How does a photon view the universe?

Click For Summary

Discussion Overview

The discussion revolves around the conceptual understanding of photons and their properties, particularly in relation to special relativity (SR). Participants explore the implications of time dilation and length contraction on photons, the validity of describing photons in a "frozen" state, and the nature of entanglement. The scope includes theoretical interpretations and challenges to established notions within physics.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that photons are defined as time-dependent oscillations of electric and magnetic fields, raising questions about the validity of this description if photons are considered to experience no time or distance.
  • There is a suggestion that the concept of a photon may be inconsistent when discussing "frozen" states, particularly in relation to absorption and emission processes involving different wavelengths, such as radio waves.
  • Concerns are raised about the application of special relativity to photons, with some arguing that if photons exist at the speed of light, they should not have a defined existence due to infinite contraction and dilation.
  • One participant questions how professors can assert the well-defined nature of infinite contraction and dilation in relation to photons, noting conflicting views among educators on the applicability of SR to light.
  • There is a discussion about entanglement, with a participant proposing that if photons do not experience distance or time, this could imply a shared identity in entangled states.
  • Another participant argues that discussions about the perspective of light are fundamentally self-contradictory within the framework of relativity, reinforcing skepticism about the validity of such inquiries.

Areas of Agreement / Disagreement

Participants express disagreement on the interpretation of photons in relation to special relativity, with some supporting the idea that the perspective of light is problematic, while others question the validity of this stance. The discussion remains unresolved with multiple competing views presented.

Contextual Notes

Limitations include the undefined nature of certain mathematical expressions in the context of SR, as well as the challenges in reconciling the behavior of light with established physical theories. The discussion highlights the complexity of applying relativistic principles to entities moving at the speed of light.

Al X
Messages
7
Reaction score
0
This question has been bugging me quite some time now. I'll start presenting my background for the problem:

Fact:
Photons are time-dependent oscillations of electric and magnetic fields as described by Maxwell's equations.

Now, I've heard a lot of people, including professors saying that a photon experiences no time and no distance due to time dilation and length contraction. Also, I've heard a professor say that if you could travel alongside the photon (this seems weird per the postulates of SR), you would see frozen electric and magnetic fields. My questions are:

1. Can we use the word photon about something that's frozen in time? Or is the photon description only valid when we have a time-dependent oscillation.

2. If the answer above is that we can, then I assume it has something to do with photons being a quanta of light. This is especially used when talking about absorption and emission of photons. What about radiowaves that can have a wavelength of several km? Can we speak of an immidiate absorption and emission? Does the photon definition collapse?

3. If we apply SR to the photons, they shouldn't exist. Since the distance between two points are infinitely contracted. Also, on the flipside of this effect, the photon uses an infinitely small time to cross the distance due to time dilation. This seems to me to be in contradiction of us knowing electromagnetic waves exist, and that we can measure a wavelength and frequency.

4. How can a professor say that the infinite contraction and dilation, and frozen fields are well defined? I don't ask this to bash the guy, I just simply don't get it. Especially since another professor I've had is saying this is unsatisfactionary and that SR shouldn't be applied to light in this way.

5. Finally, entangled photons. Now say that it is true that photons don't experience distance, nor time, but we can experience the time and distance they've travelled. Could the entanglement be due to the fact that we're basically manipulating the same photon?

Let's discuss!
 
Physics news on Phys.org
Photons aren't what you're thinking they are, but if we substitute the words "flash of light" for "photon" throughout we'll get through #1-#4.

Basically, any discussion of the point of view of something moving at the speed of light is inconsistent with SR (so you're right to have been dubious). You'll hear this bit about time stopping and lengths contracting to zero a lot in the popular press, but it's basically bogus. We even have a FAQ on this, because it comes up so often.

#5 doesn't work because massive particles which move at speeds less than that of light can also be entangled.
 
  • Like
Likes   Reactions: vanhees71
To answer your question, you need to jump to the reference frame of the photon. What is the corresponding Lorentz transformation?
 
Al X said:
4. How can a professor say that the infinite contraction and dilation, and frozen fields are well defined? I don't ask this to bash the guy, I just simply don't get it. Especially since another professor I've had is saying this is unsatisfactionary and that SR shouldn't be applied to light in this way.

This sums up the issue. The second professor is right. There is nothing in SR about infinite contraction and dilation and there is no frame of reference for a photon.

If you look at the mathematics, then it may be tempting to interpret an undefined quantity (such as ##1/0##) as "infinite". But, mathematically, that is unsound. ##1/0## is undefined.

It's a shame if this question has been bugging you, as it is not really a valid question or valid issue at all.
 
Thanks guys! That helped a lot!
 
One of the postulates of special relativity is that light travels at the same speed in all inertial frames of reference. A frame of reference moving along with a pulse of light would be an inertial frame (in the sense that it is moving at constant speed viewed from another inertial frame). So light would have to be moving at light speed. But it would also have to be stationary because that's what moving along with something means.

That's how fundamental the problem with "the perspective of light" is. The notion is self-contradictory in relativity. You were right to be suspicious.
 
  • Like
Likes   Reactions: PeroK

Similar threads

Undergrad How Does Special Relativity Affect Perceptions of Simultaneity?
  • · Replies 32 ·
2
Replies
32
Views
2K
High School Energy loss of a photon
  • · Replies 1 ·
Replies
1
Views
1K
High School Let me ask a thing about the Speed of Light
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Basic Special Relativity question but the math isn’t working
  • · Replies 17 ·
Replies
17
Views
2K
High School Photon Frequency: How Special Relativity Affects Light
  • · Replies 23 ·
Replies
23
Views
3K
Undergrad Revisiting the Light Clock
  • · Replies 25 ·
Replies
25
Views
1K
High School Challenging the notion of "crossing" a black hole's event horizon
  • · Replies 25 ·
Replies
25
Views
4K
High School Does Spacetime Have Physical Existence?
  • · Replies 58 ·
2
Replies
58
Views
4K
Undergrad What happens to the energy lost by photons in gravity?
  • · Replies 38 ·
2
Replies
38
Views
5K
Undergrad Does a blueshift change the energy of a photon?
  • · Replies 22 ·
Replies
22
Views
3K