Rest frame of a photon

  • Thread starter D H
  • Start date

D H

Staff Emeritus
Science Advisor
Insights Author
15,329
681
I've read that in relativity the concept of the rest frame of a photon doesn't make sense. Why is that?

A rest frame of some object is a reference frame in which the object's velocity is zero. One of the key axioms of special relativity is that light moves at c in all reference frames. The rest frame of a photon would require the photon to be at rest (velocity=0) and moving at c (velocity=299792458 m/s). That of course is contradictory. In other words, the concept doesn't make sense.


The following forum members have contributed to this FAQ:
D H
Dale
Fredrik
Pallen
 
Last edited by a moderator:
28,288
4,639
One thing to add to this is a brief comment that while it is not possible to have a reference frame (tetrad) where light is at rest, it is possible to have a non-inertial coordinate system where some light rays have constant coordinates. Light cone coordinates are one such example. This is one place where it is important to understand the subtle distinction between reference frames (tetrads) and coordinate systems.
 
Last edited:

Want to reply to this thread?

"Rest frame of a photon" You must log in or register to reply here.

Related Threads for: Rest frame of a photon

  • Posted
Replies
16
Views
3K
  • Posted
Replies
5
Views
420
  • Posted
Replies
13
Views
2K
Replies
6
Views
482
Replies
19
Views
691
  • Posted
2
Replies
25
Views
6K
Replies
60
Views
6K
  • Posted
Replies
2
Views
3K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top