Gravitational Waves II
When Galileo first turned his telescope toward the heavens, he discovered that the Milky Way is really a panoply of stars, and that Jupiter has moons. When the first gamma-ray telescope was launched into space, it discovered powerful bursts of energy from beyond the galaxy. And as other types of telescopes opened more "windows" on the universe, they allowed scientists to decipher more of its mysteries.
A new window may be about to open - a window on gravity.
Albert Einstein's theory of General Relativity predicts that gravity should travel through the universe as waves. Almost everything that moves should produce gravitational waves - from people to black holes. So far, though, no one has detected a single wave. That's because the waves are tiny.
But the technology may be about ready to "feel" these ripples in space-time from some of the most violent events in the universe, like collapsing stars.
Physicists are putting the final touches on a gravitational-wave observatory, called LIGO. It consists of two detectors - one in Louisiana, the other in Washington state. The detectors use lasers to measure the sizes of long tubes. When a wave passes through Earth, it briefly squeezes and stretches our planet and everything on it. If a big-enough wave passes through, it should alter these tubes just enough for scientists to detect them - confirming that gravity ripples through the universe.
More about relativity tomorrow.
Script by Damond Benningfield, Copyright 2005
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