Imagine an especially hole-y block of Swiss cheese, and you have a pretty good visual for the leading theory for the structure of the universe. Voids, vast expanses of nearly empty space, account for about 80 percent of the observable universe. The other stuff, like dust and stars and galaxies like the Milky Way, exists in thread-like filaments between these voids. As the universe expanded, gravity drew matter into clumps, leaving behind cavernous spheres. These empty regions, which can measure hundreds of millions of light years across, do contain some galaxies, but they’re dark caverns compared to the dense, bright bands of millions of galaxies ringing their edges.
According to researchers at the University of Wisconsin-Madison, our very own Milky Way galaxy may float near the center of one of these voids.
Using data from large-scale telescope surveys that count galaxies, the researchers concluded that the Milky Way exists near the center of a region that has fewer galaxies than other parts of the universe. They estimated the size of this void to have a radius of about 1 billion light-years. If they’re right, humans are living in the middle of the largest known void in the observable universe.