Originally posted on sciy.org by Ron Anastasia on Tue 17 Jul 2007 10:05 AM PDT  

Hopkins scientist wins top cosmology prize

Adam Riess, the Johns Hopkins University astrophysicist who discovered that the universe is flying apart at an accelerating rate in response to a still-mysterious force dubbed "dark energy," has won yet another top prize for his discovery.

The Peter Gruber Foundation announced today that Riess and his co-discoverers will share the $500,000 Peter Gruber Cosmology Prize for 2007 with a competing team of scientists.

The unrestricted cash award and gold medal are given annually to scientists for "theoretical, analytical, or conceptual discoveries leading to fundamental advances in the field," according to the foundation's Web site.

The prize is described by Hopkins as "one of the most prestigious prizes in cosmology," and by PhysicsWeb as "the world's only award for cosmology."

Whichever way you look at it, "It's quite a nice honor," said Riess, 37. "I'm very happy about it."

Cosmology is the study of the origins and evolution of the universe as a whole, compared to astronomy, which concentrates on celestial objects such as planets, stars and galaxies.

Riess might have been even happier last year, when he and two co-discoverers shared the $1 million Shaw Prize, an international award for groundbreaking discoveries in astronomy, mathematics, life sciences and medicine.

"The Shaw prize was far more lucrative," said Riess, who was lead author of the first dark energy paper at the age of 28.

He split the Shaw Prize three ways, with Brian P. Schmidt, of the Australian National University, and Saul Perlmutter, of the University of California Berkeley.

Schmidt led the High-z Supernova Search team. Riess was a member and first author of the High-z group's seminal 1998 paper in the journal Science. Perlmutter led the competing Supernova Cosmology Project, which shared in the discovery, but published second, in 1999. The two papers are now among the most cited of the last decade.

This time, the two groups have agreed to split the award in half, with all 51 team members on the two teams receiving shares.

But then, Riess stressed, "It's not about the money. ... It gets people focused on the wrong thing."

At the time of the original discovery, Riess was a young astronomer at Berkeley, analyzing the light from a collection of exploding stars called Type 1a supernovae. He was trying to calculate their distance from Earth and the speed at which they were receding with the expansion of the universe.

To his puzzlement, it looked as though the more distant supernovae were moving away more slowly than those that were nearer to Earth in both space and time.

The implication was that the expansion of the universe has been accelerating for billions of years. And that flew in the face of cosmologists' assumptions at the time -- that gravity ought to be gradually slowing the expansion.

Something -- it came to be called "dark energy," but scientists still don't know precisely what it is -- is repelling all the matter in the universe. It was an idea first articulated by Albert Einstein, who later rejected it as his "biggest blunder."

Riess thought at first that there must be a glitch in his own math. But the more his team members checked and rechecked, the more they became convinced the acceleration was real.

"When I was writing that paper 10 years ago, I had no idea this would remain true. Most things in science that are really surprising are wrong," he said.

Once he'd published, he thought someone else would find an error in his work. No one did. "If anything, the evidence has gotten a lot stronger," he said.

"I think of this as the end of the beginning for cosmology," Riess said. "Now, for the first time, we have plumbed the depths of the universe and identified all the first constituents." Now, scientists believe dark energy constitutes 70 percent of all the matter and energy in the universe. But they still have no idea what it is or how it works.

"Everybody has been working on follow-up studies. What is this stuff and what is its nature?" Riess said. "It's a huge industry now. Many people think of it as one of the two hottest things" in physics and astronomy.

The second would be the search for planets -- and ultimately habitable, or inhabited planets -- around distant stars.

Riess has said he once worried aloud to his mother that he'd peaked too early in his career. But "that was the concern of a 29-year-old," he said, laughing. "I've come to realize over time how rare these discoveries are, and I've learned to appreciate it more. ... You're lucky to get such a mystery in your time to work on."

In 1999, Riess moved to the Space Telescope Science Institute in Baltimore to continue his work, using the Hubble Space Telescope. He and his colleagues began publishing more results, adding evidence to support their discovery.

In 2006 he joined the faculty at Hopkins, where he is now a professor in the Henry A. Rowland Department of Physics and Astronomy.

This is not the first Gruber Cosmology Prize for a Hopkins scientist, nor for a Marylander.

Last year's Gruber was presented to John Mather, an astrophysicist at the Goddard Space Flight Center, in Greenbelt. He led NASA's Cosmic Background Explorer (COBE) team, whose discoveries earned Mather and Berkeley's George F. Smoot the 2006 Nobel Prize in physics.

Another member of NASA's COBE team who shared the 2006 Gruber award was Hopkins astrophysicist Charles L. Bennett.

The COBE orbiting observatory measured remnants of the microwave and infrared radiation released with the Big Bang that cosmologists believe marked the beginning of all space, matter and time.

Slight variations in that radiation across the sky, the COBE team discovered, marked differences in density, called "anisotropies," that -- with gravity -- gave rise, over billions of years, to the galaxies, stars, planets and everything on them.


frank.roylance@baltsun.com

---

Attachment: