Researchers liken the structure of the universe to Swiss cheese, with holes representing portions of the cosmos where ordinary matter is sparse. A new study suggests the Milky Way exists within an especially large hole. Photo by Millennium Simulation Project
June 6 (UPI) -- Our galaxy and its neighbors exist in a sort of cosmic void, research suggests. The latest analysis supports the conclusion of a 2013 study which showed the Milky Way exists in a region of the universe sparsely populated by galaxies, stars and planets.
The new research -- presented this week at the annual American Astronomical Society meeting -- also helps bridge the divide between astronomers torn by competing measurements of the Hubble Constant, the rate at which the universe is expanding.
Different groups of astronomers have developed different techniques for measuring the Hubble Constant, with each method yielding different numbers.
"No matter what technique you use, you should get the same value for the expansion rate of the universe today," Ben Hoscheit, a grad student at the University of Wisconsin, said in a news release. "Fortunately, living in a void helps resolve this tension."
Because one of the two techniques relies on analysis of nearby supernovae, the fact that our galactic neighbors exist in a void is relevant to the math.
Astronomers liken the structure of the universe to Swiss cheese, filled with holes where ordinary matter is scant. The hole in which the Milky Way resides stretches roughly 1 billion light-years across -- seven times bigger than the cosmos' average void.
Because the second method for calculating the Hubble Constant uses the cosmic microwave background as a guide -- the leftover energy from Big Bang -- the arithmetic is unaffected by the cosmic density irregularities.
"It is often really hard to find consistent solutions between many different observations," said Wisconsin astronomer Amy Barger, who first hypothesized that the Milky Way is in an unusually large void. "What Ben has shown is that the density profile that Keenan measured is consistent with cosmological observable. One always wants to find consistency, or else there is a problem somewhere that needs to be resolved."
