Giant Camera Will Hunt For Signs Of Dark Energy
by Nell Greenfieldboyce
August 22, 2011 A giant and powerful digital camera is about to be shipped from a lab near Chicago to a telescope in Chile to study a mysterious part of the universe called dark energy.
Dark energy makes up most of our universe, but scientists currently know almost nothing about it except that it seems to be making the expansion of our universe speed up.
"There's enough data that people know what we don't understand, but there's not enough data to explain it yet," says Brenna Flaugher, a physicist at Fermilab near Chicago, which assembled the Dark Energy Camera. "There's too much room for the theorists to come up with crazy ideas right now. And so there's lots of crazy ideas. And we need data."
That's where this new 570-megapixel camera comes in. Flaugher says its basic technology would be familiar to anyone who uses a digital point-and-shoot. "The camera that we built is really very similar to the digital cameras you can buy at Walmart or wherever," she says.
But this camera is big — its guts fill a shiny cylinder that's about the size of a car engine. "This thing weighs almost a ton," says Flaugher.
More:
http://www.npr.org/2011/08/22/139849705/giant-camera-will-hunt-for-signs-of-dark-energyhttp://hetdex.org.nyud.net:8090/images/other_projects/04194a.jpgDark Energy Survey
A large international collaboration will probe dark energy with not one or two techniques, but four, using a giant new camera attached to a telescope in Chile.
Two techniques used by the Dark Energy Survey (DES) will map the distribution of galaxies in the universe.
One of them will plot more than 10,000 galaxy clusters that are spread across a wide region of the sky. DES will work with the South Pole Telescope, which will chart the energy output of thousands of clusters in the southern sky. DES will measure the distances to these same clusters. The combination of distance and energy output will reveal the mass of the clusters, including their dark matter, as well as their distribution through the universe. Different models of dark energy predict different distributions of galaxy clusters, so maps of the real distribution will help astronomers narrow down the list of possible explanations.
The second galaxy technique will measure the spacing between galaxies at different times in the history of the universe to search for a pattern imprinted in the Big Bang. The pattern grows with the universe as the universe expands. Its exact growth rate reveals how fast the universe has expanded at different times in history, which reveals the influence of dark energy at those times.
DES also will search for supernovae in distant galaxies, which is the same technique used to discover dark energy in the 1990s. And it will carefully measure the shapes of very distant galaxies to see how their light has been distorted by the gravity of dense clusters of galaxies. Like the other galaxy techniques, this one reveals the distribution of dark matter, which is influenced by dark energy.
More:
http://hetdex.org/other_projects/des.phphttp://upload.wikimedia.org.nyud.net:8090/wikipedia/commons/thumb/f/f1/Tololo_a.JPG/325px-Tololo_a.JPG