The supermassive black hole at the centre of our galaxy, the Milky Way, is flickering - we know that thanks to observations taken in the past few years with the James Webb Space Telescope, JWST, which were published this month by Yusef-Zadeh and collaborators.
Now just to be clear what’s been detected is not light from the black hole itself, because black holes are so dense and their gravity is so strong that not even light can escape from them. The light that has been detected is from the region around the black hole, what’ known as the accretion disk, a swirling, glowing, maelstrom of material orbiting the black hole which will eventually fall beyond the event horizon and add to the black hole’s mass.
This material is accelerated to such huge speeds that it glows, so by studying that glow we can work out what is going on in in those turbulent regions around the black hole, we can study how our supermassive black hole is growing - is it smooth growth, or is there a lot of turbulence which causes the light we receive to vary and flicker?
But JWST also spotted some bright flares from our supermassive black hole, so what's causing those?