Planetary destruction could cause nebulous clouds of dust
Friday, 04 November 2011Curious dust clouds that mask the supermassive black holes sitting at the center of most galaxies may be the crumbled remains of high-speed collisions between nearby planets and asteroids, according to a new theory. The new study is published in the journal of the British Royal Astronomical Society.
Scientists at Britain’s Leicester University suggest the powerful planetary crashes generate such tremendous energy that microscopic dust grains are all that eventually remain of the two colliding objects. The collisions are estimated to occur at speed of up to 1,000 kilometers per second.
The central parts of most galaxies are thought to contain supermassive black holes. Of the supermassive black holes that have been detected, about half are shrouded by a puzzling cloud of dust. If in addition to a supermassive black hole and stars, the inner region of the galaxy has planets and asteroids, then the new theory would be useful to explain the phenomenon.
The researchers say that unlocking the origin of the dust clouds helps to provide new clues about the enigmatic nature of supermassive black holes, including the one lying dormant at the center of our own Milky Way galaxy. The study's lead author, Sergei Nayakshin, said the collisions and the high levels of intense radiation would make it doubtful there would be life on any planet orbiting a supermassive black hole.
Scientific observations of collisions between asteroids and comets in our own solar system provided the inspiration for the work. Collisions such as these produce 'zodiacal dust', which would also be observed near supermassive black holes if similar rocky bodies were undergoing collisions in the region.
According to theory, nothing can travel fast enough escape from behind the veil of a black hole's event horizon. The ultra-dense mass of a supermassive black hole is millions of times greater than that of our Sun. Its powerful gravitational forces can capture anything from subatomic particles to stars, which are pulled apart and swirled into its void at nearly light-speed.
Outside of the event horizon, stars and planets - even other black holes - can orbit just as they would around any other locus of similar mass.
