Rippling Encounters
When two equally massive black holes meet, astronomers had expected them to produce a gravitational mess -- turbulent waves in space and time. But new computer simulations are showing that such a meeting might be pretty calm. The gravitational waves might look smooth and even, like the ripples of a small rock dropped in a glassy pond.
So far, computers are the only way for astronomers to probe what happens when two black holes meet. But a space-based observatory that's scheduled for launch in the next decade could change that. It'll detect the gravitational waves from black-hole encounters and many other objects and events.
Any moving object should produce gravitational waves. The waves are so tiny, though, that they haven't been detected. A ground-based observatory began a full-time search for them late last year. The space-based observatory will be much more sensitive. Among many other things, it should detect close encounters between black holes.
In one type of encounter, a black hole that's a few times as massive as the Sun might pass close to one that's millions or billions of times as massive.
There's no way to "see" such encounters today, or to learn much about them. But their gravitational waves should tell astronomers the masses of the black holes, how they're moving, and what they're doing to the space-time around them -- providing a lot of new numbers for the computers to crunch.
Script by Damond Benningfield, Copyright 2006
For more information, visit StarDate's Black Holes Encyclopedia.
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
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