Astrophysicists Share Nobel -- and a Mystery

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A trio of relatively young astronomers won the prestigious Nobel Prize for Physics today, not for solving a problem, but for making an observation: Our universe is expanding faster now than it did in the past.

Whoever figures out why this is happening likely will get a Nobel of his or her own — plus the one just awarded to 41-year-old astronomer Adam Riess, with Johns Hopkins University and the Space Telescope Science Institute in Baltimore.

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"It's a very juicy problem," Riess told reporters on a conference call. "It's hard and you'll win a Nobel Prize if you figure it out. In fact, I’ll give you mine."

The leading theory for the universe's accelerating girth is an anti-gravity force called dark energy, but that's pure speculation at this point. New observatories providing deep and wide views of the universe will help, but what is really needed to resolve the puzzle is a new conceptual framework.

"At best we will get some clues about the nature of dark energy (from observations), but we won’t really resolve it until some brilliant person, the next Einstein-like person, is able to get the idea of what's going on and we can test that idea," Riess told Discovery News.

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Image: The 2011 Nobel Prize in Physics winners: Riess, Perlmutter and Schmidt.

Riess shares the 2011 Nobel Prize in physics with University of California, Berkeley, astrophysicist Saul Perlmutter, who headed a rival team looking at the same phenomena, and with American-Australian Brian Schmidt, 44, a professor of astronomy at the Australian National University, who worked with both teams.

"It’s going to be a huge job for us to get to the bottom of what's going on here," Perlmutter, who turned 52 last week, tells Discovery News.

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Evidence, which is still being collected, comes from measuring the brightness of exploding stars called supernovae, which emit roughly the same amount of light wherever and whenever they're found. If you know you're looking at a 100-watt lightbulb, for example, you can tell how far away it is based on how much of the light you can see. From their observations of supernovae, the scientists were able to determine that the universe is expanding at a faster rate now than it did in its younger days.

Perlmutter's team began by observing the rate of expansion of the distant universe and comparing it with today's acceleration. Riess' team worked from the present day, back to the past. During presentations of research papers at science conferences, the two scientists came to realize that their teams were both making the same bizarre findings, so while there was competition, there also was comfort that the weirdness was not an error in instrument, technique or judgment.

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The observations were, and continue to be, a young person's game, with data collections from a myriad of telescopes and teams over five time zones.

"The fact that these two teams were full of young, enthusiastic people is a lot of what made it all happen," Perlmutter said.

Image (top): Supernova 1994D, the bright spot in the lower left of this image, is one of the "standard candles" of celestial objects astronomers use to scope the parameters of the universe. It lies on the outskirts of the disk galaxy NGC 4526. Credit: High-Z Supernova Search Team/HST/NASA.