Astronomers discover what is causing those mysterious cosmic radio bursts

A long time ago in a galaxy far, far away….

This is not 40-year-old fiction. This is a 3-billion-year-old true story.

Three thousand thousand thousand years ago, give or take a few million years, in a galaxy 3 thousand thousand thousand light years away, give or take a few million light years, a fast radio burst from the center of a dwarf galaxy far beyond the Milky Way generated as much energy as 500 million suns in milliseconds. And then it came out for an encore. And another. It has done roughly 30 curtain calls in all.

This, according to Science Alert, was the amazing discovery of astronomers from McGill University in Canada and Tohoku University in Japan. Working separately with images obtained from the Hubble Space Telescope and the 8.2-meter Subaru Telescope in Hawaii, they believe they have pinpointed the location of the first repeating fast radio burst ever seen in the universe.


Fast radio bursts – FRBs – are hard to detect and even harder to pinpoint, because they last only for milliseconds. But there’s one – and, so far, only one — that has delivered roughly 30 signals from the same location, enabling the astronomers to focus on the spot and study it closely — or as closely as anyone can study something that’s 3 billion light years away.

What they’ve found, in studies that are awaiting peer review, is that FRB 121102, which was originally believed to be emanating from within our Milky Way, is located instead in a giant stellar nursery near the center of a faint dwarf galaxy 3 billion light years away. That means whatever they see happened 3 billion years ago.

"Hubble's handiwork puts the galaxy's visible diameter at about 20,000 light-years, one-sixth that of the Milky Way,” Ken Croswell wrote in New Scientist. “The stellar nursery is 6,200 light years from the galaxy's center and spans 4,400 light years, far larger than any known in the Milky Way."

The scientists say their discovery strengthens the theory that the densest object in the known universe, a magnetar — a highly magnetic, 12-mile-wide neutron star that forms after a star collapses and emits regular radio pulses as it spins — was the cause of the repeating FRB.

But it also creates a new mystery: Why is this FRB repeating when the 22 others that have been observed through history aren’t?

Let’s hope it doesn’t take 3 billion years to find out.