Almost two decades ago, astronomers detected a little “squeak” of radio energy from the stars – a blip that lasted a fraction of second. Since then, hundreds more have been detected. But they’re more than just little squeaks. They’re massive outbursts of energy that can be heard across the universe.

Fast radio bursts last from less than a thousandth of a second to about three seconds. They come from galaxies that are millions or billions of light-years away. At that distance, an outburst of just a thousandth of a second must produce as much energy as the Sun will emit in several years.

Scientists are still trying to figure out the cause of fast radio bursts. Because the bursts are so short, they must come from small, compact sources. Most explanations involve neutron stars – the ultra-dense corpses of once mighty stars.

A neutron star is more massive than the Sun, but no bigger than a small city. That makes it extremely dense, so its gravity is millions of times the strength of Earth’s gravity. So if anything hits a neutron star, it creates a titanic explosion. An asteroid a few miles wide, for example, would explode with the power of billions of hydrogen bombs.

That’s not the only possible explanation, though. Bursts could be caused by disruptions to a neutron star’s powerful magnetic field, by exploding stars, or by something else – outbursts that can be heard across the universe.

Script by Damond Benningfield