Milky Way’s Heart IV
GHEZ: The picture that we now have is there is, without a question, a large, supermassive black hole at the center of our galaxy, and that it is consuming very little material.
UCLA astronomer Andrea Ghez is studying the center of the Milky Way galaxy. The black holes at the hearts of some galaxies are surrounded by big, hot, bright disks of gas. But the black hole at the center of the Milky Way is quiet. Something is happening there, but not much.
GHEZ: You could say that rather than having a huge feast, this is a black hole that’s having a little snack. You can see a little bit of light emerging from the very center and it’s flickering on a short time scale, so it’s like a little Christmas light.
But about a century ago as seen from Earth, it might have devoured a passing star, staging a pyrotechnic display that was brighter than a supernova. Mark Morris, who’s also at UCLA, explains:
MORRIS: We’re seeing evidence that there was a tremendous flash of X-rays, one or a few hundred years ago, near the center of our galaxy. We can’t really pinpoint where, but it could easily have been the central supermassive black hole eating a star. That’s the kind of flash you would get if the black hole ate a star. It should happen actually once every 10 or 20 thousand years according to the current estimates, and that would be a really fantastic display, because it would put out about as much energy as 10 supernovae when that happens. It’s a really quite a flashy show.
More about the galaxy’s flashy heart tomorrow.
Script by Damond Benningfield, Copyright 2011
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