According to the leading model of the universe, the cosmos is filled with five times more "dark matter" than regular matter. This hypothetical substance is invisible but a dark matter halo is thought to exist around galaxies due to the strong gravitational pull its mass exerts on them. However, not all astronomers agree that dark matter is the best explanation for what we are seeing out there. Now, a new study challenges our current understanding: the dwarf galaxies in the Fornax Cluster don't seem to be following the rules.
The Fornax Cluster is the second closest galaxy cluster to our own. It is located 62 million light-years away and it has an estimated mass of 70 trillion suns. A fair bit of that mass is distributed in dwarf galaxies. In the Monthly Notices of the Royal Astronomical Society, the team set out to test the standard model of cosmology, also known as CDM (lambda-CDM) by looking at these dwarf galaxies and found something surprising. They appeared to have undergone disturbances that would not be possible if they were indeed surrounded by a heavy dark matter halo, as theorized by the standard model.