

If the crystalline structure of water did not expand from it’s liquid phase (thus lowering it’s density) when it freezes, then ice would not float. Ice would sink trapping everything below it. It’s theorized that this little fact means life likely couldn’t exist if ice didn’t behave this way.
Nope, not possible. The solar system itself is moving as is the galaxy… it’s useful to think of Earth’s orbit as spiraling around the sun in the direction our star is traveling. So 1 orbit later we have not come to the same location.