Dark matter is (probably) more complex than you think

Scientists typically believe that dark matter behaves in a simple way: if one clump encounters another, the two interact solely through gravity. However, researchers have published findings which suggest that there’s more involved. They’ve noticed dark matter (the blue lines in the photo above) lagging behind a galaxy due to friction, hinting that there are factors beyond gravity at work. It’s not known whether the source of this friction is a familiar phenomenon or something entirely undiscovered, but it’s definitely not the usual culprit.

It’ll be a long while before the answer is found. The findings only touch on one galaxy, and there’s currently an 0.1 percent chance that this is simply an error in measurement. Researchers want higher accuracy before they confirm this to be accurate. If the data is accurate, though, humanity will have a much more detailed sense of what dark matter truly is, and how it affects the cosmos.

[Image credit: ESO/R. Massey]