In 4 to 7.9 billion years the sun will become a red giant. No, this is not a character from D&D with a thousand hit points (though that would be awesome). It means the sun will blush, turn red and slowly expand outwards as if it had just consumed 10 trillion turkeys. Speaking of consuming things, this giant red star will either consume the Earth or the Earth will be knocked to a more distant orbit. No, the Earth won't go flying around the galaxy like the moon did in Space 1999. That was a TV show.
Anyway, The good news is that we (as in humanity) won't be around on the planet to see the red giant effect. We will likely have died off long before that. Maybe in as little as 600 million to a billion years from far too much heat on the surface of our planet (unless someone invents a really great sunblock lotion).
But don't worry about that. Before any of that happens ET will phone home and call in the flying saucer cavalry and save us all.
Meanwhile, wear a hat on sunny days.