The galaxy is about 65 million light-years away in the constellation of Cetus and is about the same size as the Milky Way.
A distant galaxy that appears completely devoid of dark matter has baffled astronomers and deepened the mystery of the universe's most elusive substance. Alternatively, the nearby massive elliptical galaxy NGC 1052 may have played a role in NGC1052-DF2's lack of dark matter billions of years ago when it was undergoing the early and violent stages of evolution. However you wouldn't expect that galaxy to be as big as this object (it's nearly the size of the Milky Way), and you'd also expect to see some other remnants around from the merger event.
Even though the galaxy is mostly empty, they found clusters of densely grouped stars. But those alternative theories require stars in this galaxy to zip at least twice as fast as they were seen moving in this study.
Galaxies about the size of our Milky Way are thought to have around 30 times more dark matter than normal matter (that is, all the stuff that we can see, from stars and supernovas to planets and moons). Based on these indirect observations, researchers have estimated that dark matter makes up about 27 percent of our universe.
In other words, the question arises: if a galaxy did not start from dark matter, which then gravitationally attracted common matter, how did it form? "So finding the opposite, namely an absence of dark matter, really came out of the blue for us", he said.
Van Dokkum and his team spotted the galaxy with the Dragonfly Telephoto Array, a custom-built telescope in New Mexico they created to find these ghostly galaxies. Scientists can see right through it like a phantom floating over a bed in a haunted house.
"It's not just galaxies", explains van Dokkum.
"For those kinds of theories, it wouldn't be possible to ever have a galaxy that looks as though it doesn't have dark matter", Jocelyn Monroe, a particle physicist and dark matter expert at Royal Holloway, University of London, who was not involved in the study, told The Verge. Yet in this odd galaxy, the projected signatures of these exotic effects are not seen. There will be a time when the light from those departing galaxies with not be able to cross the space generated by dark energy.
Van Dokkum and colleagues have additional ideas. The next step is to find other galaxies, make the same measurements and see what turns up. Using information from the Keck telescopes, the team found the globular clusters were moving much more slowly than expected. The visible matter accounted for almost all of the total mass of the galaxy, which had never been seen before.
"Every galaxy we knew about before has dark matter, and they all fall in familiar categories like spiral or elliptical galaxies", van Dokkum said.
More work has to be done by the team which is conducting this research and after that, the actual occurrence of the galaxy and the non-occurrence of the dark matter will be proved.
Van Dokkum and his team plan to keep searching for similar galaxies-or just any other weird thing that challenges the current understanding of dark matter. Perhaps it formed from the gases swept up by quasar winds. "The entire fabric of the universe is really the scaffolding of dark matter and everything else is pasted on it". "So then, if you find a galaxy that appears not to have dark matter, you have to ask, 'How was it formed?'" The information on the 10 globular collections the group tracked revealed them relocating far more gradually compared to would certainly be anticipated.