Momentum of a point mass is changed by motion (excepting uniform linear motion) of this point mass. It will show the existence of rest frame.

Two disks are rotating (in outer space ; in non-gravitational field ; horizontally). Rotating speed of one disk is 10 rotations per second and that of the other disk is 20. A body is detached from the edge of disk and is receding along a tangent line (and every tangent line does not rotate relative to space). It will be the same about a photon (emitted from a rotating source).

Why is a pulsar visible as a point (not short line)? It will be caused by aether.