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Underground Astronomy III

March 3, 2011

Most of the action in a star takes place deep in its heart, where lightweight elements fuse together to make heavier ones. We can't see the action, though, because energy produced in the core takes thousands of years to work its way through a star's outer layers of gas.

But the fusion reactions also produce ephemeral particles that race through the star's outer layers undisturbed. Known as neutrinos, the particles carry important information about the process that powers the stars.

Neutrinos are hard to study, though, because they zip through normal matter -- like stars and planets -- without stopping. In fact, trillions of them pass through your body every second.

Every once in a great while, though, a neutrino does interact with normal matter -- giving astronomers a chance to study a few of them. But there's a complication: other forms of energy can mimic a neutrino's signal.

The solution is to place the detectors far underground, and scientists have been doing just that for years. They've placed the instruments at the bottom of deep mines, for example, and even deep beneath the surface of the Mediterranean Sea. And the biggest neutrino "telescope" to date is buried deep in the ice at the South Pole. Its thousands of detectors are looking for flashes of light created when neutrinos zap atoms in the ice -- providing new insights into the inner workings of the stars.

More about underground astronomy tomorrow.

Script by Damond Benningfield, Copyright 2011

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