It’s almost the end of the work week, but for some very confused astronomers the weekend is the last thing on their mind. According to Agence France Presse, scientists unveiled the first and only galaxy that exists without dark matter on Wednesday.

For those less scientific folks out there, dark matter is a substance that astronomers are still unable to see, but think makes up much of the known universe. Dark matter is an essential part of the Big Bang Theory, but this discovery could completely undo current theories about how galaxies are created. 

"This is really bizarre," co-author Roberto Abraham, an astronomer at the University of Toronto, told AFP. "For a galaxy this size, it should have 30 times as much dark matter as regular matter. What we found is that there is no dark matter at all. That shouldn't be possible.”

Astronomers estimate that there are 200 billion observable galaxies, filled with dark matter and ordinary matter, classified as stars, gases, dust, planets. "It is conventionally believed to be an integral part of all galaxies, the glue that holds them together and the underlying scaffolding on which they are built," co-author Allison Merritt said of dark matter. Merritt is from the Max Planck Institute for Astronomy in Germany.

But about 65 million light-years from Earth, the galaxy nicknamed "DF2” sits with almost no dark matter at all. "We asked ourselves where we had screwed up, if the measurements were wrong," Abraham said. "Then I suddenly realized the implications. That's as close to an 'oh my God' moment as I got." 

Astronomers now have the task of figuring out how a galaxy without something considered so vital to the makeup of the universe exists. "It challenges the standard ideas of how we think galaxies work," lead author Pieter van Dokkum of Yale University said.