The discovery that the universe is still expanding has lead three astrophysicists to share this year’s Nobel Prize in Physics award.
Formally, it was understood that they universe was decelerating in its expansion. That was the notion that many scientists were expected to observe, including astrophysicists Saul Perlmutter, 52, of the University of California, Berkeley, Brian Schmidt, 44, of Australian National University, and Adam Reiss, 41, of The John Hopkins University, when they began to study distant exploding stars named supernovae in the late 1990’s. However, what they discovered was not that the expansion of the universe was slowing down, but in fact it was accelerating due to a source of energy that scientists know very little about called “dark energy.”< /span>
“ We anticipated that gravity had slowed the rate of expansion over time. But that’s not what we found,” explained Riess.
For almost one hundred years, scientists have held firmly to the belief that the universe was created over 14 billion years ago. It was the simultaneous work of early astrophysicists like Albert Einstein and Edwin Hubble that lead to the conclusion that every galaxy observable within the known universe was moving away from a central point. According to their observations, this point represented the starting start of all that is known in the universe during a massive explosion more commonly known as the Big Bang.
At the time of the discovery by the two teams involved — one lead by Perlmutter, the other by both Reiss and Schmidt, astronomers knew that the universe was expanding, but the question remained as to whether it would expand forever, or if it would eventually seize from expanding and eventually collapse back into itself.
The initial results found in 1997 indicated that the universe was not slowing down. In fact it was speeding up, contrary to all cosmological theories, puzzling Perlmutter’s team.
“ The chain of analysis was so long that at first we were reluctant to believe our result,” Perlmutter said. “But the more we analyzed it, the more it wouldn’t go away.
The discovery that the expansion is accelerating was astounding and overturned prevailing theories. The accelerating expansion means that the universe could expand forever until it is cold and dark. The teams’ discovery led to speculation that there is a “dark energy” that is pushing the universe apart. Though dark energy theoretically makes up over 70 percent of the matter and energy of the universe, astronomers have so failed to discover the nature of the odd, repelling force.
Recently, Perlmutter has been working with NASA and the U.S. Department of Energy to build and launch the first space-based observatory designed specifically to understand the nature of dark energy. A dark-energy mission was named the top telescope-building priority in an August 2010 report from a blue-ribbon committee of the National Academy of Sciences.
Research and investigation will continue to pursue dark energy, “ the biggest challenge in cosmology and physics,” said Riess in a release from the Johns Hopkins Institute.
