Physics @ Berkeley
Physics in the News
Title: Lab Aims To Shine Light On Dark Energy
Date: 08/10/2006
Publication: Contra Costa Times
Editor: Betsy Mason, 925-847-2158 or
Extended Text:

awrence Berkeley Laboratory is a step closer to unraveling the mystery of dark energy. The lab's vision for a space mission made NASA's short list Wednesday.

The lab is leading an international team of about 140 scientists at 14 different institutions, including UC Berkeley and the Stanford Linear Accelerator Center, to design a space telescope and camera to capture images of distant supernovae.

These exploding stars may give clues to the enigmatic dark energy that makes up more than three quarters of the universe but about which almost nothing is known.

The Berkeley lab has been working on designing the SuperNova/Acceleration Probe, or SNAP, almost since physicist Saul Perlmutter discovered dark energy in 1998.

By measuring how light from exploding stars is stretched as it travels toward Earth, Perlmutter calculated that the expansion of the universe was speeding up rather than slowing down as most scientists believed.

The reason for this unexpected acceleration is some sort of force that overwhelms the universe's gravitational pull. Because it is so mysterious, this force was dubbed dark energy.

Perlmutter recently won two prestigious international awards for his discovery, the Shaw Prize in Astronomy and the Feltrinelli International Prize in the Physical and Mathematical Sciences.

The next step is to find out exactly what this stuff is, and Perlmutter and physicist Michael Levi are hoping their probe will be the one to do that. The design includes a powerful telescope and a digital camera with nearly a billion pixels.

The Department of Energy has invested nearly $9 million in the SNAP project since 2003 and is a co-sponsor, along with NASA, of the dark energy mission.

"There are still many hurdles for us to clear on the NASA side," Levi said.

Two other teams will compete for the chance to launch their concept into space, one led by Johns Hopkins University and another by the National Optical Astronomy Observatory.

NASA has allocated $2 million to be divided by the three teams to take their designs to the next level where they are basically ready to be built for launch and the cost for each can be estimated.

The space agency will decide in 2009 whether or not to go ahead with whichever dark energy proposal is chosen.

"We are hopeful that given the impact of the science NASA will support this mission, but they have a lot on their plate," Levi said. "We are still hoping for a launch at the end of 2013."