Neutron stars in the universe, ultracold atomic gases in the laboratory, and the quark–gluon plasma created in collisions of atomic nuclei at the Large Hadron Collider (LHC): they may seem totally unrelated but, surprisingly enough, they have something in common. They are all a fluid-like state of matter made up of strongly interacting particles. Insights into the properties and behavior of any of these almost-perfect liquids may be key to understanding nature across scales that are orders of magnitude apart.