The merger of two neutron stars or a neutron star and a black hole produce gigantic explosions of mostly heavy elements, emitting gamma-ray bursts and ejecting bright electromagnetic radiation in all directions. When two neutron stars collide, the phenomenon is referred to as a kilonova. What is special about these explosions is that when neutron stars collide, they produce an explosion that, contrary to what was believed until recently, is shaped like a perfect sphere. This discovery was made by astrophysicists from the University of Copenhagen. How this is possible is still a mystery, but the discovery may provide some new key insights into fundamental physics.