What the hell is a fast radio burst? They could help teach us how the universe began. They could be concrete proof that intelligent extraterrestrials exist. Or, as some new research seems to suggest, they might be — in blunt terms — stars made of dark matter slamming into black holes.
That unholy trinity of astrophysical calamity needs some unpacking, so listen closely. Aiichi Iwazaki, an astronomer at Nishogakusha University in Tokyo, believes, subscribes to the theory that dark matter — the mysterious stuff that makes up about 85 percent of the universe, but which humans have never directly observed — is made of theoretical particles called axions. If axions are real, they would be very light and long-lived particles that only interact with matter in very weak ways, such as through gravity. (The reason scientists know dark matter is real is based on the observed movements of stars and galaxies throughout the universe, which can only be explained by — you guessed it — the gravitational effects of dark matter/).
If axions are real, Iwazaki thinks the early universe was small enough for the chances of these particles to clump up into star-like bodies. These would basically be dark matter stars, and they’d probably sit close to the center of galaxies, where supermassive black holes reside. This proximity means the chances of a dark matter star crashing into a black hole would be pretty good.
And the ingredients of such a weird mixture of cosmic phenomena might, according to what Iwazaki tells New Scientist, something like this: the magnetic of the accretion disk surrounding the black hole would cause axions to decay into photons which may be what scientists on Earth have observed as FRBs — low energy radio wavelengths.
This could account for why some FRBs seems to repeat at strange, random pulses, because the dark matter star blowing through the accretion disk would do so over and over, and irregular intervals, until the star was no longer a clump of axions.
It’s a strange idea, but, like many ideas that permeate the world of astrophysics, it’s just a theory. Iwazaki’s idea puts forth an explanation for both dark matter and FRBs, but neither can be proven so far with the type of data scientists have.
If we can one day prove it’s true, however, it would be one hell of an explanation for two of astrophysics biggest mysteries.