<<In 1 Billion years, there won't be much life left on Earth because the water will be gone.

"Uh...where were you planning to hide all that water? "

Who cares about the water? In a billion years of time, you would have about 10 impacts roughly the size the one that wiped out the dinosaurs, and good chance of a much bigger rock impacting. And there would other events like nearby supernovas and other stuff. Anything beyond a thousand years isn't worth considering- if we aren't spacefaring and doing all kinds of unimaginable things by then, we are failure and are doomed as any kind of an intelligent species.