Nobody knows what causes fast radio bursts
The core idea stands, but key numbers or details have changed.
TaughtFast radio bursts, millisecond flashes of radio energy that release more power than the Sun does in days, were one of astronomy's great open mysteries. Every one had come from a distant galaxy, too far to trace to any particular object, and their source was genuinely unknown.
NowOn 28 April 2020, telescopes caught a fast radio burst coming from inside our own galaxy, from SGR 1935+2154, a magnetar about 30,000 light-years away. It was the first FRB ever tied to a known object, showing that at least some of these bursts are flares from the crushingly strong magnetic fields of dead stars.
What actually happened
A magnetar is the collapsed core of a dead star with a magnetic field trillions of times stronger than Earth's. Two teams, the CHIME array and the STARE2 detectors, independently caught the burst and pinned it to the same magnetar, publishing together in Nature in November 2020.
The honest hedge: this doesn't close the case entirely. The galactic burst was less energetic than the distant ones, and astronomers still suspect fast radio bursts may have more than one kind of source. So this is 'updated,' not 'solved.'
But the flat old statement, that we had no idea what produces a fast radio burst, moved. For the first time we had one culprit, caught in the act, in our own galaxy.
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Who was taught this
Still standard through 2020, so anyone who finished school between 1950 and 2020 learned the earlier version.