If Black Holes are Black, Then How Do We See Them?

Professor Michael Nowak, Department of Physics, Washington University
November 3, 2018 at 10:00 am
52 McMillan
Event Description 

Astrophysical black holes are in some ways the simplest objects in Nature, being described by only two quantities: mass and spin. A major goal of astrophysical research into these objects has been to measure their mass and spin, and then further determine if we see the associated "exotic" effects of the warping of space time predicted by Einstein's General Theory Relativity. However, because black holes are in fact (for all practical purposes) black voids, we cannot test these theories with direct observations of them, but instead we look to see how they affect their surroundings. In this talk I will describe recent radio, infrared, and very importantly X-ray observations of material surrounding black holes point towards the verifiable existence of these exotic objects. Furthermore I will describe evidence that we are in fact observing the effects of a black holes extreme gravity on their surrounding environment and are seeing manifestations of General Relativity. Finally, I will discuss the efforts currently being made by the Event Horizon Telescope, which may in the not too distant future, provide us with our first image of a black hole.