I thought it was really cool that Dr. Mathur got the opportunity to meet Dr. Stephen Hawking and worked with a college of Hawking! Fr. Mathur talked about how gravity affects a different kind of star and that a black hole is a collapsed star.
Hawking wrote a thesis on Hawking radiation in 1974. Hawking radiation is the electromagnetic radiation that is emitted by the black holes. Hawking also wrote a thesis in 1975 about a black hole information paradox; This is what made Hawking famous. Each star has different information in it and hawking questioned about what would happen when the star collapses. He said that the information in this said star is still there, but it eventually disappears in the black hole.
If we were able to back in time to look at the universe, we would see the universe as one point; only space but no time. The Hartle-Hawking wave function says that before the big bang, there was no time. Hawking and Hartle claim that the universe was a singularity before the big bang.
It was asked if the universe will keep expanding and Dr, Mathur explained that eventually, the universe will go through a “Big Crunch”, which will start a new big bang. Dr. Mathus also talked about how previous big bangs and big crunches might have happened but since the information from the stars disappears with black holes, we could never know if we’re in a cycle. I was surprised to find out that we know nothing about dark energy and dark matter!
I was also impressed and thought it was cool to hear about the personal encounters Dr. Mathur had with Steven Hawking. I was interested to hear all the questions that came out of this talk from the students too.