Paul Scholz

In 1936, two physicists, Werner Heisenberg and Hans Euler, poring over the equations of quantum electrodynamics, found something strange. In a sufficiently strong magnetic field, vacuum should cease to be empty.

Fast radio bursts are instantaneous radio flashes from deep space. In a thousandth of a second they release as much energy as the Sun emits in a month. One such burst, repeating, allowed scientists to peer into the epicenter of a recent stellar explosion.

The night sky looks smooth, but it's actually clumpy — vast communities of galaxies that bend light from distant objects like lenses. When a short, powerful radio burst goes off somewhere in the universe, its path to an Earth telescope can pass near such a clump.

Picture a lighthouse on the shore at night. Its lamp is off almost all the time, but once every few days, for a split second, it blazes so brightly that the light is visible beyond the horizon.