Dark matter is without a doubt one of the most mysterious things out there in the Cosmos, and scientists are only beginning to understand it. It makes up 85% of all the total matter of the Universe, and scientists also believe that it plays a major role in the total energy density of our nature.
Thus, you would expect dark matter to be found pretty much anywhere in the Universe. Yet again, astronomers are finding whole galaxies that lack the mysterious form of matter.
19 more added to the list
Astronomers recently found not one, not two, not three, but an outstanding number of 19 other galaxies that do not have any dark matter in their composition. Qi Guo from the Chinese Academy of Science and her team of researchers found the galaxies while they have been exploring the nature of 324 dwarf galaxies. They used data from the Arecibo Observatory in Puerto Rico and also from the Sloan Digital Sky Survey.
Instead of dark matter, the newfound galaxies are composed of the usual type of matter that we are all familiar with – the one made of protons, neutrons, and electrons.
Lead author Qi Guo of the stated:
This result is very hard to explain using the standard galaxy formation model, and thus encourages people to revisit the nature of dark matter.
van Dokkum, a professor and chair of the Astronomy Department at Yale University, confirmed for us in a press release that scientists initially thought that any galaxy contains dark matter. Also, they thought that any galaxy begins to form with the direct help of dark matter.
Therefore, you can imagine how stunned the scientific community was when they found out that a galaxy without dark matter in its composition can actually exist.
Mr. van Dokkum continues by saying:
This invisible, mysterious substance is the most dominant aspect of any galaxy. So finding a galaxy without it is unexpected. It challenges the standard ideas of how we think galaxies work, and it shows that dark matter is real: it has its own separate existence apart from other components of galaxies.
The new outcome has been published on November 26 in Nature Astronomy.