The more astrophysicists study dark matter, the more they realize how much more there is to learn about the subject. Dark matter binds galaxies together in a completely mysterious way, as there seems to be no way of directly observing this peculiar form of matter. In fact, dark matter is much more prevalent throughout the Universe than the type of matter that we’re interacting with every day: about 95% of the Universe’s mass consists of dark matter, while only 5% remains for normal matter.
A team of researchers led by Massimo Meneghetti of the National Institute for Astrophysics in Italy analyzed data provided by the good old Hubble Telescope. They could analyze dark matter by examining the gravitational effects produced by it.
11 galaxy clusters targeted
The scientists examined the amounts of dark matter belonging to 11 large clusters of galaxies. They furtherly generated simulations of the expected lensing effects in the laboratory, as areas that are rich in dark matter show gravitational lensing when light gets close. They compared the simulated outcome to the findings from reality.
Judging by the large scales, the models were matching the reality. But the study also revealed lensing around certain galaxies, something that wasn’t predicted in the model. This is a hint that the amount of dark matter from those galaxies is about 10 times higher than believed.
The velocity of stars confirms the discovery
The next step was for the team to conduct spectroscopic observations for the galaxies that stood out. They could calculate the velocity of stars by observing light shifts. The outcome was that indeed, the amount of dark matter is much higher than expected. One of the ways scientists can measure dark matter is by the precise calculation of the stars’ velocity.
Even though scientists were able to estimate the amount of dark matter from a certain region of space by comparing the predicted gravity from normal matter with the actual observed gravity, humanity still needs to find out what dark matter is made of.