Why the proper time of photon is zero?

Question

I'm currently taking classes on General Relativity, and whilst working on Geodesis equation:

Find out that for mass particle q is equivalent to proper time but in case of photon the proper time of photon is zero. Could you please explain why? (For note, surprisingly but i didn't have proper Special relativity lessons)

Does this answer your question? Proper time for a light particle — Eletie, May 19 '22 at 10:42

score 0 · Answer 1 · answered May 19 '22 at 10:41

0

Because for a massless particle $ds^2=0$.

answered May 19 '22 at 10:41

Oбжорoв

3,098

While this is correct, I don't think it will be terribly useful to the OP without more details. – Michael Seifert May 19 '22 at 13:50
@MichaelSeifert it should be useful for the OP as he is taking GR classes. – Oбжорoв May 19 '22 at 18:33
They also say that their special relativity background is weak, though. – Michael Seifert May 19 '22 at 18:45
I think this answer: https://physics.stackexchange.com/a/709601/281096 although given to other question would be more helpful. – JanG May 20 '22 at 10:35

Why the proper time of photon is zero?

1 Answers1