Giant Camera Will Hunt For Signs Of Dark Energy

Aug 22, 2011
Originally published on August 22, 2011 6:54 pm

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.

And the lenses are huge and heavy, too — with the largest lens about 3 feet across. This camera is also incredibly sensitive.

After it's mounted on the Blanco 4-meter telescope, high in the Chilean mountains, later this year, the camera will survey a large part of the sky for faint galaxies at the distant reaches of our universe.

By studying these galaxies, scientists hope to learn more about dark energy. "I think this probably is the first camera that's been designed just to do dark energy," says Flaugher.

Understanding Dark Energy

Dark energy was discovered only recently. In 1998, two different research teams saw the first evidence for it as they looked at the light coming to Earth from exploding stars in faraway galaxies.

"What we were really measuring was how far away the galaxies were, and they were much farther away than they should be, just based on gravitation," says Nicholas Suntzeff, an astronomer at Texas A&M University.

This meant something was acting against gravity. It's as if you threw a rock up in the air and instead of slowing down and coming back, the rock kept shooting up faster and faster, says Suntzeff.

"You'd think that would be really weird," he says. "That's antigravity. Well, the same thing happened with the galaxies." As galaxies move apart from each other, they are speeding up, going faster and faster instead of slowing down.

Suntzeff says it seems as though space itself has a natural ability to push away all other space around it. "That's what the equations are saying, that every piece of space, it's like it doesn't like anything else around it," he explains. "It's constantly pushing everything away."

As it does that, new space is created in between, Suntzeff says, "but that new space that's created will see the other pieces of space and then push on that, which makes it a process which goes faster and faster and faster."

'A Disturbing Idea'

This means the universe is not only expanding — that expansion is speeding up. Suntzeff says it seems that the universe is flying apart, and galaxies will ultimately disappear in the sky — everything will go cold and dark.

"That's a disturbing idea, both philosophically and theologically," Suntzeff says, noting that the world's religions hold that things either renovate themselves or go to some place with eternal life.

It's a challenging idea for science, too. Suntzeff recently served on an expert task force established to advise the government on future needs for dark energy research. It concluded that so far, science hasn't come up with any good explanations for why dark energy exists, and it recommended "an ambitious observational program to determine the dark energy properties as well as possible."

No one can photograph dark energy itself. But Flaugher says the new camera will look for the effects of dark energy by gathering data on more than 300 million galaxies whose faint light has been traveling toward Earth for a very long time.

"With this camera we'll be able to go back about 6, 7 billion years, so about three-quarters to half-way back to the Big Bang," she says.

This will let researchers look back at how the universe has been expanding in the past, and see how dark energy may shape the universe's future.

Copyright 2013 NPR. To see more, visit http://www.npr.org/.

Transcript

MELISSA BLOCK, host: From NPR News, this is ALL THINGS CONSIDERED. I'm Melissa Block.

ROBERT SIEGEL, host: And I'm Robert Siegel. A giant and powerful digital camera is about to be shipped from a lab near Chicago to a telescope high in the Chilean mountains. The camera is designed to help scientists study a mysterious part of the universe called dark energy. NPR's Nell Greenfieldboyce reports that dark energy makes up most of our universe, but scientists know almost nothing about it.

NELL GREENFIELDBOYCE: The camera is sitting inside a building at the Fermi National Accelerator Laboratory. Physicist Brenna Flaugher says its basic technology would be familiar to anyone who uses a digital point-and-shoot.

Dr. BRENNA FLAUGHER: The camera that we built is really very similar to the digital cameras we can buy at Wal-Mart or wherever.

GREENFIELDBOYCE: But this camera is big, so big that its guts fill a shiny cylinder that's about the size of a car engine.

FLAUGHER: This thing weighs almost a ton. The lenses for it by themselves and the barrel that's like the telephoto lens you stick on the front of your camera, that weighs another sort of ton. The largest lens is about a meter in diameter so that we have a very wide field of view.

GREENFIELDBOYCE: And this camera is also incredibly sensitive. After it's mounted on a telescope later this year, it will survey a large part of the sky for faint galaxies at the distant reaches of our universe. By studying these galaxies, scientists hope to learn more about dark energy.

FLAUGHER: I think this probably is the first camera that's been designed just to do dark energy.

GREENFIELDBOYCE: Dark energy was discovered only recently. In 1998, two different research teams saw the first evidence for it. They were looking at the light coming to Earth from exploding stars in faraway galaxies.

Dr. NICHOLAS SUNTZEFF: What we really measured was how far away the galaxies were, and they were much farther away than they should be, just based on gravitation.

GREENFIELDBOYCE: That's Nicholas Suntzeff, an astronomer at Texas A&M University. He says this meant something is acting against gravity. It's as if you threw a rock up in the air. And instead of slowing down and coming back, the rock kept shooting up faster and faster.

SUNTZEFF: You'd think that would be really weird. That's antigravity. Well, the same thing happened with the galaxies. We see that our galaxies, as they're moving apart, instead of them slowing down like they should - that there was just a rock in the air - they're actually speeding up, going faster and faster.

GREENFIELDBOYCE: Suntzeff says it seems as though space itself has a natural ability to push away all other space around it.

SUNTZEFF: That's what the equations are saying, that every piece of space, it's like it doesn't like anything else around it. It's constantly pushing everything away.

GREENFIELDBOYCE: As it does that, new space is created in between.

SUNTZEFF: But that new space that's created will see the other pieces of space and then push on that, which makes it a process which goes faster and faster and faster.

GREENFIELDBOYCE: This means the universe is not only expanding, that expansion is speeding up. Suntzeff says it seems that the universe is flying apart. Galaxies will ultimately disappear in the sky, all will go cold and dark.

SUNTZEFF: That's a disturbing idea, both philosophically and theologically. In almost all theologies, things either renovate themselves or you go to some place where there's eternal life. And the idea the universe is just going to expand forever and kill itself is not natural for us to think that's what's going to happen, that everything ultimately will perhaps be destroyed.

GREENFIELDBOYCE: It's a challenging idea for science too. Suntzeff recently served on an expert task force that looked at dark energy and concluded that so far, science hasn't come up with any good explanation for why it exists.

FLAUGHER: There's enough data that people know what we don't understand, but there's not enough data to explain it yet. There's too much room for the theorists to come up with crazy ideas right now. And so there's lots of crazy ideas, but we need data.

GREENFIELDBOYCE: That's where the big, new camera comes in. Flaugher says no one can photograph dark energy itself, but the camera will look for the effects of dark energy by gathering data on more than 300 million galaxies whose faint light has been traveling towards Earth for a very long time.

FLAUGHER: With this camera, we'll be able to go back about six, seven billion years, so about, you know, three-quarters to halfway back to the Big Bang.

GREENFIELDBOYCE: This will let them look back at how the universe has been expanding in the past and how dark energy may shape its future. Nell Greenfieldboyce, NPR News. Transcript provided by NPR, Copyright NPR.