Researchers just announced the discovery of radio signals from beyond our galaxy that are behaving in strange ways. Fast radio bursts—or FRBs—are very rare, very quick blasts of radio waves originating billions of light years away, Popular Science explains. It's unclear where exactly in the universe they're coming from and what's causing them. Since the first one was discovered in 2007, scientists have found only 17 total, and none of them ever repeat, the Verge reports. At least that's what everyone thought. According to a paper published this week in Nature, researchers at Cornell University have found evidence of FRBs that do just that.
Scientists used to think FRBs were caused by "cataclysmic events," such as neutron stars colliding with each other and exploding. Repeating FRBs means that can't be the case. "This research shows for the first time that there can be multiple FRBs from the same place in the sky," researcher Shami Chatterjee says in a press release. "Whatever produces the FRB can't be destroyed by the burst, because otherwise, what would produce the next pulse?" And the mystery deepens: "We're showing that whatever battery drives FRBs, it can recharge in minutes," astronomy professor James Cordes says. "The energy of the event becomes very problematic." Researchers hope to next pinpoint where the FRBs are coming from in order to figure out what they're coming from, and they'll be helped by three massive radio telescopes that start operating next year. (Speaking of space mysteries: "Alien megastructures" have scientists baffled.)