Not necessarily. Just like space is growing without the need for an objective outside frame of reference, it could be rotating - the rotation is just relative to itself.

[–] SaltSong@startrek.website 1 points 1 week ago (1 children)

I don't think something can rotate relevant to itself. If all of reality was the earth, and nothing else, how can you tell if it's spinning or not?

Please use small words if you try to answer this. I know a decent bit of applied physics, but once it turns to pure math, my head starts to swim.

[–] FooBarrington@lemmy.world 1 points 1 week ago

Stuff could move around differently. Rotations have many effects, e.g. rotation curves (the closer you are to the center of the rotation, the faster you go). We could still figure out that the earth is rotating by measuring the effects a rotation has.