- #1

Ookke

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Let's imagine a rocket orbiting the earth. The rocket could be any real rocket with moderate speed, so that relativistic effects are not significant, and also rocket does not experice notable centrifugal or other acceleration (so the rockets reference frame would appear almost inertial).

A photon orbits Earth with long enough radius so that its angular velocity matches the rockets angular velocity (see image if necessary). At any time, from rockets reference frame the photon is at constant distance directly on the side. Should we conclude that the photon is stationary when looked from rocket's frame? If yes, how the photon can exist in rocket's frame at all, having no speed (no kinetic energy) or rest mass? If no, i.e. the photon is not stationary but moves, how it actually moves relative to rocket?

I know the rocket is not strictly an inertial observer, but it's "almost" so. And in any case, the rocket is an observer (inertial or not) and the existence of a photon doesn't sound like a frame-dependent thing. I'm sure that there is a solution to this, but nothing that I can see right now. Thanks.

A photon orbits Earth with long enough radius so that its angular velocity matches the rockets angular velocity (see image if necessary). At any time, from rockets reference frame the photon is at constant distance directly on the side. Should we conclude that the photon is stationary when looked from rocket's frame? If yes, how the photon can exist in rocket's frame at all, having no speed (no kinetic energy) or rest mass? If no, i.e. the photon is not stationary but moves, how it actually moves relative to rocket?

I know the rocket is not strictly an inertial observer, but it's "almost" so. And in any case, the rocket is an observer (inertial or not) and the existence of a photon doesn't sound like a frame-dependent thing. I'm sure that there is a solution to this, but nothing that I can see right now. Thanks.