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October 15, 2010

Astronomers love to hunt for fingerprints. Chemical elements leave the fingerprints in the light of the stars. The Big Bang left its fingerprints in the background radiation that fills the universe. And a team of astronomers will soon be looking for the fingerprints of dark energy.

Their tool is HETDEX -- the Hobby-Eberly Telescope Dark Energy Experiment. It'll use the Hobby-Eberly Telescope at McDonald Observatory to measure the locations and motions of galaxies when the universe was billions of years younger.

Dark energy makes up most of the universe, and it's causing the universe to expand faster as it ages. So far, though, scientists can't explain it.

A key measurement is how the expansion rate of the universe has changed. And another is the way galaxies are sprinkled through the universe. There should be a pattern in the distances between them -- the "fingerprint" of dark energy.

KOMATSU: We essentially measure the locations of galaxies -- a million galaxy locations. And then, from that location we determine distances to galaxies, and also distances between galaxies. Now distances to galaxies will tell us something about dark energy, but the distances between those galaxies will tell us something else about the dark energy.

Eiichiro Komatsu is the director of the Texas Cosmology Center and a member of the HETDEX team.

KOMATSU: We don't have to know what the dark energy is to make these measurements. We just go ahead and measure them and try to interpret them in terms of the nature of dark energy.

HETDEX will get underway over the next few years.


Script by Damond Benningfield, Copyright 2010

Today's program was made possible in part by the NASA Science Mission Directorate.

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