What's the future for the Universe?
Well let me tell you the bad news first, the Universe is past its peak; there are more stars dying than are being born so the galaxies are gradually fading. As they do, more black holes are being formed. Those that exist gradually consume more materials, and eventually, we'll end up with a universe of black holes and faint remnants of stars like the sun called "white walls," which are just cold balls of material that are gradually cooling down and that's it. That takes about a billion billion years and then that's it for a really really long time. Steven Hawking becomes important because his greatest contribution to science is the prediction of what's known as Hawking radiation; and this says that black holes gradually dissolve, very very slowly. I won't go into the details but black holes gradually give out light and that uses up energy. The energy has to come from somewhere so the black hole gradually shrinks. So for the next 10 to the 80 years (that's 1 followed by 80 zeroes), the black holes will gradually radiate and disappear into nothing. Now all this time, the universe is expanding; its being accelerated by a mysterious force called dark energy; so these black holes get further and further away from each other; and while they are giving out their light, if you were sitting on one, gradually you will see the universe appear to shrink, because although its expanding, everything else disappears over our horizon, so we're left with just one little black hole that we're sitting on and then gradually the black holes evaporate, and we're left with a sea of radiation that expands forever and ever. The end.
