Black holes have nothing on black void in universe

Last update: August 23, 2007 - 9:07 PM

WASHINGTON - Astronomers have stumbled upon a tremendous hole in the universe that's got them scratching their heads about what's just not there.

The cosmic blank spot has no stray stars, no galaxies, no black holes, not even dark matter. It is 1 billion light years across of nothing. That's an expanse of nearly 6 billion trillion miles of emptiness, a University of Minnesota team announced Thursday.

Astronomers have known for many years that there are patches in the universe where nobody's home. One such place is practically a neighbor, a mere 2 million light years away.

But what the Minnesota team discovered is a void that's far bigger than ever imagined.

"This is 1,000 times the volume of what we sort of expected to see in terms of a typical void," said Minnesota astronomy Prof. Lawrence Rudnick, author of the paper to be published in Astrophysical Journal. "It's not clear that we have the right word yet. ... This is too much of a surprise."

Rudnick was examining a sky survey from the National Radio Astronomy Observatory, which essentially takes radio pictures of the universe. Those pictures indicated one area of the universe had up to 45 percent less matter, Rudnick said. The rest of the matter can be explained as stars and other cosmic structures between here and the void, which is about 5 to 10 billion light years away.

Rudnick then checked observations of cosmic microwave background radiation and found a cold spot. The only explanation, Rudnick said, is it's empty of matter.

"It looks like something to be taken seriously," said Brent Tully, a University of Hawaii astronomer who wasn't part of the research.

ASSOCIATED PRESS