I don't think planet "Earth" itself will end anytime soon...Unless, we end it ourselves...Or we poison it to the degree that WE cannot live on it.
I personally think that, There's a cycle...We'll all eventually die out once we've finished poisoning the place, or, the rest of us will go and "Discover" some other planets, and we'll all move over there...
Millions of years later, someone says "Wow, Look what I've discovered"....And we'll all end up back here. By then, there won't be any trace of (Our) Existance...I believe the planet just "Cleans" itself, or, species just evolve to live in the conditions that we have now...
Might sound far fetched - But how can we say the earth is "Millions of years old and a "Big Bang" made it all" - Now, that, is far fetched...