银河系黑洞正吞食小行星

The giant black hole at the center of the Milky¹ Way may be vaporizing and devouring²（吞食，毁灭） asteroids⁴, which could explain the frequent flares⁶ observed, according to astronomers⁷ using data from NASA's Chandra X-ray Observatory⁸. For several years Chandra has detected X-ray flares about once a day from the supermassive black hole known as Sagittarius A*, or "Sgr A*" for short. The flares last a few hours with brightness ranging from a few times to nearly one hundred times that of the black hole's regular output. The flares also have been seen in infrared⁹ data from ESO's Very Large Telescope in Chile.

"People have had doubts about whether asteroid³s（小行星） 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 Astronomical¹⁰ Society. "It's exciting because our study suggests that a huge number of them are needed to produce these flares."

Zubovas and his colleagues suggest there is a cloud around Sgr A* containing trillions of asteroids and comets, stripped from their parent stars. Asteroids passing within about 100 million miles of the black hole, roughly the distance between Earth and the sun, would be torn into pieces by the tidal forces from the black hole.

These fragments then would be vaporized by friction¹¹ as they pass through the hot, thin gas flowing onto Sgr A*, similar to a meteor heating up and glowing as it falls through Earth's atmosphere. A flare⁵ is produced and the remains¹² of the asteroid are swallowed eventually by the black hole.

"An asteroid's orbit can change if it ventures too close to a star or planet near Sgr A*," said co-author Sergei Nayakshin, also of the University of Leicester. "If it's thrown toward the black hole, it's doomed¹³."