An odd solid that can flow like a fluid has been created from light for the first time. Studying it will help researchers better understand exotic quantum states of matter.

“We actually made light into a solid. That’s pretty awesome,” says Dimitris Trypogeorgos at the National Research Council (CNR) in Italy. He notes Daniele Sanvitto, also at CNR, showed how light could become a fluid more than a decade ago. Now Trypogeorgos, Sanvitto and their colleagues have used light to make not just any solid, but a quantum “supersolid”.