A Black Hole Could Grow as Large as 50 Billion Solar Mass
Stars with masses greater than about 20 times the mass of our Sun may produce black holes at the end of their lives and these matter-sucking monsters could get really big, according to a new study.
As we know that black hole emit light, but they can shine. They do so because of accretion disks, but those disks don’t appear around black holes. There could be incredibly huge black holes (maybe it could be size of out Milky Way galaxy) out in the universe that we can’t see, because they’ve gone really dark. So we can’t see them, but few time ago an international team of astrophysicist led by a Hopkins University scientist, witnessed a black hole swallowing a star and ejecting a flare of matter moving at nearly the speed of light. They observed a new way for plasma to escape the gravitational pull of a supermassive black hole.
Black holes at the heart of galaxies could swell to 50 billion times the mass of the sun before losing the discs of gas they rely on to sustain themselves, according to the University of Leicester research.
In a study known as How Big Can a Black Hole Grow? Professor Andrew King explored supermassive black holes at the center of galaxies, around which are regions of space where gas settles into an orbiting disc. This gas can lose energy and fall inwards, feeding the black hole. But these discs are known to be unstable and prone to crumbling into stars.
Andrew King calculated how big a black hole would have to be for its outer edge to keep a disc from forming, coming up with the figure of 50 billion solar masses.
The study suggests that without a disc, the black hole would stop growing, meaning 50 billion suns would roughly be the upper limit. The only way it could get larger is if a star happened to fall straight in or another black hole merged with it.
The significance of this discovery is that astronomers have found black holes of almost the maximum mass, by observing the huge amount of radiation given off by the gas disc as it falls in. The mass limit means that this procedure should not turn up any masses much bigger than those we know, because there would not be a luminous disc.
The study appears in Monthly Notices of the Royal Astronomical Society.
Professor Andrew King said that
Bigger black hole masses are in principle possible—for example, a hole near the maximum mass could merge with another black hole, and the result would be bigger still. But no light would be produced in this merger, and the bigger merged black hole could not have a disc of gas that would make light.
One might nevertheless detect it in other ways, for example as it bent light rays passing very close to it (gravitational lensing) or perhaps in future from the gravitational waves that Einstein’s General Theory of Relativity predicts would be emitted as it merged.
At this stage a new question arise what if 2 black hole collide? Could it make a black hole could make a black hole with a mass of up to 100 billion solar masses? Further information regarding How Big Can a Black Hole Grow? will publish soon at Cornell University Library.