It’s commonly known amongst astronomers, if not so much amongst the general public, that if you head outside and look up at the constellation of Sagittarius, you’ll be directly facing a vast black hole, millions of times more massive than the Sun. This beast dwells at the very core of the Milky Way galaxy, stirring up all the material for light years around and devouring anything that approaches too directly. It’s hard to see because there are such vast clouds of dust and gas in the way, but a team of European Space Observatory (ESO) astronomers observing patiently with sophisticated infra-red cameras managed to photograph a handful of stars following extremely tight, fast orbits around an empty space. Since only a super-massive black hole could whip entire stars around in such rapid, violent orbits, that was proof that the monster was real, and at home in our galaxy.
Now they’re watching a gigantic cloud of gas fall in to this same space. It is headed almost directly towards the black hole itself, and the immense gravity is accelerating it to enormous speeds: currently at a distance of less than 36 light hours (forty trillion kilometers) away, it is falling at more than eight million km/h. It will collide sometime in mid-2013, but it is already close enough for tidal forces to begin stretching and twisting the cloud out and wrapping it into a disc around the black hole. As it gets closer, and the tides flex it more violently, the gas will begin compressing and churning, getting hotter and hotter. In the final days, it will be so hot that it glows intensely in ultraviolet light, beaming out radiation in all directions. Even though a black hole can never be seen directly, these displays from the tortured matter falling into it shine like beacons. And astronomers will be watching, recording, and measuring.