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Switching On

December 18, 2015

Some of the brightest lights in the universe can switch on and off like a lamp. Plug them in and they switch on; pull the plug and they switch back off.

Over the last few years, astronomers have watched one of these lights switch on. It’s in the galaxy NGC 660, which is about 40 million light-years away.

A supermassive black hole sits at the galaxy’s heart. It’s encircled by stars and gas. Very little of that material has been falling into the black hole, so the galaxy’s center has been quiet.

But a few years ago, astronomers measured a huge jump in the amount of radio waves coming from the galaxy. Follow-up observations showed that the outburst was coming from a small region in its center.

That suggests that a large amount of material suddenly fell toward the black hole, getting hotter and brighter as it did so. Powerful magnetic fields grabbed some of this super-heated gas before it could enter the black hole, directing it into powerful “jets.” These jets shoot into space at about 10 percent of the speed of light, producing radio waves and other forms of energy.

No one knows how long the outburst will last. It could fade quickly, or it could continue for a long time — until the plug gets pulled, and the black hole at the heart of NGC 660 goes dark once again.

NGC 660 is in Pisces, the fishes. The constellation is high in the south at nightfall, spreading out above and to the upper left of the Moon.

Script by Damond Benningfield, Copyright 2015

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