it is so in photon's frame then it's so in every frame.
 
correct me if I am wrong but i thought the equations that describe length contraction and time dilation are only for use for matter not for the light itself which already is with c speed.
 
Originally posted by loop quantum gravity
correct me if I am wrong but i thought the equations that describe length contraction and time dilation are only for use for matter not for the light itself which already is with c speed.
It applies to every object in motion.I don't see why a photon would be special.
 

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