Black Hole Eats Asteroids, Burps Out X-Rays

The supermassive black hole at the center of our galaxy may be constantly snacking on asteroids. A new study finds that asteroids at least 12 miles wide falling into the black hole would account for the regular bright x-ray flares seen through telescopes.

Though nothing, including light, can escape a black hole, most are ringed by a disk of gas and dust. As it falls in, this material heats up to incredible temperatures, generating energy.

For several years, NASA’s Chandra X-ray Observatory has spotted daily fluctuations in the emissions coming from the Milky Way’s central black hole. Known as Sagittarius A*, this 2-million- to 4-million-solar-mass black hole is approximately 26,000 light-years from Earth near the border of the constellations Sagittarius and Scorpius.

Sagittarius A*’s daily flares generally last a few hours and increase the black hole’s brightness by a hundred times. Scientists have been at a loss to explain why the black hole would have such regular eruptions.

Researchers now suggest that tens of trillions of asteroids and comets, stolen from their parent stars, might float around the black hole. If a 12-mile-wide (or larger) asteroid should get within 100 million miles of the black hole, tidal forces would rip it to shreds. These fragments would then fall in and be vaporized by friction as they encounter the gas and dust churning around the black hole.

The central supermassive black hole could sustain these regular flares for billions of years. Even at a rate of one asteroid per day, it would have only consumed a few trillion asteroids over the lifetime of the galaxy, leaving plenty of fodder.

An unfortunate planet coming loose from its parent star could also get ripped apart in this manner. Because planets are far less numerous than asteroids, this process would be much rarer. Were a planet to be eaten, it would produce a dramatic flare, brightening the black hole by a million times its normal output.

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