The world has lost a great luminary of science. Brother Guy Consolmagno called Hawking a "scientist of admirable intuition, who knew even more extraordinarily to give a human face to cosmology and to astronomy."
Professor Hawking had a significant public following. I recall learning this lesson first-hand when he gave a public talk while I was a graduate student at the University of California at Berkeley.
There was so much interest that we had to book a venue to hold the hundreds of ticket-holders. I recall volunteering to serve as an usher. Later I would find out just how very much ushers were needed at this popular event. This is because dozens of disabled individuals found their way to this auditorium. I recall that Professor Hawking offered advice. He said not for everyone to see him as a role model and study mathematics, but rather for each person to find out what one does best and then do that one thing.
Hawking is probably most famous for writing his book on the history of the universe entitled, "A Brief History of Time," as well as for his work on black holes.
It is Hawking who discovered that the end state of a black hole is nothing. Just as a drop of water evaporates off the sidewalk on a hot day, leaving no trace of it behind, a black hole also evaporates away until one day it is, well, gone.
The idea is that near a black hole many particles are created and then destroyed over and over again nearly instantaneously. Relevantly, these short-lived "virtual" particles come and go only in pairs.
Let us imagine that such a virtual particle pair is created right on the edge or "event horizon" of a black hole. An instant later, when both members of the pair are meant to disappear according to the script, the script changes and one particle member escapes and stays real!
The result is a loss of energy from the black hole. In such a way a black hole can lose all its energy and disappear. Hawking accelerated our understanding of black holes and captured the imagination and dreams of the next generation of leaders in science and other fields. He will be greatly missed.