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January 13, 2015

A long time ago, in a galaxy far, far away, a black hole grabbed a quick snack — it ripped away some gas from the surface of a nearby star. The light from this encounter reached Earth a year ago — 650 million years after it happened.

When a star meets a black hole, the encounter always produces some fireworks. In some cases, the black hole rips the star to bits. The star’s gas then spirals into the black hole, flaring millions of times brighter than the star itself as it does so.

Occasionally, though, instead of gorging on an entire star, the black hole just grabs a snack. It takes part of the star, but leaves most of it intact.

That’s what happened to a system that’s in a galaxy in Ursa Major, the big bear.

A new automated telescope saw the flare-up last January. At first, astronomers thought it was an exploding star or some similar event. But over the following few months, they watched it with several telescopes on the ground, plus an X-ray telescope in space. The details of the outburst didn’t match those of an exploding star.

Instead, the astronomers deduced that the fireworks were produced by a grazing encounter between a star and a black hole. The black hole stole enough gas from the star to make a planet as big as Jupiter, the giant of our own solar system. The gas flared brightly as it spiraled into the black hole. But the star remained just far enough away from the black hole to escape — a little lighter, perhaps, but otherwise intact.


Script by Damond Benningfield, Copyright 2014

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