Another day, another physics-defying discovery. A team of North American astronomers has detected the very first galaxy that seems to contain no dark matter, the invisible and mysterious material that scientists believe makes up more than a quarter of the universe. This unprecedented galaxy has been named NGC 1052-DF2, and it has torn a gaping hole in how astronomers fundamentally understand the formation of galaxies.
This celestial formation, located 65 million light-years away, was spotted by Yale University researcher Pieter van Dokkum and his team. They used a custom-built telescope specially designed to pinpoint faint and scattered galaxies, known as the Dragonfly Telephoto Array. In a paper published in the journal Nature, the astronomers explain this star system should not be able to hold itself together without the help of dark matter. In other words, based on how we understand the physics of the universe, NGC 1052-DF2 should not exist.
“This is really bizarre,” Van Dokkum tells AFP News. “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.” Join our private Dope Space Pics group on Facebook for more strange wonder.
This large, fuzzy-looking galaxy is so diffuse that astronomers call it a “see-through” galaxy because they can clearly see distant galaxies behind it. The ghostly object, catalogued as NGC 1052-DF2, doesn’t have a noticeable central region, or even spiral arms and a disk, typical features of a spiral galaxy. But it doesn’t look like an elliptical galaxy, either. Even its globular clusters are oddballs: they are twice as large as typical stellar groupings seen in other galaxies. All of these oddities pale in comparison to the weirdest aspect of this galaxy: NGC 1052-DF2 is missing most, if not all, of its dark matter.
Dark matter is impossible to observe directly because it doesn’t emit light or energy, so astronomers identify traces of it by observing how it interacts with visible matter through gravity. Some of the best evidence of dark matter comes from stars that appear to be orbiting their galaxies faster than their escape velocity — or the speed at which objects are supposed to break free of the gravitational bonds holding them in place. This alludes to the fact that there’s something that we can’t see keeping everything together.
This is all still theoretical, but Van Dokkum and his colleagues have set their sights on figuring out how NGC 1052-DF2 is being held together and how it even formed in the first place. This is a task that might possibly require a whole new outlook on astrophysics.
And just like that, a singular picture of the cosmos can rewrite physics textbooks around the world.
