We thought we were finally getting a basic understanding of Fast Radio Bursts (FRBs) as rare and one-off events, and then Mother Nature decides to throw us a curve ball and hit us with the first repeating FRB.

The source, FRB 121102, was discovered first in 2012. Last year, an international team of researchers used the Arecibo Observatory radio telescope to look at the same region and they were surprised to find 10 additional bursts. As cataclysmic events don’t repeat themselves, the team believes that these bursts were produced by a highly magnetized, extragalactic neutron star.

FRBs were only discovered about a decade ago, and there are only a handful of known examples. These phenomena are isolated and rare, making it very difficult for scientists to understand their causes. The emission regions are estimated to be just a few hundred kilometers across, and it is thought that these signals are from another galaxy. These two qualities indicate that whatever is behind these events must be very bright.

Hypernovae and colliding binary neutron stars, or even black holes, have all been proposed as potential explanations. These events are all incredibly powerful but they would be a one-off occurrence, not a multiple-burst event like the one observed.

"Not only did these bursts repeat, but their brightness and spectra also differ from those of other FRBs," notes Laura Spitler, first author of the new paper, in a statement.

The research, published in Nature, comes in a big week for FRBs. Last week it was announced that scientists had pinpointed the location of an FRB for the first time, but now that claim is being questioned. Being able to pinpoint the exact location is paramount to understanding better these astrophysical events. To find the exact location of this unusual burst event, scientists will need to study the source in more detail.

"Once we have precisely localized the repeater's position on the sky, we will be able to compare observations from optical and X-ray telescopes and see if there is a galaxy there," says Jason Hessels, associate professor at the University of Amsterdam and the Netherlands Institute for Radio Astronomy. "Finding the host galaxy of this source is critical to understanding its properties."