It has long been established that anything caught in the gravitational well of a black hole is doomed to eventual disintegration. Scientists at the University of Leicester in the United Kingdom, after studying the bursts of X-rays emitted from the edges of the central supermassive black hole of our own Milky Way galaxy, have concluded that the detected flares emanate from the break-up of asteroids.
It appears, according to the study reported in the Monthly Notices of the Royal Astronomical Society, that the black hole, which scientists refer to as Sagittarius A* (Sgr A* for short), is devouring bodies that get a little too close. Its diet seems to consist of at least one asteroid a day.
Findings also suggest that the supermassive black hole is surrounded by trillions of asteroids and cometary objects that have been pulled away from their parent stars or perhaps captured if they happen to be of the "rogue" variety. The asteroid population estimate was derived from the assumption that the stars surrounding the black hole would have belts of asteroids and comets roughly the same size of those within the Solar System.
"People have had doubts about whether asteroids could form at all in the harsh environment near a supermassive black hole," said Kastytis Zubovas, lead author of the paper. "It's exciting because our study suggests that a huge number of them are needed to produce these flares."
Even given the consumption rate of an asteroid or comet per day, Sagittarius A* should be dining from its own belt for a very long time.
Sera Markoff of the University of Amsterdam (Netherlands) and co-author of the studya, explained: "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. Only a small fraction of the total would have been consumed, so the supply of asteroids would hardly be depleted."
The astronomers were able to draw their conclusions after studying data gathered from NASA's Chandra X-Ray Observatory.
It is posited that the daily X-Ray flares result from the vaporization of asteroids that are drawn to within 100 million miles of Sagittarius A*, which is roughly the distance between the Earth and the Sun. The passing bodies are then torn apart by the extreme gravitational tidal forces at work at the black hole's outer edge.
The University of Leicester researchers believe that the asteroids and/or comets have to be at least six miles in diameter to produce enough energy when vaporized to display flares that can be seen by the Chandra X-Ray Observatory.
The study follows another out of the University of Leicester -- and also published in the Monthly Notices) that indicated that the large doughnut-shaped dust clouds found around about half of the supermassive black holes (some completely obscured by centralized dust clouds) at galactic cores. According to Dr. Sergei Nayakshin, who led a team of international researchers, the dust is theoretically the result of large rocky bodies the size of planets colliding at such speeds as to pulverize the them. The theory is derived from observing the effects of collisions within our own Solar System, where rocky bodies leave behind what is called "zodiacal dust."
The Chandra X-Ray Observatory was launched in 1999 and is managed by NASAs Marshall Space Flight Center in Huntsville, Ala. It is the world's most powerful telescope and, according to the NASA website, is about a billion times more powerful than the first X-Ray telescope invented just three decades ago.
(photo credit: NASA, Wikimedia Commons)