A tremendous blank spot free of galaxies, stars, dark matter or black holes has been discovered in the distant reaches of space.
Astronomers at the University of Minnesota have located a gigantic hole in the universe. This empty space, stretching nearly a billion light-years across, is devoid of any matter such as galaxies, stars, and gas, and neither does it contain the strange and mysterious dark matter, which can be detected but not seen.
Prevalence of Holes
Empty places in the universe are not uncommon. It is already known that matter tends to clump and form stars and galaxies, clusters and superclusters, due to the pulling force of gravity. So astronomers have already seen places in the universe where there are groups of matter and places where matter is more scarce. But this new discovery is much larger than any previously known "hole".
“Not only has no one ever found a void this big, but we never even expected to find one this size,” explains Lawrence Rudnick of the University of Minnesota. Rudnick was one of the researchers to find the hole. The news was reported in the Astrophysical Journal.
Source of Discovery
Rudnick and his team studied data from a survey of the entire sky imaged by the Very Large Array radio telescope. A map of this area of the sky was already known to be an anomaly. It had been called a "cold spot" after a satellite that charts the cosmic microwave background radiation discovered it was less warm than its surroundings. (Overall the cosmic microwave background radiation is exceptionally cold, and the difference seen was only in millionths of a degree.)
The area of sky in which the hole exists lies in the direction of the constellation Eridanus. Eridanus is the constellation of the River, and can be found winding below Taurus and Cetus.
Where the Hole Lies
But the hole is not a part of the cosmic microwave background (CMB) radiation, which is a remnant of the Big Bang. The hole lies between six to 10 billion light-years away. The cold spot is a result of the CMB radition passing through this blank area on its way to Earth. The region is colder because of dark energy.
Dark energy can be seen as the opposite of gravity. While gravity pulls matter together, dark energy is what is causing the universe to expand, and at an ever-increasing rate. When the radiation from the Big Bang passed through this void in the universe, it had less energy than the radiation that passed through normal regions of space. In a simplistic explanation, the radiation is given a boost when it nears the pull of matter such as galaxies, and dark energy allows the radiation to propel away from these areas without losing the boost when gravity would pull it back. The radiation passing through the empty space does not get the boost and the energy, therefore it is slightly colder.
