Scientists have found more than 800 strange “ultra dark” galaxies in the Coma cluster far away in the Berenice’s Hair constellation, and found that they are huge galaxies that contain just a few stars — meaning that there’s something dark lurking underneath.

U.S. and Japanese astronomers counted 854 of these “UDGs” (ultra dark galaxies) using the Subaru Telescope, a massive 8.2-meter telescope located in Mauna Kea, Hawaii, and owned by the National Astronomical Observatory of Japan, according to a Russia Times report. They will publish their findings today in the Astrophysical Journal Letters by the American Astronomical Society.

These galaxies sit about 300 million light years from our planet, and had until now been unknown because they had not been spotted yet because of their almost total lack of visible light.

These galaxies are huge — close to the size of the Milky Way. The amount of stars they have, however, is not so huge: likely thousands of times less than the stars within our own galaxy, according to the report.

So how is this possible? The galaxies appear to have lost a lot of gas, which is necessary for new stars to form, and the Coma cluster’s environment itself may have caused this to come about, although scientists aren’t really sure.

These “ultra dark” galaxies appear to sit at the heart of the Coma cluster, where the forces of gravity are probably quite intense, so much so that scientists would have expected it would have destroyed the galaxies — and yet here they are. It’s leading scientists to believe that perhaps there’s something mysterious keeping the galaxies from disintegrating.

Jin Koda, the principal investigator of the study who hails from Stony Brook University, said in a Daily Mail report that the galaxies are “likely enveloped by something very massive.”

Dark matter is the most likely candidate, and it may account for more than 99 percent of all mass in the galaxies. The findings could have major implications for astronomy and the alteration of some fundamental theories.