By Fr. (Dr.) Mathew Chandrankunnel –
Stephen Hawking, the legendary scientist has now become memory. Because of his shining brilliance, of his debilitating physical disability, of his controversial scientific and philosophical proposals and of his courageous confrontation with life made, Hawking a darling of humanity.
After his celebrated fist book A Brief History of Time, it was a fashion to keep the book in library exhibiting one’s own intellectual flavours in science. A life that challenged every moment of one’s own limitation, Hawking remained as a symbol of resilience and significance. His major scientific contribution was about the exploding black holes, where in which time is eternal or frozen and hence it would be relevant to examine his life and contributions as he now passed on to the sphere of beyond time and space!
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I read the Brief History of Time, in the year it was published 1988. My thesis guide Prof. Dr. Paul Dhooge, a specialist in the theory of relativity at the Department of Physics, University of Leuven, Belgium who worked with Roger Penrose, many a time asked me, ‘Why don’t you go and meet him?’. However, I wondered what I could talk to him, even if I meet him! His disabilities were so high and any meaningful communication would have been difficult and constraining.
However, he remained an enigma for me and every other human being; calculating in his brain, and churning out formulae, explaining the events in this universe. Hawking wrote the book Brief History of Time avoiding all mathematical formulae in a nontechnical style and for an audience who are interested in the cosmos, its beginning, expansion and its impending future. Theory of relativity and quantum mechanics were introduced as a back drop as these theories are the windows to the past and future of the universe and its evolutionary nature.
With mathematician Roger Penrose, Hawking did research on the black holes. The general assumption at that time was that black holes remain forever. Black holes are the end results of the evolution of stars. It was proposed by the Indian astronomer S. Chandrasekhar, nephew of C V Raman who was the first Asian to receive the Nobel Prize for physics. Though Chandrasekhar proposed black holes in 1930, the famous astronomer Arthur Eddington denied the proposal and it was rejected. However, astronomers searched for black holes in 1960s onwards and found them and Chandrasekhar also received Nobel prize.
A star-like sun remains by burning or fusing the hydrogen in its core to helium. A certain amount of matter is converted to energy in terms of the equation E = MC2 where E is energy and M amount of matter and C, the velocity of light. As the core has completely converted into helium, then the burning cross over to the periphery. There, the gravitational and the electromagnetic forces are having a tussle and since the gravity is weaker compared to the electro magnetic force since the mass is minimal. So the star expands and from far away it will be seen as a red giant and then explodes into a white dwarf. That is the last evolutionary stage of a star-like our sun. A star of the 10 size of our sun, in its evolution converts the hydrogen into helium and later the helium into carbon and ultimately into iron. Iron has a tendency to absorb energy and all the energy is absorbed and all on a sudden it explodes and even during day this explosion is visible. Such explosions are known as Supernova.
In 1052 AD there was such an explosion and it was detected by the Chinese astronomers and the remnants are known to be Crab Nebula. A 20-size star of sun, pass through the same evolutionary process and the whole of the matter is converted in to higher elements and it decreases its size. However, the mass is so heavy and intense and therefore the gravity is stronger and the electrons in the periphery are brought into the nucleus, collapsing the star into a Neutron star. This star will be of 10 KM radius and it curves the spacetime.
One spoon full of matter will be of trillions of KG. A star of 30 sizes of the sun will pass through the same process and ultimately since the gravity is intense, the whole matter will be converted into energy and will collapse into a 1 KM radius. The spacetime will be curved and it will look like a funnel and anything in its neighbourhood will be drawn into the accelerating disc and falling into the centre and nothing can escape even sunlight from such a collapsed star. Therefore, it is known as black hole. There is no way of detecting such black holes directly and hence the nick name black hole. So now they are found in every galaxy’s centre and just as sun holds the planets, the stars are held together by the black hole. Hawking proposed that black hole does not exist forever, but it evaporates and explodes into energy field.
To be continued tomorrow…
Prof. Dr. Mathew Chandrankunnel CMI is Director, Ecumenical Christian Centre, Whitefield, Bangalore. Fr. Chandrankunnel is a professor of philosophy of science at Dharmaram Vidya Kshetram and Christ University, both in Bangalore, India. He is the author of several books including “Philosophy of Quantum mechanics” and “Ascent to Truth: The Physics, philosophy and Religion of Galileo Galilei”. He is a scientist, philosopher and theologian.