PhysicsWhy is it so difficult to find a viable quantum theory of gravity? The way we calculate the properties of subatomic particles with quantum theory goes haywire when it comes to hypothetical particles of gravity, but there may be a clever workaround Features
PhysicsStates of matter: The unthinkable forms beyond solid, liquid and gas From time crystals to supersolids, we keep discovering extraordinary new kinds of matter – now the true challenge is being able to predict what we'll find next Features