Those discussions stimulated the young Hawking to pursue his own scientific vision. Sciama, on the other hand, was happy for Hawking to investigate the beginning of time.
If physicists wanted to understand the origin of the universe, Hawking had just shown them exactly where to look: a black hole. Black holes were a subject ripe for investigation in the early s. Although Karl Schwarzschild had found such objects lurking in the equations of general relativity back in , theoreticians viewed them as mere mathematical anomalies and were reluctant to believe they could actually exist.
Albeit frightening, their action is reasonably straightforward: black holes have such strong gravitational fields that nothing, not even light, can escape their grip. Any matter that falls into one is forever lost to the outside world. This, however, is a dagger in the heart of thermodynamics. The second law of thermodynamics is one of the most well-established laws of nature.
It states that the entropy, or level of disorder in a system, always increases. The second law gives form to the observation that ice cubes will melt into a puddle, but a puddle of water will never spontaneously turn into a block of ice. All matter contains entropy, so what happens when it is dropped into a black hole?
Is entropy lost along with it? If so, the total entropy of the universe goes down and black holes would violate the second law of thermodynamics. Hawking thought that this was fine. He was happy to discard any concept that stood in the way to a deeper truth. And if that meant the second law, then so be it. But Hawking met his match at a physics summer school in the French ski resort of Les Houches, France. Princeton University graduate student Jacob Bekenstein thought that the second law of thermodynamics should apply to black holes too.
A black hole hides its singularity with a boundary known as the event horizon. Nothing that crosses the event horizon can ever return to the outside. Bekenstein realised this was key to the entropy problem. Every time a black hole swallows matter, its entropy appears to be lost, and at the same time, its event horizon grows. So, Bekenstein suggested, what if — to preserve the second law — the area of the horizon is itself a measure of entropy? Hawking immediately disliked the idea and was angry that his own work had been used in support of a concept so flawed.
During a break from the lectures, Hawking got together with colleagues Brandon Carter, who also studied under Sciama, and James Bardeen, of the University of Washington, and confronted Bekenstein. The disagreement bothered Bekenstein. I was just out of my PhD. Back in Cambridge, Hawking set out to prove Bekenstein wrong. Rather than destroying the idea, he had confirmed it. Hawking now embraced the idea that thermodynamics played a part in black holes.
Anything that has entropy, he reasoned, also has a temperature — and anything that has a temperature can radiate. His original mistake, Hawking realised, was in only considering general relativity, which says that nothing — no particles, no heat — can escape the grip of a black hole. That changes when quantum mechanics comes into play.
According to quantum mechanics, fleeting pairs of particles and antiparticles are constantly appearing out of empty space, only to annihilate and disappear in the blink of an eye. When this happens in the vicinity of an event horizon, a particle-antiparticle pair can be separated — one falls behind the horizon while one escapes, leaving them forever unable to meet and annihilate.
Hawking's health remained a constant concern—a worry that was heightened in when he failed to appear at a conference in Arizona because of a chest infection. In April, Hawking, who had already announced he was retiring after 30 years from the post of Lucasian Professor of Mathematics at Cambridge, was rushed to the hospital for being what university officials described as "gravely ill," though he later made a full recovery.
Photo: Frederick M. In , Hawking's research turned him into a celebrity within the scientific world when he showed that black holes aren't the information vacuums that scientists had thought they were.
In simple terms, Hawking demonstrated that matter, in the form of radiation, can escape the gravitational force of a collapsed star. Another young cosmologist, Roger Penrose, had earlier discovered groundbreaking findings about the fate of stars and the creation of black holes, which tapped into Hawking's own fascination with how the universe began.
Hawking was named a fellow of the Royal Society at the age of 32, and later earned the prestigious Albert Einstein Award, among other honors. He also earned teaching stints at Caltech in Pasadena, California, where he served as visiting professor, and at Gonville and Caius College in Cambridge. In August , Hawking appeared at a conference in Sweden to discuss new theories about black holes and the vexing "information paradox.
In a March interview on Neil deGrasse Tyson 's Star Talk , Hawking addressed the topic of "what was around before the Big Bang" by stating there was nothing around. He said by applying a Euclidean approach to quantum gravity, which replaces real time with imaginary time, the history of the universe becomes like a four-dimensional curved surface, with no boundary. He suggested picturing this reality by thinking of imaginary time and real time as beginning at the Earth's South Pole, a point of space-time where the normal laws of physics hold; as there is nothing "south" of the South Pole, there was also nothing before the Big Bang.
In , at the age of 65, Hawking made an important step toward space travel. While visiting the Kennedy Space Center in Florida, he was given the opportunity to experience an environment without gravity. Over the course of two hours over the Atlantic, Hawking, a passenger on a modified Boeing , was freed from his wheelchair to experience bursts of weightlessness. Pictures of the freely floating physicist splashed across newspapers around the globe. I could have gone on and on.
Space, here I come! Hawking was scheduled to fly to the edge of space as one of Sir Richard Branson 's pioneer space tourists. He said in a statement, "Life on Earth is at the ever-increasing risk of being wiped out by a disaster, such as sudden global warming , nuclear war, a genetically engineered virus or other dangers.
