Scientists have risen to the challenge to design an experiment that will make measurements of millions of galaxies to probe dark energy in new ways.
December 05, 2012
“About 5 billion years ago the universe underwent a crucial transition. The gravitational tug that pulled together the matter in the universe was overwhelmed by a different, repulsive phenomenon. As a result, the universe began to expand at an accelerating rate. Scientists have given that phenomenon a name: dark energy. However, they can say with confidence only what it does, not what it is, where it comes from, or why it’s pushing galaxies apart at an ever more rapid speed.
Courtesy of: Sloan Digital Sky Survey
The Department of Energy recently declared the need to construct a powerful new device that scientists could use to address fundamental questions about dark energy. Scientists have proposed two different projects to fulfill this need. The projects aim to study the three-dimensional distribution and motions of galaxies before and after the transition epoch between the matter-dominated and dark-energy-dominated eras.
In the northern hemisphere, the proposed BigBOSS project would attach a spectroscopic instrument to the Mayall telescope atop Kitt Peak in southern Arizona. BigBOSS is a scaled up version of the BOSS spectroscopic survey. In the southern hemisphere, the proposed DESpec project would attach a spectroscopic instrument to the Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile, current home of the Dark Energy Survey. Lawrence Berkeley National Laboratory is the headquarters for the BigBOSS project, while Fermilab heads the design of DESpec.
Both of these projects would, in different ways, construct the largest three-dimensional maps of the cosmos ever made by collecting spectra of millions of galaxies—many times more than any previous spectroscopic survey.
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