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Dhaka Tribune

What Hawking showed us

Update : 16 Mar 2018, 12:47 AM
I was a poor PhD student at Cambridge when one day I came upon Stephen Hawking’s inaugural lecture Is the end in sight for theoretical physics? in a second-hand bookshop. Being a life-long bibliophile, I immediately recognized how rare this book was. It was the lecture that Stephen Hawking gave when he was inducted into the prestigious Lucasian Professorship (a chair which had been once held by Sir Isaac Newton and Paul Dirac, the eminent quantum physicist). It was the first edition, and until then it has never been reprinted. It is an old Cambridge tradition to “inaugurate” a professorship with a special lecture. Hawking’s lecture, which was delivered in 1980, was especially provocative because he was predicting that an eleven-dimensional theory known as supergravity was going to solve the fundamental problems of theoretical physics. It turned out that his optimism was premature, and years later when I was a student at Cambridge he gave part two of his famous lecture. My string theory lecturer, Malcolm Perry, who was one of Hawking’s first PhD students (and who would become my PhD supervisor) had to reschedule his class so he could attend the lecture, complaining loudly that he wished Stephen had gotten it right the first time around! Anyway, back to my story. The book was about 10 pounds or so, and way too expensive for my poor wallet. Yet I bought it and kept it carefully packed away with my stuff.
Stephen Hawking was the head of my research group at Cambridge, and academically my grandfather (his PhD student was my supervisor), and we got used to seeing him every day
Stephen Hawking was the head of my research group at Cambridge, and academically my grandfather (his PhD student was my supervisor), and we got used to seeing him every day. He would pay for the lunch for the gravitational physics group lunch seminars on Friday. Many of the students in the department attended because of the free pizzas and chicken wings, and he took us out to his favourite Thai restaurant once a year. Often at department parties, he would get bored of talking to the bigwigs and just come and hang out with the students. In 2002, right before I graduated and left Cambridge, I finally got up the courage to go and thank him during a party. He smiled and his then-wife and I made small talk. Eventually, I asked if he would autograph his Inaugural Lecture. He agreed, and in a day or two, I had his autograph on what would become my most prized and valuable possession. But his secretary had also inserted a smiling photo of him printed on copyright paper. I love that photo with his impish smile and a copy of Marilyn Monroe’s biography. Stephen really loved Marilyn Monroe. Perhaps Stephen’s greatest contribution to physics was his groundbreaking work on black holes. His early work on black holes established that black holes, like other large physical systems in the universe, satisfy the laws of thermodynamics. The traditional understanding of black holes was that they would, due to their enormous gravity, suck up everything but would not emit anything. A black hole is surrounded by an event horizon, which is an imaginary surface beyond which nothing could return. Eventually by using quantum theory on the vicinity of black holes, Stephen Hawking showed that black holes will emit radiation and that eventually because of this radiation, the black hole will evaporate and vanish. However, for realistic black holes in our universe, the time that it would take for a black hole to evaporate completely would be longer than the life-time of our universe. Even though it is unlikely that we would see a black hole evaporate any time soon, Hawking’s result caused an uproar in the physics world.Tibra Ali works on string theory and cosmology.
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