Berkeley Lab competes for 'dark energy' probe

0 Comments | Oakland Tribune, Sep 6, 2007 | by Betsy Mason

Lawrence Berkeley National Laboratory is a step closer to uncovering the nature of the mysterious dark energy that makes up about three-quarters of the universe.

On Wednesday the National Research Council recommended that NASA move forward with the Joint Dark Energy Mission as the first of its Beyond Einstein cosmology missions.

One of three competing projects in the JDEM is Berkeley Lab's SuperNova/Acceleration Probe.

If chosen, SNAP could get the green light for as much as

$1 billion worth of funding beginning in 2009, with a launch in 2014 or 2015. The Department of Energy will fund about half of the project, and NASA would pick up the rest of the tab, pending approval of the NRC recommendation.

"We're delighted that they felt so strongly about JDEM and the investigation of dark energy," said Berkeley Lab physicist Michael Levy, co-leader of the SNAP project.

NASA asked the NRC to assess proposed projects in five mission areas: black holes, dark energy, gravitational radiation, the inflation of the early universe, and testing Einstein's gravitational theory.

Only one project can go forward initially, due to budget constraints. After a yearlong study, the dark energy mission came out on top as the best combination of potential scientific impact and technical readiness.

If SNAP is chosen, an international team led by Berkeley Lab will prepare to launch a telescope and camera into space that can capture images of distant exploding stars called supernovae. The probe will also make a high-resolution map that will use tiny distortions of the light from distant galaxies that will begin to reveal the uneven distribution of matter, a technique known as weak lensing. This will help determine which ideas about the nature of dark energy are real possibilities, and which don't work.

"We believe that most of the universe is made out of this stuff and it seems like we should know what it is," Saul Perlmutter, Berkeley Lab physicist and co-leader of the SNAP project, said in a teleconference from England, where he is accepting the 2007 Gruber Cosmology Prize for his role in the discovery of dark energy.

Perlmutter led one of two teams that in 1998 discovered that the expansion of the universe is accelerating by measuring changes in the light from relatively nearby supernovae. The reason for this unexpected acceleration is some sort of force that overwhelms the universe's gravitational pull. Because it is so mysterious, the force was dubbed dark energy.

Betsy Mason covers science and the national laboratories. Reach her at 925-952-5026 or bmason@bayareanewsgroup.com.