> For example the gravity between two objects depends on the relative speed between them (since gravity is proportional to energy, not rest mass). Are we calcul

> For example the gravity between two objects depends on the relative speed between them (since gravity is proportional to energy, not rest mass). Are we calculating that for each and every sun orbiting in a galaxy? Disk stars in the Milky Way only have velocities on the order of a few hundred km/s. The relativistic contribution to gravity from such velocity is negligible.