I'm quite curious to know about this question. I don't really fully understand how inertia works so I couldn't quite put this one together in my head.

As far as I know, if you are moving in empty space, you need a reference point if you want to determine how fast you are going. If you set the reference to something moving exactly with you then your speed is 0, right?

So, imagine you are standing on an infinite hockey rink, but the surface is so perfect it has 0 friction. (Also, there is no air I guess, or any landmarks you could use for reference). Would it be possible to perform some experiment to determine if you are moving or stationary relative to the surface? (Without damaging the surface of course, no creating landmarks) If the surface had a constant and even gravity would that make a difference (i.e. could you change direction and observe different amounts of inertia depending on how fast you were going?)

Or is this situation otherwise identical to drifting in empty space with no reference points?