There, it will scan deep space for signs of dark energy, an invisible force that's pulling galaxies — and perhaps space itself — apart at faster and faster speeds.

“We’re going to survey 300 million galaxies in the southern sky to measure the speed of those galaxies,” said Tom Diehl, a physicist at Fermilab and a camera-construction leader. “We want to make the best description of the universe’s expansion to date.”

The faster an object moves away from the Earth, the more its light shifts toward a red color. Measurements of distant galaxies show all of them are red-shifted and moving away from us and each other.

“What's more, they’re moving away faster and faster, like pennies on the surface of an inflating balloon,” said Josh Frieman, an astrophysicist also working on the Dark Energy Survey effort.

Since the 1990s, astronomers suspected this expansion of space is accelerating because of a strange form of energy, dubbed dark energy because of its baffling nature. The new survey should improve red-shift measurements by about four to five times, Diehl said, helping get to the bottom of the mystery.

“We don’t know why the universe is speeding up, and that’s precisely why we’re doing the Dark Energy Survey,” Frieman said. “We’re trying to pin down the nature of dark energy.”

Since 2008, roughly 120 astronomers, engineers, and physicists have worked on the camera. As its construction comes to a close, we take a look at the Dark Energy Camera’s progress.

Above:

Video: Building the Test Mount

Time-lapse footage of the Dark Energy Camera’s test mount being built from January to October 2010. Fermilab

Authors: Dave Mosher

to know more click here