Black holes are known to be formidable opponents, given the fact that they destroy everything in their path and are unforgiving and inescapable. Their immense gravitational pull alone is insurmountably powerful. When you pair that with the physical phenomena taking place near the event horizon, the combination is unlike even the most powerful force of nature on Earth.
We still don't know exactly what goes on from beyond the point of no return (as they say, "whatever happens in a black hole stays in a black hole." Literally). Now, an elite team of researchers from all across the globe have announced the discovery of lightning. Not ordinary lightning, obviously, but lightning streaming from a supermassive black hole in a distant galaxy.
Dubbed IC 310, this object of interest is a radio galaxy positioned within the Perseus constellation (about 250 million light-years from our neck of the woods). Like pretty much all massive galaxies, astronomers believe this galaxy holds a heavy weight black hole within its core, one that extends 3 AU (three Earth-Sun distances), or 450 million kilometers (it would take light nearly 25 minutes to travel from one side of the black hole to the other).
Evidence supporting the existence of this lightning includes a steady stream of x-ray emission, and a number of strong gamma-ray eruptions.
Back in 2009, one such gamma-ray event happened, which was picked up by MAGIC Telescope (located on La Palma island), with followup observations carried out by the European VLBI Network (EVN). Researchers subsequently learned that the emission — which, according to the team, "is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet" — varied drastically on five-minute time scales.
Generally, these outbursts happen when the black hole sucks in incoming matter, like stars or gas clouds. Huge flashes of light (and, of course, corresponding x-rays) are light-posts, unleashing radiation that can be picked up in different parts of the electromagnetic spectrum. More impressive are the jets that are known to emerge; they spit out beams of light that travel at relativistic speeds, and can be resolved using sophisticated radio tools, like those at the Department of Astronomy and Astrophysics and the Astronomic Observatory of the Universitat de València
Astonishingly, their observations show that the variations in the black hole's radiation output are more extreme than ever thought possible. Moreover, as Eduardo Ros, researcher from the Max Planck Institute for Radio Astronomy and the Universitat de València (and the co-author of the project), explains, the region from which the gamma-rays emerged "has to be lower, even more than the event horizon in the black hole" itself. To them, this also suggests they've seen more of IC 310 than just its central black hole.
More specifically, they believe that the black hole lurking in the galaxy's core must have an exceptionally fast rotational rate, with a stronger-than-usual magnetic field to boot. Furthermore, as the team notes, "We believe that in the black hole's polar regions, there are huge electric fields, which are able to accelerate fundamental particles at relativist speeds, in a way that when they interact with others of lower energy, they are able to produce highly energized gamma rays," argues Ros. He also adds that "We can imagine this process as a fierce electrical thunderstorm."
Further feeding the fire is the fact that our solar system is frequently affected by similar electrical discharges, "Hence, it is possible for the particles to shoot at speeds close to that of light, within the jet, where they will be accelerated, stopped, reaccelerated and finally centrifuged over the limits of the galaxy itself."
Finally, Ros concludes by saying that black holes are normally imaged by high-energy observatories and at interferometry VLBI networks, thus they were able to obtain "unique information on the regions close to the black hole. MAGIC's and EVN's observations point towards the mechanisms that form jets in the immediate environment of the black holes."
Their findings have been published in the journal "Science."