# Photons relativity and US

## Main Question or Discussion Point

Hi! First sorry my little bad english :-)
My question is... A photon leaves the surface of the sun. It needs approx 8 mins to reach the Earth. Or we can say - in the notion of relativity - that the Earth needs 8 mins to reach the photon. BUT! Photons moving at c. And if we solve the Lorentz equation we get that in the viewpoint of photons there is no distance between two points in space. So the pov of photon the Earth just... get there with no time. But in our point of view... Besically we can say the photon IS moving toward us and we DONT move toward the photon. So...where is the relativity of moving? :-)

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Matterwave
Gold Member
There is no inertial reference frame in which the photon is at rest. As such, the photon has no rest frame.

Nugatory
Mentor
The light signal has no "point of view"; the speed of light is equal to $c$ in all inertial frames and therefore there is no inertial frame in which a light signal is at rest. The derivation of the Lorentz transforms starts with the assumption that both frames are inertial and therefore the transforms cannot be applied in this situation; if you try it, you'll just end up with garbage-in-garbage-out bogus results.

There is a FAQ on this topic: https://www.physicsforums.com/threads/rest-frame-of-a-photon.511170/

(You may also notice that I'm saying "light signal" instead of "photon". A photon isn't what you think it is; this doesn't matter here, but in some other thought experiments it will).

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