Astronomers have discovered a billion-light-year-wide hole in the cosmos that’s devoid of stars, galaxies, gas and even dark matter. The presence of empty space out there in the universe isn’t shocking. It’s the unusually large size of the gap that has puzzled scientists.

After initially spotting the void in 2004, the astronomers analyzed data from the Very Large Array radio telescope’s Sky Survey, and found that the gap corresponded to a drop in the number of galaxies in part of the constellation Eridanus. Reporting in the Astrophysical Journal, the group says that the hole’s existence isn’t normal in terms of what we know from computer simulations or observational studies. So we’ll just have to add this to the ever-growing list of what we don’t understand about the universe.—Gregory Mone