When he turned 70 in 2012, Stephen Hawking was honored with a special exhibit at London's Science Museum.
The tribute gave visitors an inside look at the life and work of one of the world's greatest minds.
“We have some of the first drafts of Hawking's key scientific papers," astronomy curator Alison Boyle says.
"And we wanted to do a survey of the key highlights of his career from the early 1960s and 1970s, right through now, and we also have examples of all the popular work he's done over the years.”
Born in Oxford, England, in 1942, Hawking studied at both Oxford and Cambridge Universities.
He became a math professor at Cambridge and held that post for more than 30 years.
In 2009, he left to head the Cambridge University Center for Theoretical Physics.
Hawking has spent his life working on big, bold ideas, according to David Devorkin, historian and curator at the Smithsonian's National Air and Space Museum in Washington.
“His primary passion is to understand physical reality," Devorkin says.
"What is time? What is space?
What is mass, and what do they have to do with one another other?
The big push at Cambridge is to reduce the universe to one equation that encompasses everything.”
Hawking's work has focused on bridging the gap between Albert Einstein's theory of relativity —which explains how the pull of gravity controls the motion of large objects like planets- and the theory of quantum physics, which deals with the behavior of particles on the subatomic scale.
Hawking found a wider audience for those ideas with the 1988 publication of his best-selling book, “A Brief History of Time.”
“The idea is that the universe is a logical one and one that follows certain rules," Devorkin says.
"It's out of that that he felt the necessity of a fundamental theory, because if the universe is knowable or logical, we should be able to figure out that logic, and that's what the fundamental theory is.”
Hawking is also celebrated for his seminal work on the strange cosmic phenomena known as black holes.
The London exhibit displayed the model Hawking once used to explain his ideas about the unimaginably dense, heavy objects whose powerful gravity swallows up everything that comes close, even light.
“It shows the gravitational pull of a black hole," says Science Museum curator Alison Boyle.
"So when a massive star collapses in on itself, it will keep and keep collapsing until it gets to a point of infinite density.
And that's called a singularity, and that's what's right inside a black hole.”
Stephen Hawking in his office at University of Cambridge, where he founded the Centre for Theoretical Cosmology.
Hawking applied the idea of singularity to the origin of the universe, which most scientists believe happened about 13 billion years ago in a cataclysmic explosion called the Big Bang.
“Much of our understanding of processes in the Big Bang come from Hawking's work linking black hole physics to Big Bang physics," Devorkin says, "and he did a better job at it than anyone else.”
Another of the physicist's noted contributions is a theory dubbed Hawking Radiation.
It proposes that black holes emit radiation and eventually evaporate and vanish.
It's an alternative explanation of the structure of the universe that also points to how it might end.
Since 1970, Hawking has been almost completely paralyzed by ALS, an incurable, neurodegenerative condition.
Confined to a wheelchair, he uses an advanced computer synthesizer to speak.
Despite his disabilities, he continues to work, write and travel.
At age 65, he was invited aboard a special zero-gravity jet to fulfill his dream of experiencing the weightlessness of a space-faring astronaut.
“It was amazing," Hawking said.
"The Zero-G part was wonderful, and the High-G part was no problem.
I could have gone on and on. Space, here I come!”
Speaking at a 2008 ceremony marking the 50th anniversary of the U.S. space agency, NASA, Hawking called for a new era in human space exploration, comparable, he said, to the European voyages to the New World more than 500 years ago.
“Spreading out into space will have an even greater effect," Hawking said.
"It will completely change the future of the human race and maybe determine whether we have any future at all.”
Hawking also posed some fundamental questions.
“What will we find when we go into space?" he asked.
"Is there alien life out there, or are we alone in the universe?”
Questions inspired by an indomitable mind, and Stephen Hawking's neverending quest to solve the mysteries of the universe.
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