These X-ray flares have been detected for years coming off the supermassive black hole known as Sagittarius A.  Nasa says that for the few hours they last they burn a few times to a hundred times as bright as the black holes regular output. Chile’s Very Large Telescope has also observed the flares.

"People have had doubts about whether asteroids could form at all in the harsh environment near a supermassive black hole," said Kastytis Zubovas of the University of Leicester in the United Kingdom, and lead author of the report appearing in the Monthly Notices of the Royal Astronomical Society. "It's exciting because our study suggests that a huge number of them are needed to produce these flares."

According to Zubovas and his colleagues there is a cloud around Sagittarius A containing asteroids and comets stripped from their parent stars, and those asteroids passing within 100 million miles of the black hole (about as far as the earth is from the sun) end up getting torn to pieces by the black hole’s tidal forces.

"As a reality check, we worked out that a few trillion asteroids should have been removed by the black hole over the 10-billion-year lifetime of the galaxy," said co-author Sera Markoff of the University of Amsterdam in the Netherlands. "Only a small fraction of the total would have been consumed, so the supply of asteroids would hardly be depleted."

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