(Describer) Streams of light collide to create a globe filled with water. Title: Science Nation. A man looks at a monitor.

Here is the temperature outside, which at the moment, is -71 degrees.

(male narrator) Physicist Francis Halzen is on the hunt for mysterious subatomic particles that saturate our universe-- neutrinos. His lab? It's a cubic kilometer full of sensors known as IceCube, and its buried below the South Pole.

(Describer) A bright flash sets off red matter spreading.

[explosion roars]

(narrator) Astronomers say neutrinos are key to understanding the workings of the cosmos. Energetic events like exploding stars and black holes emit them, but studying them has turned out to be a tall order. There is basically no difference between neutrinos and light. The only difference is that light doesn't even go through a wall, whereas neutrinos go through everything.

(narrator) Everything including earth. But it is possible to detect neutrinos using sensors embedded in ice.

(Describer) A sphere goes down a hole.

(Halzen) And so just accidentally, they run straight into the nucleus of an atom, and then create lots of other particles which we can't see. And it's only these accidental caches of neutrinos that allow us to observe them.

(Describer) A large cylinder is towed.

(narrator) Halzen's team at the University of Wisconsin created the IceCube Neutrino Observatory with support from the National Science Foundation. It's like a telescope looking inside the earth instead of towards the sky, watching for these ghostly particles from distant galaxies.

(male) We're looking at an IceCube Digital Optical Module, or DOM.

(Describer) The sphere.

We've put this in the ice. It has a photomultiplier tube.

(Describer) Terry Benson:

It's a light bulb in reverse. It picks up light and sends an electrical signal to this top section, which is a high-powered computer.

(narrator) About 5,000 DOMs have been lowered on cables and permanently frozen into the ice. If you were standing at IceCube's location

(Describer) Jon Dumm:

and looked out everywhere, this is what you'd see.

(Describer) An oval on a monitor.

We hope to find an accumulation of events leading us to a source of neutrinos.

(narrator) Retracing the path of these very small particles could help answer very big questions about supernovas, dark matter, and the very origins of the universe.

(Describer) The globe turns.

For Science Nation, I'm Miles O' Brien.