A study using simulations of how cosmic structures form indicates that most galaxies including the Milky Way reside in a great cosmic void that is about 1 billion light-years wide. This cosmic void idea could resolve the puzzlement in gauging how fast the universe is expanding.
The findings of the study were presented at a meeting at the American Astronomical Society in Austin, Texas, on June 7, 2017. It was led by Benjamin Hoscheit, the lead author of the study, and astronomer Amy Barger from the University of Wisconsin-Madison and other colleagues. The team discovered that the void that has the Milky Way is huge, spherical and contains many superclusters.
The idea is that imagine the universe as a block of Swiss cheese, in which it is made up of filaments of matter such as galaxies and stars. The holes in the cheese represent the areas of relative nothingness. The cosmic void that could be a hole is theorized as to be seven times bigger than the average void or about 1 billion light-years across. This means that the Milky Way happens to be in this hole or void as massive as this said measurement, according to Wired.
This void is named KBC void that stands for scientists Keenan, Barger and Cowie. It could be the largest void in the universe. This cosmic void idea could help scientists solve and calculate the expansion rate of the universe.
Hoscheit said that no matter what technique you use, you should get the same value for the expansion rate of the universe today. He further said that living in a void helps resolve this tension.
The void in which the Milky way resides could explain why the universe seems to be expanding at various rates, depending on how it is gauged. The measurements based on the cosmic microwave indicates one rate of expansion. Meanwhile, the measurements of closeby supernovas indicate a rapid one.
Hoscheit said that those supernovas have extra gravitational pull from all the matter at the edges of the void. It is theorized that the actual expansion rate could be the slower one gauged in the universe's early light, as noted by Science News.