Murchison Widefield Array

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Scores of big metallic spiders are springing up in the plains of Western Australia. They're not the result of some genetic experiment gone horribly wrong, though -- or even props for a bad movie. Instead, they're simple radio antennas that soon will be looking back to near the beginning of the universe -- and perhaps listening for ET.

The antennas form a radio telescope known as the Murchison Widefield Array. Each "spider" is a couple of feet tall, and contains several antennas. When the array is complete, a computer will combine the signals from all the antennas, providing a look at a wide swath of the radio sky.

One of the array's main goals is to study an era before the first stars and galaxies were born. Another is to look for brief outbursts of radio waves from exploding stars and other powerful objects.

Astronomers also plan to scour the array's observations for signs of intelligent life in other star systems. The array should be able to pick up the signals from powerful radio sources up to 30 light-years away, allowing it to "listen in" on about a thousand stars.

Scientists chose the array's location in part because there are almost no people around, so there's no radio "noise" to spoil the signals from astronomical radio sources. And to make sure it stays that way, laws restrict the kinds of radio sources that can be built in the region. Similar laws protect a radio observatory in the U.S. More about that tomorrow.

Script by Damond Benningfield, Copyright 2008

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