Like a "sharing bag" of crisps, the Southern Local Supervoid is very large but disappointingly empty. It lies next to the Local Supercluster, some 3 billion light-years from our own Sun, and is 112 megaparsecs in diameter across its narrowest width. Picture the Milky Way galaxy, then multiply it 600 billion times: that’s roughly the size of this vast patch of space. Colossal, yet deserted. But why?

According to astronomers, superclusters of galaxies tend to collapse and recollapse onto themselves, while voids tend to grow. The less dense the area, the more it will expand. And the Southern Local Supervoid isn’t even the biggest void out there. In the list of the largest voids, the SLS is only 61 of 113.