I think the human race has no future if it doesn't go into space. I therefore want to encourage public interest in space. If there is such a thing as a rock-star scientist, Hawking embodied it. Other TV and movie appearances included:. In , Hawking showed off his humorous side on American television, making a guest appearance on The Big Bang Theory. Playing himself on this popular comedy about a group of young, geeky scientists, Hawking brings the theoretical physicist Sheldon Cooper Jim Parsons back to Earth after finding an error in his work.
Hawking earned kudos for this light-hearted effort. In November of , a film about the life of Hawking and Jane Wilde was released. The Theory of Everything stars Eddie Redmayne as Hawking and encompasses his early life and school days, his courtship and marriage to Wilde, the progression of his crippling disease and his scientific triumphs.
In May , Hawking hosted and narrated Genius , a six-part television series which enlists volunteers to tackle scientific questions that have been asked throughout history.
Being an optimist, I think they will. In , Hawkings had participated in a trial of a new headband-styled device called the iBrain.
The device is designed to "read" the wearer's thoughts by picking up "waves of electrical brain signals," which are then interpreted by a special algorithm, according to an article in The New York Times. This device could be a revolutionary aid to people with ALS. In , Hawking, among other top scientists, spoke out about the possible dangers of artificial intelligence, or AI, calling for more research to be done on all of possible ramifications of AI. Their comments were inspired by the Johnny Depp film Transcendence , which features a clash between humanity and technology.
Hawking reiterated this stance while speaking at a technology conference in Lisbon, Portugal, in November Noting how AI could potentially make gains in wiping out poverty and disease, but could also lead to such theoretically destructive actions as the development of autonomous weapons, he said, "We cannot know if we will be infinitely helped by AI, or ignored by it and sidelined, or conceivably destroyed by it. In July , Hawking held a news conference in London to announce the launch of a project called Breakthrough Listen.
Funded by Russian entrepreneur Yuri Milner, Breakthrough Listen was created to devote more resources to the discovery of extraterrestrial life. An overwhelming demand for access promptly crashed the university server, though the document still fielded a staggering 60, views before the end of its first day online. On March 14, , Hawking finally died of ALS, the disease that was supposed to have killed him more than 50 years earlier.
A family spokesman confirmed that the iconic scientist died at his home in Cambridge, England. The news touched many in his field and beyond.
Fellow theoretical physicist and author Lawrence Krauss tweeted: "A star just went out in the cosmos. We have lost an amazing human being. Hawking fought and tamed the cosmos bravely for 76 years and taught us all something important about what it truly means to celebrate about being human.
Hawking's children followed with a statement: "We are deeply saddened that our beloved father passed away today. He was a great scientist and an extraordinary man whose work and legacy will live on for many years. His courage and persistence with his brilliance and humor inspired people across the world. Later in the month, it was announced that Hawking's ashes would be interred at Westminster Abbey in London, alongside other scientific luminaries like Isaac Newton and Charles Darwin.
On May 2, , his final paper, titled "A smooth exit from eternal inflation? Submitted 10 days before his death, the new report, co-authored by Belgian physicist Thomas Hertog, disputes the idea that the universe will continue to expand. We strive for accuracy and fairness. If you see something that doesn't look right, contact us! Sir Tim Berners-Lee, inventor of the web, said: "We have lost a colossal mind and a wonderful spirit.
Rest in peace, Stephen Hawking," he said. The vice chancellor of the University of Cambridge - where Prof Hawking had studied and worked - Professor Stephen Toope, said he was a "unique individual" who would be remembered with "warmth and affection". Prof James Hartle, who worked with him to create the Hartle-Hawking wavefunction to explain the Big Bang, said Prof Hawking had a "unique" ability to "see through all the clutter in physics" and get to the point.
He told BBC Radio Four's Today programme: "My memory of him would be… first our work together as scientists and, second, as a human being whose whole story is a triumph over adversity [and] who inspired a lot of people, including me. 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 The comedian and presenter of the BBC's Stargazing Live Dara O'Briain said the scientist had an "immeasurable life" and "one of the few people I would call a hero of mine". Inside that shell, inside that body that was paralysed, was someone who was full of vigour, full of passion for life. British astronaut Tim Peake said Prof Hawking "inspired generations to look beyond our own blue planet and expand our understanding of the universe". Gian Giudice, head of theoretical physics at the European nuclear research laboratory CERN, said Prof Hawking had a "great impact" on the centre's research, adding: "A giant of our field has left us, but his immortal contributions will remain forever.
Apple's co-founder Steve Wozniak said: "Stephen Hawking's integrity and scientific dedication placed him above pure brilliance,". In his memoir he described how he felt when first diagnosed with motor neurone disease. But now, 50 years later, I can be quietly satisfied with my life. Speaking to the BBC in , his mother, Isobelle, described him as a "very normal young man".
She said: "He liked parties. He liked pretty girls - only pretty ones. He liked adventure and he did, to some extent, like work. Obituary: Stephen Hawking. Stephen Hawking in quotes. Scientist in the public eye. Five things you may not know.
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