Dr. Mathur’s beginning points about black holes seem so intimidating when compared to life on Earth; it gives perspective on how large the universe is, as well as how powerful some of the elements of the universe are. I like that he touched on each of the varying theories for black holes rather than just saying the theory we now know to be correct. Sharing each of the varying ideas helps visualize how scientists of the time were thinking about this new phenomenon and how they tried to conceptualize it.
One component of his talk that was unfamiliar to me was the concept of Hawking Radiation discovered in 1974. I had still been under the impression that once something passes the horizon of a black hole, it could never come out. It was surprising to learn this was not the case, and that black hole evaporation actually occurs over time. And while the process of this black hole evaporation is extremely slow, it would eventually disappear; based on Hawking’s reasoning. The particles evaporating from the black hole oftentimes are pulled back into the black hole because of the mass that is still left behind, and these particles are finally able to “escape” when they have generated enough energy; this is why this evaporation is such a slow process.
The well-known photo of a black hole can actually be misleading because the light that we observe in the photo is actually objects orbiting the black hole since we cannot see anything past the horizon. Some of the light we see is also the way light is bending over the black hole from the back as it rotates. The light becomes so bent that we can’t actually see what was there before.
Overall, I thought this was one of the most interesting talks in the course thus far. As much as I do enjoy history combined with biology, these types of lectures give the audience a new perspective on the sheer size of the universe surrounding our planet and how it could affect us at some point.