Sorry for everyone who wants the world to end in ice, it will end in a giant ball of flames.

You see, in approximately five or six billion years, the sun will run out of its current fuel (hydrogen) and switch to its back up fuel (helium). When this happens, it will swell to the size of a red giant and consume all the Inner Planets. Then it will burn for another two to three billion years before IMPLODING (not exploding. Only Supergiants explode into a Supernova and create black holes) and becoming a nebula, then a white drawf, then a black dwarf.

Hey, maybe humans will have colonized Pluto by then. After all, we are already colonizing Mars.