There’s probably more than one way to make a black hole. One is the collapse of a massive star. Another is the merger of two other dead stars, known as neutron stars. Such a merger would produce a brilliant outburst of energy. It would also produce an outburst of ripples in spacetime known as gravitational waves.
A gravitational-wave observatory known as LIGO will be looking for these mergers when it completes a major upgrade in a few years. Scientists say it should be able to detect any such merger within about 50 million light-years — perhaps dozens of them every year.
Alan Weinstein is a physicist who’s working on the LIGO project.
WEINSTEIN: The first thing it would tell us is that black holes — astrophysical black holes really are the objects described theoretically from Einstein’s equations. Einstein’s equation tells us that what black holes are is not dense matter but more or less infinitely curved space. It’s a different kind of an object. We don’t have direct evidence that such objects actually exist.
MIT physicist and LIGO pioneer Rainer Weiss says the gravitational waves would also reveal important details about the mergers.
WEISS: The thing that everybody’s going to ask is what happens when they crash into each other. That’s going to be a test of what nuclear physics is like. How do you suppose these neutron stars bounce when they hit each other, do they splash, what’s the equation of the state of nuclear matter in these stars and so forth. Gravitational radiation will tell you that, more than anything else, because it can look right through the thing and it doesn’t get disturbed by anything. That’s the nice thing about gravitational waves. You can get a real nice view of what’s going on inside.
Script by Damond Benningfield, Copyright 2011
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