On 12 November 2025, LIGO picked up a gravitational wave signal that stopped astronomers in their tracks. The object that produced it was too small to be any known type of black hole, smaller in fact, than our own Sun. If confirmed, it would be something that has never been directly detected before, a primordial black hole forged in the violent chaos of the first fraction of a second after the Big Bang. Now two astrophysicists believe they can explain exactly what LIGO found and why it could crack open one of the deepest mysteries in cosmology.