Astronomers say they've identified a "supermassive" black hole with a diameter 20 times that of the sun at the center of the Milky Way galaxy. (see also http://www.physorg.com/news7831.html)

Chinese astronomer Shen Zhiqing and his team of four U.S.-based researchers say they have the first concrete proof of a black hole, the Shanghai Daily reported Wednesday.

"We have finally revealed concrete evidence of a black hole that astronomers have sought for years," said Shen, a researcher at the Shanghai Astronomical Observatory.

Black holes are collapsed stars with a mass so dense that nothing, not even light, can escape their powerful gravitational pull.

"We're getting tantalizingly close to being able to see an unmistakable signature that would provide the first concrete proof of a supermassive black hole at a galaxy's center," Shen said in a news release. He said he believes the black hole has a mass four million times that of the sun.

He and colleagues, including Fred Lo, director of the U.S. National Radio Astronomical Observatory, have spent eight years, using a U.S. network of radio telescopes to study the black hole.

They report their findings in the current issue of the journal Nature.

Copyright 2005 by United Press International