When Did Dark Energy “Turn On” in the Universe?

6a00d8341bf7f753ef01348511a70d970c-320wi Some scientists believe that about 7 billion years ago, the still unknown repulsive force called dark energy "turned on" to speed the expansion of the universe that continues to this day. University of California, Berkeley astronomers have won approval for a telescope project that will reach back in time more than 10 billion years to probe the role of mysterious dark energy in speeding the early expansion, and allow scientists to map the entire universe in greater detail than ever before.

Astronomer David Schlegel of the Lawrence Berkeley National Laboratory said it will involve 35 science institutions around the globe and will result in the biggest map of the universe ever created.

"This is a project that people have been screaming to do for years," Schlegel said Tuesday. "The universe itself is really unmapped today."

The map would be 10 times larger and more detailed than a map currently being created by the Sloan Digital Sky Survey, which has been studying the heavens for the past 10 years using a telescope in New Mexico.

Although approval by the National Science Foundation and its National Optical Astronomy Observatory is still conditional, Schlegel said, only technical hurdles remain before the international project receives a final go-ahead.

The venture, led by the Berkeley lab's scientists, bears the name BigBOSS. It will employ the powerful 4-meter Mayall Telescope on Kitt Peak outside Tucson to observe some 50 million astronomical objects in the ancient universe. The project's name stands for the obscure Big Baryon Oscillation Spectroscopic Survey.

By scanning the very deepest regions of the sky, the astronomers will be gathering light from stars formed billions of years ago – in effect, the telescope will be seeing the universe as it existed that far back in time.

A French astronomical consortium will build a powerful new $15 million spectrograph for the Kitt Peak telescope to analyze the ancient starlight at varied frequencies of the spectrum.

In a highly specialized Shanghai factory, Chinese astronomers will create an array of 5,000 small robots programmed to select the 20 million specific faint galaxies many light-years away for observation at the telescope through fiber optic networks.

A highly specialized electronic detector called a Charge Coupled Device, or CCD, will be built at the Berkeley lab's microsystem's laboratory under the direction of Natalie Roe, a leading instrument scientist there. The instrument will be highly sensitive in the red and infrared wavelengths to gather images of the most distant objects in the sky, according to Michael Levi, the BigBOSS project's director.

The international venture has been under development for more than a year and a half, and its equipment is expected to be complete and in operation by 2016, Schlegel said. It is designed to do the same job with a ground-based telescope as NASA's proposed $1.7 billion Joint Dark Energy satellite, which is not expected to fly before 2020.

The Daily Galaxy via sfgate.com and Berkeley Labs

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