'Spewing' black holes can prevent the births of stars

The most massive andpowerfulblack holes preventthe birthof stars in their galaxy, researchers have learned.

Black holes, regions of space thatcanweigh millionsor billionstimes more than the sun, are believed to be found at the centre of all galaxies, including our own Milky Way.

Larger galaxies tend to have more massive black holes, but scientists using the European Space Agency's Herschel Space Observatory have found that galaxies with particularlyactive, massive black holesproduce fewer stars. The research, led by Dr. Mat Page of University College London, was published in Thursday's edition of the journal Nature.

While it's easy to imagine a black hole killing stars by eating them whole, the researchers say it's actually has more to do with what the black holes are spitting out.

Contrary to the popular image, black holes do not immediately consume objects in their entirety. Some of the material is drawn into the black hole, while some is shot into space.

Gas falling into black holes releases huge amounts of energyfor instance,a star's death by black holecaptured bya NASA satellite in 2010packed apunch similar to a supernova.

"Astronomers think that if an active black hole flares up too much, it starts spewing radiation that prevents raw material from coalescing into new stars," NASA said on its website.

However, scientists still don't understand the exact connection between black holes and star formation.

"We want to know more about how this process works," Bill Danchi, a Herschel program scientist, told the NASA site."Does star formation get disrupted from the beginning with the formation of the brightest galaxies of this type, or do all active black holes eventually shut off star formation, and energetic ones do this more quickly than less active ones?"