An interstellar signal? Fast radio bursts are reaching Earth every 16 days, and astronomers are flummoxed.

Have you ever tried to meet up with someone at a stadium, and they're saving your seat but you aren't sure where, and they're trying to wave you down and flash their phone flashlight at you? That's happening right now on a cosmic scale, from 500 million light-years away—except we don't know the source.

A mysterious object from deep space is transmitting radio signals in a repeating 16-day pattern, as published in the recent study (pdf). This sort of signal isn't new, but this is the first time scientists have seen a pattern since the discovery of these celestial yawps.

Mixed signals.

In 2007, humans looked out into the galaxy and were like, "what?" From deep space, superfast radio waves lashed out over the earth in a quick little burst, kind of like a cute alien winking at us from across the galaxian bar (and just as fleeting). Then there were 17 more seemingly-random signals in the coming years. Scientists started calling them fast radio bursts or FRBs, and Earth was pretty much clueless as to whence they came.

Until 2015. The year that Hamilton and Jon Snow died, multiple FRBs flashed at the same location. This allowed scientists to dial in on what it was. If it was repeating, then it wouldn't be an explosion or anything that consumed the source ... But the FRBs came and went, so astronomers grumbled and muttered "neutron stars" under their breath.

Now in 2020, Jon Snow is alive, Game of Thrones is dead, and FRBs are playing precise peekaboo.

The Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst Project (or if you insist on saying it in one breath, CHIME/FRB) spotted the strangest of FRBs. For four days, it sent out consistent radio bursts, and then for 12 days it would stop. Between September 2018 and October 2019 they watched it repeat 28 of these cycles like clockwork. They grew attached to the little twinkle and succinctly (and affectionately!) named it "FRB 180916.J0158+65" in their published study.

"We conclude that this is the first detected periodicity of any kind in an FRB source," said the study's authors.

What's better, this same FRB is the closest one ever detected! Scientists have pinned down the source of the repeating FRB: a spiral galaxy half a billion lightyears away poetically called SDSS J015800.28+654253.0. (For those following along at home, that's FRB 180916.J0158+65 emanating from SDSS J015800.28+654253.0.)

What's causing it?

One theory is that the FRB-causing object could be orbiting a black hole and sending out its signal on each go-around. Another study (pdf) suggests it might be a binary star system, with one of the two suns blowing us a kiss as it dances around its denser partner. It seems like none of the scientists think it's aliens, but one can hope.

tatooine

Sunset of binary stars over Tatooine, courtesy of starwars.com

What do you think causes FRBs? What makes this recent one repeat so exactly? And does it have anything to do with Jon Snow being a Targaryen?

"Chime" in with a comment below!