Stephen Hawking Dead; updates: Physicist had warned that humans would have to leave Earth in 100 years

Prof Pankaj Joshi professor of astronomy and astrophysics at the Tata Institute of Fundamental Research reacts to Stephen Hawking's death

I have met many scientists, but Hawking was the sharpest mind I ever met. In my seminar at Cambridge, as soon as I stated speaking on my theorem, he made
a sudden, penetrating query: "How do I believe this?". I explained the logic and he said, "Ah, that is the point."

Hawking's greatest contribution was on Cosmology and black hole physics. Together with Roger Penrose and Robert Geroch, he gave detailed theorems in the late 1960s and early 1970s, to show that Space-time Singularities must occur when massive stars in the Universe collapse at the end of their life cycles, and in Cosmology, at the beginning of the Universe. Such singularities are so to say the boundaries of the Universe, where all physical quantities such as densities, temperatures and others blow up and diverge.

Further, Roger Penrose proposed in 1969, that such  singularities of star collapse must be hidden within black holes or the event horizons of gravity, and this gave rise to the massive science of black holes, and their astrophysical applications, as we know it.

We have had a great scientific engagement over past many years and decades. Hawking was a strong believer that the singularities of star collapse must be hidden necessarily within black holes. The work from our own group in India, and many other groups internationally showed that we can also have Naked Singularities, not hidden within black holes. Finally, a few years ago, Hawking accepted that in fact.

He was an extraordinary human being. I spent several months with him in Cambridge, in 1983, and then met him many times after.

Hawking the gambler

Stephen Hawking was a terrible gambler while making scientific predictions. In 1975, he bet with Kip Thorne that black holes did not exist and the wager was one year's subscription of the adult `Penthouse` magazine. There is no prize in guessing who won that bet as Kip Thorne won the 2017 Nobel prize in Physics
for his contributions to the discovery of gravitational waves.

Two decades ago, Hawking again argued that black holes swallow all information forever and made a wager with Thorne and Preskill. He conceded the bet in a conference in Dublin in July 2004.

Hawking made another bet in 2000 and argued that the Gold particle (Higgs Boson) would never be found. The LHC collaboration discovered the Higgs Boson in 2012.

In 2014, Hawking claimed victory on a wager about Cosmic inflation with Professor Turok after hearing about  the discovery of primordial gravitational waves, 
announced by the Harvard-Smithsonian Centre for Astrophysics. Unfortunately, this discovery turned out  to incorrect due to various technical complications.

We hope that his recent bet of 2010 also remains wrong. In this bet he stated that Aliens, when we eventually discover them, would likely be hostile.

-TIFR professor A Gopakumar

Gautam Mandal, professor of theoretical physics, TIFR remembers Hawking's time in India

Gautam Mandal, professor of theoretical physics, Tata Institute of Fundamental Research, Mumbai said,"Multiple generations will mourn the passing away of Stephen Hawking today, which in itself says a lot. Hawking’s life as a person in general and his work in particular have been hugely inspirational to a lot of people around the world. I, and my colleagues in the physics community, have been inspired by his work since 1974, when he pointed out a possible conflict between the two pillars of modern science — quantum mechanics and the theory of relativity. He showed the inconsistency in the two theories mathematically, which later came to be known as the Hawking’s Paradox. This has been a challenge for scientists since 1974, and we still do not have a resolution for it."

"Every once in a while, it seems like somebody has found a solution, but it always turns out to be a false alarm. He was a man who encouraged actively any effort to resolve it, but now after his demise, there will be no one to say with authority if it actually has been resolved, in case someone make a claim. Personally, I have spoken to Dr Hawking at dinners and various other occasions through the years. I found that he was a man of amazing vitality and he had a strong British sense of humour. The fact that he continued with his academic work though his advancing years and even after his health deteriorated, says a lot," he added.

Speaking of the time Hawking was in India, he said, "There is international conference on string theory that happens every year around the world, and in 2001, it was held in India. Hawking, who was already a world renowned celebrity, visited TIFR then, and because of him, the conference got a lot more coverage than I normally would in the Indian press. I was part of the programme committee, so I got to witness his jovial, non-serious side first-hand. By the time he arrived, everyone was already waiting for him. I did meet him after that too, but his health had taken a serious toll on him. But he still kept writing amazing papers."

