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Falling into a black hole.

Falling into a black hole

The current standard theory of quasars proposes that these bright, starlike, but extragalactic objects have black holes at their centers. The extremely high flux of radiation coming out of a quasar is generated by the gravitational energy of matter falling into the black hole. Plenty of secondary evidence supports this picture. Now Martin Gaskell of Ohio State University in Columbus presents what seems to be the first direct evidence for gas falling into a black hole.

The evidence comes from studies of the spectra taken by the International Ultraviolet Explorer satellite of the radiation from a gas cloud in the galaxy NGC 4151. Analysis of the details of the shapes of the lines in these spectra show that the predominant motion of the cloud is inward, Gaskell says. He believes he can exclude outflow to a 99.9 percent confidence limit. From knowledge of this inflow he can estimate the mass of the black hole at 60 million times that of the sun. It may be the center of a very weak quasar, he says, and he concludes, "Accretion [of matter] on black holes in quasars is now on an observational footing."
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Author:Thomsen, Dietrick E.
Publication:Science News
Date:Jul 19, 1986
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