I was a lucky witness to making of history in 1987. From December 14 to December 19, 1987 at International Conference on Gravitation and Cosmology (ICGC-1987), held at Hotel Mandovi, Panaji many collaborators of Stephen Hawking were present. Most of the focus was on gravitational cosmology, quantum gravity and thermodynamics of black holes. Due to his disability Hawking couldn’t attend ICGC but his absence was more than filled by participation of his PhD guide Dennis Sciama, Roger Penrose, Jim Hartle and Abhay Ashtekar while on sidelines Sir Fred Hoyle and main organizer and host astrophysicist Jayant Naralikar enjoyed the proceedings as they might have recalled the day in June 1964 when, then a young PhD student, Stephen Hawking had caused them some public embarrassment.
Hawking had the habit of putting baits and dismissing some rival theories before accepting. He had failed miserably in challenging possibility of detecting Higgs Boson. Young Princeton University graduate student Jacob Berkenstein was one of his targets. While trying to prove young Berkenstein wrong, Hawking stumbled on what has come to be known as ‘Hawking Radiation’. Hawking showed that black holes emit radiation. The equation of black hole entropy is known as the Berkenstein-Hawking entropy equation. Entropy of black hole is equal to pi, multiplied by Boltzmann’s constant and cube of speed of light and this is divided by two times the product of Planck’s constant multiplied by Newton’s gravitational constant. Hawking loved this equation because it was closer to “theory of everything”- Newton, Boltzmann, Planck, Einstein all contained in a single beautiful equation.
Hawking arrived at Cambridge University in 1962 hoping to do his PhD under Fred Hoyle, the supervisor he selected. But he found that Hoyle already had the enough students with him. So reluctantly he had to join Denis Sciama. We don’t know whether he held a grudge against Hoyle. It was bad year for him because he was diagnosed with a degenerative motor neuron disease. Then he had a famous intellectual argument with Fred Hoyle, vividly captured by his biographers – Michael White and John Gribbin (1992). They inform us that “’Fred Hoyle was a very big name in the physics department of Cambridge University, widely known for his ideas about the origins of the Universe.
Hoyle was very much involved with the steady state theory of the Universe developed by the mathematician Hermann Bondi at King’s College, London, and the astronomer Thomas Gold. “Now these biographers introduce well known Indian astrophysicist Jayant Naralikar in the scene.” As well as developing his theory of the origin of the Universe, Hoyle acted as supervisor to a select group of students. One of his charges was a graduate student named Jayant Narlikar. Narlikar had been assigned the task of working through some of the mathematics for Hoyle’s theory as part of the research material for his Ph.D. He also happened to occupy the office next to Hawking’s. Then comes most suspenseful part in the story. “Hawking became very interested in Narlikar’s equations. Without too much persuasion, Narlikar shared the research material he was working on and Hawking began to develop the theories further. During the next few months Hawking spent more and more time walking between his friend’s office and his own, clutching pages full of mathematical interpretations in one hand and leaning heavily on his newly acquired walking stick with the other.”
Hawking’s biographers defend him by commenting that: “Hawking had no malicious intent toward Hoyle or, indeed, Narlikar. He was quite simply curious about the material and was floundering with his own projects…. Before too long things came to a head.” Then we witness what happened in June 1964 as narrated by these biographers: “Hoyle decided to make a public announcement of his findings at a meeting of the Royal Society in London. Hoyle gave his talk to around a hundred people; at the end there was warm applause and the usual post-lecture hubbub of conversation. Then he asked if there were any questions. Naturally Hawking had attended and had followed the arguments closely. He stood up slowly, clutching his stick. The room fell silent. ‘The quantity you’re talking about diverges,’ he said. Subdued murmurs passed around the audience. The gathered scientists saw immediately that, if Hawking’s assertion were correct, Hoyle’s latest offering would be shown to be false. ‘Of course it doesn’t diverge,’ Hoyle replied. ‘It does,’ came Hawking’s defiant reply. Hoyle paused and surveyed the room for a moment. The audience was silent. ‘How do you know?’ he snapped. ‘Because I worked it out,’ Hawking said slowly. An embarrassed laugh passed through the room. This was the last thing Hoyle wanted to hear. He was furious with the young upstart. But any enmity between the two men was short lived—Hawking had demonstrated himself to be too good a physicist for that. But Hoyle considered Hawking’s action to be unethical and told him so. In return, Hawking and others pointed out that Hoyle had been unethical in announcing results that had not been verified. The only innocent party, who no doubt had to bear the full brunt of Hoyle’s anger, was the middleman, Narlikar.”
After Hawking’s death however, astrophysicist Jayant Naralikar paid him handsome tributes. Hopefully as wished by Hawking, Berkenstein-Hawking entropy equation would be inscribed on his tombstone.