In only about 200 million years it will be way too hot for humans on earth. And in 500 million years from now, the sun will have become so bright and big, our atmosphere will evaporate, the oceans will boil off, and surface dirt will melt into glass. Not even our south Georgia cockroaches will be able to survive that.

Finally, as a red giant star 4 billion years from now, the sun will begin to fuse helium into carbon in its core, which will continue for only 1 billion years before its helium fuel runs low. For a light-weight star like our sun, helium is the last energy source to hold gravity at bay. When finally helium runs low, the sun will give in to gravity and die rather quietly, without disturbing the neighbors.