By now, scientists know that galaxies all have some level of dark matter in them, to various extents. Dark matter is an important part in the formation of a galaxy. However, a recent discovery shows that there is one particular galaxy that has almost no dark matter in it. This challenges all the conventional theories that scientists have the importance of the dark matter in a given galaxy.
How is that possible?
For those curious about it, the galaxy is almost 65 million light-years from our own planet and scientists have named it NGC1052-DF2. They classified it as an ultra-diffuse galaxy, since it is incredibly large but it still looks very faint. This means that the galaxy is as big as our Milky Way but it does contain the same amount of stars which makes it less bright. This is not the first faint galaxy out there in space but NGC1052-DF2 is the first galaxy out there to not have dark matter.
The lead author of this study, Pieter van Dokkum, had some things to say about what he and his team of researchers found out. He says that this galaxy challenges the way in which scientists believe that galaxies are formed. It was believed that they all start as blobs of dark matter but it looks like this concept may be challenged by NGC1052-DF2.
This amazing discovery could not have been done by scientists without the help of Hubble. The observations that they could do with Hubble allowed them to calculate the size and the brightness level of the galaxy. Once they calculated the mass of the galaxy they determined that it all comes from the mass of its stars, proving that there is almost no dark matter in the galaxy. The dark matter would have influenced the size of the mass.