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Milky Way’s Heart V

September 30, 2011

Over the last couple of decades, astronomers have probed the heart of the Milky Way galaxy in amazing detail. They’ve confirmed that a giant black hole lurks at the galaxy’s center — something that wasn’t a surprise. But another discovery was a surprise. UCLA astronomer Andrea Ghez explains:

GHEZ: What we realize is that all the stars that we were using as probes of the black hole, they were all young. You don’t expect to see young stars near a black hole because a black hole is not a nice neighbor to a stellar nursery. Black holes tend to shred things apart. And to get stars to form you need a very gentle environment that allows big, fragile clouds of gas and dust to collapse under their own self gravity. So if you have a black hole right next to you which shreds the cloud apart, it’s very hard to imagine how to get stars to form. So it’s an interesting problem, we call this the paradox of youth. How in the world do you get these young stars in a region where you just don’t expect them.

The young stars could have formed farther from the black hole and quickly moved inward. Or they might not be young at all — they might simply look young. Or perhaps they formed just where they are now in one massive burst of starbirth, says Mark Morris, also of UCLA:

MORRIS: The stars that form in the galactic center, at first sight, seem to form in these incredibly rich clusters that form all at once, in one fell swoop, 10,000 stars, bang!

It’ll take more years of observations to solve the puzzle of the young stars in the heart of the Milky Way.


Script by Damond Benningfield, Copyright 2011


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