I found out just before going to bed in the early morning today that Stephen Hawking, one of the great theoretical physicists of the 20th century, passed away today at the age of 76. Hawking had been diagnosed with ALS (amyotrophic lateral sclerosis, also called Lou Gehrig’s disease) when he was 21 and was told that he would probably have only two more years to live. During the 55 years between his date of diagnosis and his actual death today, he (together with others) proved the inevitability of singularities in classical general relativity, united quantum theory and GR to predict the existence of radiation from black holes, helping to establish the theory of black hole thermodynamics. He developed path integral methods for dealing with quantum gravity, proposed fascinating and fruitful ideas in the area of cosmology. In short, his was a remarkably productive life, purely from the perspective of theoretical physics.

Of course, Hawking also became the most iconic physicist of the late 20th century. Bound to a wheelchair, and forced to speak first through an interpreter, then through a synthesizer, he became a pop-cultural phenomenon. His book (and Errol Morris’ documentary of the same name), A Brief History of Time was an inspiration to me when I read it at age 13, and the subsequent eight re-readings over the next several years. I was able to measure my own growth as a physicist through the additional fractions of his book that I was finally able to understand.

Hawking’s writings and life story sparked my dream of becoming a theoretical physicist, and my goal of studying at Cambridge. Amazingly, both of these things somehow happened. While there, I had the great good fortune of meeting Hawking one-on-one for an hour. We exchanged a precious few ideas, and I gained a memory I will treasure for a lifetime.

Stephen Hawking never directly mentored me, but he nevertheless was as significant a role model and inspiration as anybody in my life. Thank you Stephen. I will miss you.

Roger Penrose, one of Hawking’s close collaborators and intellectual sparring partners has written an obituary here.

John Preskill, a theoretical physicist at Caltech, and winner of bets against Stephen Hawking has written a lovely poem to honor him.

John Baez, a mathematical physicist, has some reflections on Hawking here.

Nathan Myhrvold, a former postdoc of Hawking’s (he left physics to pursue other interests), describes working with him here.