The formation of cosmic structure, on both large scales and small scales, is highly dependent on how dark matter and normal matter interact. Despite the indirect evidence for dark matter, we’d love to be able to detect it directly, which is something that can only happen if there’s a non-zero cross-section between normal matter and dark matter. The structures that arise, however, including galaxy clusters and larger-scale filaments, are undisputed. (ILLUSTRIS COLLABORATION / ILLUSTRIS SIMULATION)
Whatever’s lurking out there, it isn’t all, or even mostly, normal matter.
When it comes to the Universe, it’s only natural to wonder what, exactly, it is that makes everything up. While some of it is matter like us — things assembled out of atoms, which in turn themselves are made of subatomic…
