The Big Bang, the South Pole, and Everything
Spectrum's Glenn Zorpette reports from Antarctica
This is part of the series:
Antarctica: Life on the Ice
Transcript: The Big Bang, the South Pole, and Everything
Glenn Zorpette: The South Pole is a great place to study origins of the universe. Here’s why. One of the main things that cosmologists do is analyze the microwave radiation that permeates the universe. That radiation is called the cosmic microwave background, and you can think of it as an echo of the big bang that launched the universe into the glorious spectacle that we see today. With its dry, stable atmosphere, the South Pole offers outstanding viewing conditions for two microwave telescopes that could unravel the deepest mysteries of the universe.
Glenn Zorpette: Physicist John Carlstrom of the University of Chicago leads the way up to the roof of the South Pole Telescope. It towers five stories above the powdery white snow.
[clanking sound up for 1 to 2 seconds then fade]
John Carlstrom: This is a 10-meter diameter—it’s actually a little larger, but 10 meters as it’s projected toward the sky—telescope for looking at radiation from the big bang, what we call the cosmic microwave background radiation.
Glenn Zorpette: Carlstrom is the mastermind behind this [US] $19 million telescope. He explains that the cosmic microwave background radiation is like an echo reaching us from 13.7 billion years ago.
John Carlstrom: And it allows us to take a snapshot, see what the universe was like. So we can take telescopes like this and develop images of what this radiation looks like where it’s a little more intense and less intense, hot spots and cold spots. And when we develop these pictures and look at them, what we’re seeing is the baby infant picture of what our universe looked like.
Glenn Zorpette: Carlstrom’s studying these maps for clues to dark energy, the utterly mysterious force that makes up 70 percent of our universe. Astronomers know very little about dark energy, but they do know that it counteracts gravity and causes the universe to expand at an ever-increasing rate. One of the major mysteries of dark energy is that it can’t account for the formation of the largest structures in the universe, which are clusters of galaxies. Studying when these galactic clusters formed and how they’ve changed could answer some basic questions about the origins of our universe, such as: How important was dark energy in the early universe? When did it kick in? How has it evolved? In its search for answers, the South Pole Telescope scans the skies for galaxy clusters.
John Carlstrom: There’s a little shadow against the cosmic microwave background, and that shadow is because you’ve just detected a cluster of galaxies. So you’re looking at the largest object the universe has ever created, and you’re going to see it as a hole, a depression in the intensity of the cosmic microwave background. Fewer photons.
Glenn Zorpette: To detect those tiny temperature dips, the telescope’s photon detectors and one of its mirrors are kept extremely cold.
Glenn Zorpette: In a round chamber beneath the South Pole Telescope, superadvanced refrigerators keep the telescope’s mirror at 10 degrees kelvin. That’s about –450 degrees Fahrenheit—even the South Pole is blisteringly hot by comparison.
[sounds of helium pulsing]
John Carlstrom: It’s helium rushing through these lines—helium for our refrigerators. The refrigerators have this pulse of helium that goes in to cool the detectors.
Glenn Zorpette: In 2011, Carlstrom and his colleagues will move on to another huge cosmology topic—the theory of inflation, which says that the universe began expanding exponentially right after the big bang, when the entire universe that we see today was about the size of a grapefruit. Down the hall from the South Pole Telescope, another telescope, called BICEP, is already trying to test the theory. Harvard astronomer John Kovac leads the BICEP team.
John Kovac: There’s a specific pattern that would be characteristic of gravity waves that would have been created by an initial epic inflation in the first tiny fraction of a second if the universe underwent an inflationary expansion.
Glenn Zorpette: Translation? Okay. Inflation theory says that the explosive expansion of the universe would’ve created gravitational waves. And these waves would’ve left a signature, kind of like its own graffiti, in the cosmic microwave background. What would that graffiti look like? Well, think of it as a slight swirl in the radio signal. Graduate student Justus Brevik helped build the BICEP detectors that sense that swirling pattern.
Justus Brevik: What we do is we sit there and we scan the sky with these detector arrays and build up maps. And we have about an 800-square-degree field that we look at, and we scan over that for about a year and half to create a map of the polarization signal.
Glenn Zorpette: By studying the polarization of the microwave background, Carlstrom and his team may finally find hard evidence not only of gravity waves but also of inflation. Even in cosmological terms, that would be big.
John Carlstrom: What we would detect is what I think is, effectively, a smoking gun for inflation, for this incredible theory that the universe inflated from a subatomic region of space-time.
Glenn Zorpette: In other words, we’d have proof that the whole universe expanded from something much smaller than an atom. It would be the biggest news ever from the bottom of the world.