In what has truly turned out to be a momentous occasion in astrophysics, today scientists announced the first-ever direct observation of gravitational waves by the Laser Interferometer Gravitational-wave Observatory (LIGO) experiment, which consists of two enormous detector facilities located in Louisiana and Washington state and an international consortium of thousands of researchers.
First predicted by Albert Einstein in 1915, gravitational waves are the “ripples” in the fabric of space-time created by exceptionally turbulent and powerful cosmic events. Physicists have accepted their existence for decades and in recent years have even observed their effects, but only with the incredible sensitivity of the NSF-funded advanced LIGO instrument has their direct detection been made possible.
“This was truly a scientific moon shot, and we did it. We landed on the moon.”
– David Reitze, Executive Director of LIGO
While what exactly goes on within the event horizon of a black hole is still well within the realm of theoretical physics (and it’s said that at the very heart of a black hole physics as we know it gets a serious kick in the pants) researchers are learning more and more about what happens in the immediate vicinity around a black hole, within the flattened disk of superheated material falling inexorably in toward the center. Using supercomputers, scientists can model the behavior of black holes’ accretion disks and see how gas behaves as it gets accelerated and drawn inward, heated to millions and even billions of degrees.
Here, an animation shows the activity around an active, non-rotating stellar-mass black hole. Taking 27 days to complete on a supercomputer at UT Austin, it shows “a turbulent froth orbiting the black hole” at relativistic speeds — that is, very close to the speed of light. Using this data, scientists are able to see how a black hole heats gas and emits different kids of x-rays… it’s the next best thing to being there! (Actually, it’s probably a much better thing than being there.)