We know from observations of stars that distant objects are speeding faster and faster away from us as the universe expands. That's because the universe is expanding at an increasing rate. Scientists at Fermi National Accelerator Laboratory (Fermilab), Brookhaven National laboratory (BNL), SLAC National Accelerator Laboratory, and Lawrence Berkeley National Laboratory (Berkeley Lab) are eager to find out why. Recent observations by SLAC scientists may provide an answer. (Fermilab, SLAC, BNL, and Berkeley Lab are US national laboratories funded by the Department of Energy's Office of Science.)

Scientists have offered two explanations for the accelerating expansion of the universe. Either some type of mysterious energy - dark energy drives the expansion, or Einstein's General Theory of Relativity, which describes how gravity works, is incorrect on cosmic scales; that is, our understanding of gravity is incomplete and gravity behaves differently from what we expect. From current observations, scientists estimate that ~70% of the mass-energy of the universe is dark energy.

Scientists study the patterns of large galaxy clusters across the sky. These patterns provide information on the interplay between dark energy and gravity.

The measurement of significant number of galaxy clusters, their masses, and their distances from Earth were made, the data was compared with various dark-energy theories. The data supported the hypothesis that a form of dark energy drives the expansion of the universe. It gave additional credence to the vacuum-energy model, which describes how dark energy could come from the very vacuum of space.

To help find out the nature of dark energy Fermilab and 23 institutions in the U.S., Brazil, Spain, Germany, and the U.K. are building a powerful camera to attach to the Blanco telescope in the Chilean Andes. This camera will allow scientists to collect data on galaxy clusters further away than any we have been able to observe in the past.

The 570-megapixel Dark Energy Camera about 50 to 100 times the resolution of your typical home digital camera will have some impressive specifications. It will have 74 highly sensitive detectors called charge-coupled devices (CCDs), which will be cooled to -100 degrees Celsius to minimize background noise. The CCDs will record the long wavelengths of light that come from extremely distant galaxies and supernovae (exploding stars). DECam will also have the world's largest shutter and filter, each about five feet tall. With this camera, scientists will be able to see 300 million galaxies.

Vasil Sidorov on April 19, 2011 from Department of Energy's Office of Science Queltanews office,

Technopark QUELTA,

Nizhyn Laboratories of Scanning Devices