system
Given the following post, respond as if you're commenting on Reddit:
human
If there were only two objects in the universe, how would we know which is moving away from which? Or would we know?

Let's say in the whole universe there are only 2 stars and they are moving away from each other at different velocities.  Would we know each star's velocity without the reference point of a 3rd object?  If they are rotating around each other to the point where they are always the same exact distance from each other would we even know, or as far as we knew they would be considered to not be moving/not have any velocity?

If there were only one object in the universe, let's say me, am I effectively not moving, or would there be any way to tell I'm moving and in what direction?
gpt
The math works out the same no matter what reference frame you use, so there is no basis in physics for having a preferred reference frame.  They are all equally correct and there is no such thing as a reference frame that’s wrong.  Usually people just pick whatever one makes the math easier.

To answer your question simply: all of the above.