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. Last Updated: 07/27/2016

40 Million Suns' Worth of Black


TUCSON, Arizona -- Using a series of radio telescopes stretching 5,000 miles across the United States from the Virgin Islands to Hawaii, an international team of astronomers has discovered strong evidence of an incredibly powerful black hole as massive as 40 million suns.

The findings, published Thursday in the journal Nature, are considered the strongest evidence yet of the existence of black holes, those mysterious objects that are so dense that not even light can escape their grasp.

"We think it's a black hole,'' said James Moran of the Harvard-Smithsonian Center for Astrophysics, one of the project's leaders. "But this is not going to be the last word.''

It is difficult to prove the existence of black holes -- primarily because, by definition, they can never be seen. At best, scientists can only study the effects that would be expected in the surrounding territory if a black hole were, in fact, present. By several accounts, Moran's project has come closer than any others.

"My mind is blown,'' said galactic expert Vera Rubin of the Carnegie Institution. "I would say this is compelling evidence'' of a black hole.

"A jury would convict,'' added Paul vanden Bout, director of the National Radio Astronomy Observatory, which runs the radio telescopes used in the project.

Black holes are among the most mysterious objects in the universe, devouring everything within their gravitational reach. They act, in essence, like cosmic vacuum cleaners that can gobble up anything -- including stars, planets and whole galaxies, if they wander too close. Their immense pull is believed responsible for swirling masses of stars that radiate brilliantly across the heavens.

A fuller understanding of black holes is considered essential to comprehending the physics that drives celestial objects, from quasars to galaxies.

The discovery is the most stunning result to date from an extraordinary research tool that went into operation in 1993. The Very Long Baseline Array consists of 10 radio dishes, each 82 feet wide, scattered across the United States. The array acts as a single telescope 5,000 miles wide, yielding a resolution so precise that a user standing in Los Angeles could read a newspaper in New York.

An international team of Japanese and American astronomers made the discovery while studying a galaxy 21 million light years from Earth. The scientists suspected that a black hole lurked at the heart of the galaxy because radiation from that region of the sky indicated that some powerful force was ripping its neighbor apart. As they zeroed in on the suspect, they made a series of startling discoveries.

Captured throughout a thin disk of material swirling around the center of the galaxy were clusters of water molecules that performed a unique service for the astronomers. The water molecules were acting as masers -- the cosmic cousins of earthbound lasers -- capturing and amplifying radiation from the violent activity closer to the center of the galaxy.

The masers beamed intense radiation directly toward the Earth, serving as a series of powerful beacons orbiting the suspected black hole. The masers were found to be traveling at the astonishing speed of 650 miles per second.

Physics dictates that anything moving at such a speed would have to be orbiting around a very massive beast, indeed.

Calculations showed the mass had to be equivalent to 40 million suns, more than 10 times greater than the mass of any other suspected black hole discovered so far.

Astronomers who "want desperately to avoid its being a black hole'' could still argue that a tight cluster of perhaps 100 million or more stars could generate a gravitational field strong enough to cause the signature seen by the series of radio telescopes, Moran said.

However, those stars would have to be so close together that they would probably collide in a stellar catastrophe, he said.