WASHINGTON A giant hole in the Universe is devoid of galaxies, stars and even lacks dark matter, astronomers said on Thursday.
The team at the University of Minnesota said the void is nearly a billion light-years across and they have no idea why it is there.
"Not only has no one ever found a void this big, but we never even expected to find one this size," said astronomy professor Lawrence Rudnick.
Writing in the Astrophysical Journal, Rudnick and colleagues Shea Brown and Liliya Williams said they were examining a cold spot using the Wilkinson Microwave Anisotropy Probe satellite, and found the giant hole.
"We already knew there was something different about this spot in the sky," Rudnick said. The region stood out as being colder in a survey of the Cosmic Microwave Background -- the faint radio buzz left over from the Big Bang that gave birth to the Universe.
"What we've found is not normal, based on either observational studies or on computer simulations of the large-scale evolution of the Universe," Williams said in a statement.
The astronomers said the region even appeared to lack dark matter, which cannot be seen directly but is usually detected by measuring gravitational forces.
The void is in a region of sky in the constellation Eridanus, southwest of Orion.
The researchers have posted images on the Internet at www.nrao.edu/pr/2007/coldspot/graphics.shtml.