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Galactic Hub

August 13, 2015

It’s a good jaunt from the suburbs to downtown — a journey into bright lights, heavy traffic, and non-stop action. That’s especially true of the “downtown” region of the Milky Way — the galaxy’s core. It’s populated by some bright, massive stars that race around at high speeds. And those stars are packed together much more tightly than the stars out where we live, in the galactic suburbs.

The very heart of the Milky Way contains a black hole that’s about four million times the mass of the Sun. Gas or debris occasionally funnel into the black hole, causing a short flare-up before they disappear from view.

Thousands of stars orbit within a few light-years of the black hole. Most of them are fairly old and feeble. But there’s also a cluster of hot, young stars that are many times heavier than the Sun, and many thousands of times brighter. Some of these stars get so close to the black hole that they can whip around it at millions of miles per hour.

A ring of cold gas also encircles the black hole. It’s probably about 10 light-years across, give or take. It’s possible that the ring could fragment into smaller clumps, which could then collapse to give birth to new stars.

Many more stars lie not far outside the ring, including a couple of other big, bright clusters. So do ribbons of hot gas that are sculpted by strong magnetic fields, and much more — all part of our galaxy’s dynamic downtown.

We’ll talk about the distance to downtown tomorrow.


Script by Damond Benningfield, Copyright 2015

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