Stephen Hawking passes away at 76: Indian scientists remember the man who defied odds to unlock secrets of space and time

Celebrated physicist Stephen Hawking, whose mental genius and physical disability made him a household name and inspiration across generations, died on Wednesday. He was 76.

Hawking’s formidable mind probed the very limits of human understanding both in the vastness of space and in the bizarre sub-molecular world of quantum theory, which he said could predict what happens at the beginning and end of time.

Tributes began pouring in from scientists around the world, lauding him as an inspiration. American astrophysicist Neil deGrasse Tyson tweeted his condolences: "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," joining thousands of others on social media.

Here is how scientists here in India reacted to the sad demise of the legendary scientist:

Gautam Mandal, theoretical physicist

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, has 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 makes a claim.

Personally, I have spoken to Hawking at dinners and various other occasions through the years. I found that he was a man of amazing vitality and 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.

There is an 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 it 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 at the venue, everyone was already waiting for him.

Krishnaswamy Kasturirangan, former ISRO chairman

This is a great loss to the scientific community. I have met 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. Rao, Hawking and I were clubbed in one group on that tour, and we took several rounds of the beautiful structures in the historical city.

Hawking spent a lot of time going through the details of Michelangelo’s work and all other paintings that we could see. He 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.

Professionally, he was a cosmologist par excellence, working in the fundamentals of the universe etc. In that particularly, he studied and mastered theories on the thermodynamics of black holes. Everyone understands black holes as something that continuously absorbs matter and radiation from outside but never lets it out. But Hawking had a contradictory view about the properties of black holes which completely changed our knowledge of the subject.

He answered the question on why we should explore other planetary systems for future habitats of human beings quite well. He had a point that we cannot afford to have humanity exposed to a single-point failure, where an asteroid comes and strikes the planet and wipes out human population, or by an outbreak of a deadly disease, or a nuclear holocaust. He said we should have alternatives for humans to inhabit other planets in these eventualities. He was a great champion of many such ideas with an eye at the future of humankind, ideas that have inspired even institutions like ISRO.

A Gopakumar, gravitational-wave astrophysicist

I am just a small fish in the ocean of physicists around the world but this news comes as a shock to the entire scientific community. The work he did in both classical and quantum areas of physics is unparalleled, and his connect with the layperson was also phenomenal. This legacy will live on, long after this piece of news fades away.

I'll share some stories that are quite famous in the scientific community:

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 magazine Penthouse. 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 God 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 from 2010 also remains wrong, where he stated that aliens, when we eventually discover them, would likely be hostile.

Pankaj Joshi, professor of astronomy and astrophysics at TIFR, Mumbai

I have met many scientists, but Hawking was the sharpest mind I ever met. In my seminar at Cambridge, as soon as I started speaking on my theorem, he made a sudden, penetrating query: "How do I believe this?" When I explained the logic, 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. Such singularities are like the boundaries of the Universe, where all physical quantities such as densities, temperatures etc 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 entire science of black holes, and their astrophysical applications as we now know it.

Hawking and I have had 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 fact.

He was an extraordinary human being. I spent several months with him in Cambridge, in 1983, and then had the privilege of meeting him many times after.

G Madhavan Nair, former ISRO chairman

Hawking was one person who saw beyond the existing scientific approach and phenomena. He thought differently and tried to find something different. But beyond his academic prowess, he was a popular scientist: he understood the scientific principles very well and translated them for the layperson.

Using work done by Newton, Einstein and others, Hawking explored the universe like never before and left questions for us, like what was there before the beginning of the universe. This is a good pointer for young scientists.

The other thing is, how the human brain, even after severe physical ailments in the body, can work with sheer willpower, and how one can use their brain in such a creative and highly imaginative way. The innovations will come only through the kind of creativity Hawkins had demonstrated.

Our technologies at ISRO continuously strive to explain the phenomena Hawking has demonstrated theoretically. Our Astrosat is already a step in that direction.

Kunal Kisley, co-founder and CEO of Integration Wizards, Enterprise mobility

It was a rather unusual evening in an otherwise packed day at IIT Bombay. Some of the labs in the second half were cancelled, the lunch was bearable and the weather was alright. Stephen Hawking was in India addressing a series of lectures. Like almost everyone one in my college and generation I had read 'Brief History of Time' a few years ago and was quite impressed with his ability to explain what can arguably be the most complex subject - Time. We were aware that he was going to address the people of Mumbai. Quite naturally the passes were sold out. With some newly acquired skills from IIT's 'jugaad' system, I was able to procure two passes for me and my roommate.

Tata Institute of Fundamental Research has a rather imposing auditorium (or at least had it almost two decades ago) named after Dr Homi Bhabha. It was an uneasy wait of over 15 minutes after we were all seated and ready for the lecture. Dr Hawking’s scientific achievements were well known but his physical condition was no less known. While he had literally been exploring the universe, the fact that he was doing it without even moving (or being able to move) was mind-boggling.

It is human tendency to create a mental picture of an anxiously awaited event. My image of the man was rather sombre. I expected him to bear marks of a continuous battle with his incapacity. If perseverance had a form I expected it to look like Hawking.

The actual lecture, however, started with a cartoon show followed by Hawking's rather mechanised (not mechanical) laughter. The Cartoon show was average, his jokes also did not really compare to his otherwise high standards of ideas but his humour was free. You can capture a man in his own body but enslaving him is quite another story.

For the next hour or so he took us deep into space showing how string theory might actually reconcile the apparent conflict with physics at the particle level (Quantum Physics) and the one that talks about billion light years long stretches of spacetime continuum (Relativity).

Hawking has since then continued to reshape/influence our ideas about the universe through his pathbreaking research in cosmology. A lot of all we know about black holes is from his research. His take on the dangers of artificial intelligence is quite commonly understood and repeated. As he puts it, "the emergence of artificial intelligence could be the worst event in the history of our civilization" and urged creators of AI to "employ best practice and effective management."

That evening had a lasting impact on me. It led me to believe the answers we seek are within. If a man can understand an object like a black hole, which by definition should be impossible to understand (information cannot escape a black hole), he must already have known it. Knowing is probably a process of remembering all that we already know.

He was a wizard among us. Is there an alternate version of him somewhere? Is there another reality beyond the event horizon? We will never know. At least, not yet!