Humans don’t know much about the universe, but we do know that most of the gravity holding it together—around 85 percent of it—comes from something we can’t see or touch called dark matter. And some other force we can’t see or touch, called dark energy, is simultaneously causing the universe to expand, at an…
There's overwhelming evidence that the universe is accelerating. This means that the future is going to be a relatively lonely place, with galaxies getting ever further from one another, and no hope (if there ever was any) of traveling between them. But could the accelerating universe be even more grim than that?
The universe is about 14 billion years old, but the most distant galaxies are much further than 14 billion light years. How can that be? In this week's "Ask a Physicist," we'll find out.