Masteria Expansions, Names and the proof for each

Actually, it isn't gravity that keeps us from being left behind in space as the earth rotates... it's momentum.

So if, as Afrobean said, the time traveling matter is affected by forces, then it would continue being affected by its circular momentum around the sun and etc.

Then again, the fact that you're going backward complicates things. If you were standing on a particular brick in Helios Tower, and you rewind back to when Helios was being built, you'd be carried back to wherever that brick came from.