Stephen Hawking's publications

Stephen Hawking was a prolific author with a knack for making books on challenging scientific topics engaging to a wide spectrum of readers. The physicist is best known for his best-selling 1988 classic "A Brief History of Time: From the Big Bang to Black Holes," which was intended to help people without a strong scientific background understand key questions of physics and human existence.

Among his other books are:

— "George and the Unbreakable Code" and other stories: Written by Hawking and his daughter, Lucy, this was a series of illustrated children's books to explain "secret keys to the universe" to younger readers. The books deal with complex topics including the Big Bang.

— "My Brief History": A very personal memoir published in 2013 in which Hawking deals among other things with his childhood, his evolution as a thinker and scientist, the impact of his ALS diagnosis when he was 21 and the ways in which the prospect of an early death affected his work.

— "The Grand Design": Hawking said this 2010 book co-written with American physicist Leonard Mlodinow was intended to address important unanswered questions such as why there is a universe and whether the universe needed a creator and designer. Hawking said his thinking had been influenced by significant advancements in physics that had followed publication of "A Brief History of Time."

AP

Quotations from Stephen Hawking

Stephen Hawking possessed an uncanny ability to come up with memorable phrases and sayings that summed up his world view:

— "We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the universe. That makes us something very special."

— "Life would be tragic if it weren't funny."

— "My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all."

— "I believe the simplest explanation is, there is no God. No one created the universe and no one directs our fate. This leads me to a profound realization that there probably is no heaven and no afterlife either. We have this one life to appreciate the grand design of the universe and for that, I am extremely grateful."

— "If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans."

AP

'His passing has left an intellectual vacuum,' tweeted noted astrophysicist Neil deGrasse Tyson

His passing has left an intellectual vacuum in his wake. But it's not empty. Think of it as a kind of vacuum energy permeating the fabric of spacetime that defies measure. Stephen Hawking, RIP 1942-2018. pic.twitter.com/nAanMySqkt

— Neil deGrasse Tyson (@neiltyson) March 14, 2018

Former ISRO chairman Krishnaswamy Kasturirangan on Stephen Hawking

"This is a great loss to the scientific community. I have met Dr Hawking a couple of times; I remember very fondly attending some of his absolutely brilliant lectures on the evolution of the universe and its structure. Personally, I had the great privilege of meeting Dr Hawking on a visit to the Sistine Chapel in Vatican City along with Dr CNR Rao. Dr Rao, Dr Hawking and I were clubbed in one group on that tour, and we took several rounds of the beautiful structures in the historical city," said former ISRO chairman Krishnaswamy Kasturirangan.

"Hawking spent a lot of time going through the details of Michelangelo’s work and all other paintings that we could see. Hawking was just lost in the amazing work done by Michelangelo — you could see it in his face even though he is usually not expressive. He sometimes looks a little asleep but that day, you could tell he was so engrossed in everything around him! The fact that the city is the epicentre of Christianity in the world mattered little — Hawking has a lot of faith in human values and that’s all that matters," he added.

Stephen Hawking’s pioneering work made our world a better place, says Narendra Modi

Professor Stephen Hawking was an outstanding scientist and academic. His grit and tenacity inspired people all over the world. His demise is anguishing. Professor Hawking’s pioneering work made our world a better place. May his soul rest in peace.

— Narendra Modi (@narendramodi) March 14, 2018

NASA remembers Stephen Hawking

Remembering Stephen Hawking, a renowned physicist and ambassador of science. His theories unlocked a universe of possibilities that we & the world are exploring. May you keep flying like superman in microgravity, as you said to astronauts on @Space_Station in 2014 pic.twitter.com/FeR4fd2zZ5

— NASA (@NASA) March 14, 2018

Humans must leave Earth in 100 years, colonise another planet to survive: Stephen Hawking

Humans will need to colonise another planet within the next 100 years to survive climate change, asteroid strikes and overpopulation, Stephen Hawking had said.

In a documentary, Expedition New Earth — part of the BBC's new science season Tomorrow's World — Hawking and his former student Christophe Galfard travelled the world to find out how humans could survive in outer space.

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