It's said the earth is approaching the sun. Can we push it away little by little?
Although we can emit rocket towards the sun, but it's too expensive to make a rocket:
So I think maybe we can recycle the rocket, at first, the rocket is send out with a very fast speed, so give back a big force to the earth. And then, we let the rocket slowly comes back to the earth, and re-send it again:
Well, this solution sounds a little inefficient. Still I don't know if it works. Better ideas?
Umm.. It seems the earth is leaving the sun. That's ok. Then, the question is how can we push the earth towards the sun, i.e., correct the orbit by human force? Even if the sun turns into a red giant someday, we may finally find a way to put the earth at a safe position far enough from heat.