the-dark-energy-survey-begins
The latest, greatest hunt for dark energy has begun, with a massive camera installed on a Chilean mountaintop returning the first of millions of photographs that should help astronomers learn more about the strange forces driving our universe's evolution.
The photos were released Sept. 12 by the [Dark Energy Survey Collaboration](http://www.darkenergysurvey.org/), operators of [the 570-megapixel Dark Energy Camera](http://stag-komodo.wired.com/wiredscience/2010/11/dark-energy-survey-camera/), the most powerful astronomical imager ever built.
"It works like other digital cameras, only it's much larger, much more sensitive, and mounted on a large telescope," said astronomer Josh Frieman of the University of Chicago, the Dark Energy Survey's director.
"We're using it to get a much better measurement of cosmic expansion in the universe," Frieman continued. "We're going to measure the evolution of structure in the universe. And the way to do both those things is to do a really big survey of the sky."
Over the next five years, the camera, set inside the Blanco telescope in the arid mountains of Chile's high-altitude Atacama desert, where stars shine with a clarity seen in few other places on Earth, will photograph no fewer than 300 million galaxies.
After categorizing those galaxies according to age, form and distance from Earth -- the camera is sensitive enough to detect light emitted 8 billion light years away -- astronomers should better understand how galaxies swirl and cluster over deep time, and also how the universe expands.
In the 1990s, images from the Hubble telescope showed astronomers that the universe, which had been thought to expand at a steady speed, is actually expanding at an ever-accelerating rate. [Dark energy](https://en.wikipedia.org/wiki/Dark_energy) was the name given to the hypothetical force that must drive that strange acceleration.
In addition to measuring the dynamics of expansion, researchers will also search images from the Dark Energy Camera for [subtle distortions caused as dark-energy tugs on photons](stag-komodo.wired.com/wiredscience/2010/08/lensing-dark-energy/) traveling through space, a sort of universe-scale blur.
On the following pages, Wired looks at some of the Dark Energy Survey's first pictures.
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Fornax Cluster Detail
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Detail of Dark Energy Camera image of the barred spiral galaxy NGC 1365, part of the Fornax cluster of galaxies.
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REIDAR HAHN05
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