From the moment it burst into existence more than 13 billion years ago, the universe has been expanding, with galaxies visibly flying apart from each other. To make sense of the physical laws governing the cosmos, astronomers have tried to measure one of the most important numbers in cosmology, the Hubble constant, which describes how quickly this expansion is happening and the universe’s age in turn.

But recently, multiple efforts to find a value for the Hubble constant have turned up a potential crisis in cosmology: the universe seems to be flying apart faster than expected. If confirmed, this baffling change would force astrophysicists to rethink the fundamentals of our universe, which currently don’t provide for such a change even