Kendrick Smith

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.

In Chile's Atacama Desert stands a telescope that doesn't look at stars, but at the oldest light in the Universe — the cosmic microwave background. This light has been traveling to us for nearly 14 billion years, ever since the Universe became transparent. On its way, it passed through clouds of hot gas around galaxies.

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.