On Thursday, researchers announced that they’d caught a single, tiny, high-energy particle called a neutrino that had rained down on Earth from a supermassive black hole some 4 billion light-years away.Astrophysicists are excited because this is only the third identified cosmic object they’ve managed to collect the elusive particles from — first the Sun, then a supernova that went off in a neighboring galaxy in 1987, and now a blazar.So, what is a blazar, anyway?At the center of most galaxies — including our own Milky Way — there’s a gargantuan black hole that can have the mass of millions or even billions of Suns. In some galaxies, this supermassive black hole may collect a swirling disk of gas, dust and stellar debris around it to eat from.As material in the disk falls toward the black hole, its gravitational energy can be converted to light, making the centers of these galaxies very bright and giving them the name active galactic nuclei (AGN).Some of these active galactic nuclei also shoot out colossal jets of material that travel close to the speed of light. Scientists call this a quasar.But when a galaxy happens to be oriented so the jets point toward Earth — and we’re staring right down the barrel of the gun, as it were — it’s called a blazar. It's the same thing as a quasar, just pointed at a different angle.Those jets shoot matter at close to the speed of light in our direction and, we now know, produce high-energy neutrinos like the one detected by the IceCube instrument in September 2017.