Dark Discovery 
RIESS: We were all looking for the degree to which the universe was decelerating, which would reveal the mass content of the universe, and its ultimate fate. We were measuring supernovae, which are exploding stars, which are good tools for measuring changes in the expansion rate of the universe.
Adam Riess was a leader of one of two teams of astronomers that were trying to find out how quickly the expansion of the universe was slowing down. But as they analyzed their findings, both teams were in for a shock. They found that instead of expanding slower, the universe was actually beginning to expand faster. Their discovery was called “dark energy.”
The discovery, in the late 1990s, earned the two teams a share of this year’s Nobel Prize for physics, which will be awarded today.
It turns out that dark energy accounts for more than 70 percent of all the energy and matter in the universe. But the leader of the other team and another of the Nobel Prize winners, Saul Perlmutter, explains that its nature is still a mystery:
PERLMUTTER: We have many, many more alternative theories that have been proposed, but none of the theorists who proposed them would say “this is the right one,” they’re just saying that they’re just trying to expand the range of options. So they really look to us experimentalists, observers, to see what can we do to help narrow in on some range of answers.
Many scientists are trying to provide those answers, and reveal the true nature of dark energy — discoveries that could lead to yet more Nobel prizes.
We’ll talk about a Nobel for another kind of mysterious energy tomorrow.
Script by Damond Benningfield, Copyright 2011