Astronomers have discovered the largest structure in the found in the universe to date. The so-called “super void” is a empty patch or a cold spot 1.8 billion light years across.

While it is called a “hole” in space it is not as empty as it sounds. The super-void isn’t empty, it is only about 20 percent less full than it should be. While that may not sound like anything to get excited about, in an area that big it means that about 10,000 galaxies that should be there aren’t.

It also raises some interesting questions about what happened in the early universe, shortly after the big bang, to create such a large void.

The cold spot was originally detected in 2004 by astronomers who were studying a map of radiation left over from the Big Bang, otherwise known as cosmic microwave background (CMB).

The physics of the Big Bang allow for warmer and cooler spots in the universe, no explosion is completely uniform, however a spherical void of this size and magnitude caught researchers completely by surprise.

If the unusual cold spot was created by or shortly after the big bang, it would suggest exotic physics not accounted for by current theories. On the other hand, if it was not caused by the big bang it would mean an “extremely rare large-scale structure in the mass distribution of the universe,” according to a statement.

Recently, a team of astronauts led by Dr. Istvan Szapudi of the Institute for Astronomy at the University of Hawaii at Manoa conducted a detailed study of the cold spot. The team used data from NASA’s Wide Field Survey Explorer (WISE) satellite as well as Hawaii’s Pan-STARRS1 (PS1) telescope.

The team discovered the 1.8 billion light-year wide super void by combining the PS1 data with infrared data from WISE to find the position of and distance to each galaxy in the void.

According to the researchers, mapping large structures nearby is more difficult than finding distant ones because mapping closer ones requires the observation of larger portions of the sky.

The super void is about 3 billion light years from Earth, which makes it very close in cosmic terms. Dr. András Kovács of Eötvös Loránd University in Budapest, Hungary used the WISE and PS1 data to create 3D maps which were essential for identifying the super void.

Because the void is so large, and the universe is expanding light entering the void takes a long time to move across it and loses energy in the process, the researchers believe that this discovery could help to explain anomalies found in the CMB.

“Imagine there is a huge void with very little matter between you (the observer) and the CMB. Now think of the void as a hill. As the light enters the void, it must climb this hill. If the universe were not undergoing accelerating expansion, then the void would not evolve significantly, and light would descend the hill and regain the energy it lost as it exits the void. But with the accelerating expansion, the hill is measurably stretched as the light is traveling over it. By the time the light descends the hill, the hill has gotten flatter than when the light entered, so the light cannot pick up all the energy it lost upon entering the void. The light exits the void with less energy, and therefore at a longer wavelength, which corresponds to a colder temperature,” according to the team.

The complete results of the research by Szapudi, Kovács and their associates can be found in the Monthly Notices of the Royal Astronomical Society.