Gigantic Empty Space in Universe Discovered

It’s understandable when astronomers get excited about discovering, say, an extrasolar planet. But it’s also a big deal when they find nothing — that is, a mind-bogglingly huge expanse of space, some 1 billion light-years across, that contains no galaxies or black holes or even that ominous-sounding dark matter.

"Not only has no one ever found a void this big, but we never even expected to find one this size," explains University of Minnesota astronomy professor Lawrence Rudnick, who along with colleagues Shea Brown and Liliya R. Williams reported the discovery in a scientific paper accepted for publication in the Astrophysical Journal.

The astronomers discovered the empty region while examining data from a sky survey carried out by the Very Large Array radio telescope, part of the National Radio Astronomy Laboratory.

"One morning I was a little bored, and said, 'Why don’t I look in the direction of the WMAP [Wilkinson Microwave Anisotropy Probe] cold spot?’" Rudnick recounted for New Scientist.

The cold spot was a mysterious area that stood out in a map of cosmic microwave background radiation made by a NASA satellite in 2001. CMB remains from the "Big Bang" that created the cosmos, and the astronomers wondered if the irregularity in the CMB map might reveal some structure from the universe’s infancy. (Another possibility was that the radio waves were being blocked by a celestial object closer to Earth.)

Instead, the astronomers found, the slightly colder temperature of the CMB in the region was caused by a massive expanse of emptiness located some 6 to 10 billion light-years from Earth.

Though other empty spaces in the universe have been discovered, this one is about 1,000 times larger than what astronomers would have expected.

"In our own Milky Way Galaxy, we have 100 billion stars," Rudnick explained to the Minneapolis Star-Tribune. "If we were to go off in a spaceship … traveling at the speed of light, you would only have to go a few years before you find another star … what we found is a place where you'd travel for a billion years before you found another concentration of mass. It would be a very boring journey of a billion years."

The discovery could shed light on how the universe took shape. "It is … part of the story of how we got here," Rudnick told the Star-Tribune.

From NRAO, here’s a graphic that depicts the cold spot. From the Google Earth Community discussion board, here are directions on how you can view the location in the sky.