The power of black holes to devour matter and light derives partly from magnetism, a new study shows.
Black holes form when a star collapses on itself. Light gets trapped inside and the holes therefore appear black.
The holes swell by attracting matter from stars and other nearby objects, a process called accretion.
Astronomers are able to study black holes by observing the glow emitted by matter falling in.
Researchers used NASA's Chandra X-ray Observatory to study a black hole thatgrew fromtwo stars, they report in Thursday's issue of the journal Nature.
"In 1973, theorists came up with the idea that magnetic fields could drive the generation of light by black holes," said astrophysicist and study author John Raymond of Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "Now, over 30 years later, we finally may have proof."
As theorized, the team found magnetism in the black hole coiled up like a spring. Magnetic fields produce a wind that helps draw gases into the black hole.
The wind fromthe black hole behaves as computer models predicted, the researchers said, adding evidence for the theory.