We’ve known for a long time that the universe is expanding, but there have been different theories as to the long-term future of the universe.
One, that eventually all the gravity from the billions upon billions of galaxies will slow the universe’s expansion, and then begin to pull it back into itself. This could even be part of a cycle where the universe expands from one Big Bang, then contracts, then expands again in another Big Bang, and so on.
Another theory that never got much credence is that the universe would expand until eventually it would hit some kind of a limit, or wall, and stop expanding. And that’s just, well, silly. Yup.
But now, thanks to the 2011 Nobel Prize in Physics winners Saul Perlmutter, Brian Schmidt, and Adam Riess, we can rest easy knowing that in the years to come, the universe will continue expanding into an ever lonelier, darker, and colder vast of emptiness and silence, until the end of time. This is because of dark energy, which is causing the expansion of the universe to accelerate. As always, minutephysics explains it simply and clearly…