Make a list of the world's most popular scientists, and Stephen Hawking's name will be near or at the very top of the list.
Hawking, the author of A Brief History of Time and a professor at the University of Cambridge, is known as much for his contributions to theoretical cosmology and quantum gravity as for his willingness to make science accessible for the general public, says science writer Kitty Ferguson.
"It's not dumbing down [science]; it's really making it accessible, hopefully, to a lot of people," she tells Fresh Air's Terry Gross.
Ferguson, who helped Hawking edit his 2001 book The Universe in a Nutshell, is the author of a new Hawking biography, Stephen Hawking: An Unfettered Mind. Written with Hawking's blessing, the book traces his life from childhood to Oxford, and then to his graduate work at Cambridge in the early 1960s, where he was diagnosed with a motor neuron disease and given less than two years to live.
But Hawking's disease has progressed slowly, while his personal and professional life has flourished. He celebrates his 70th birthday this January, says Ferguson, and continues to work on projects despite having very limited use of his physical body. (He communicates using a voice synthesizer, which he controls using a muscle in his cheek.)
"It's just so interesting to see how he came to terms with [his illness]," says Ferguson. "What he says is that it wasn't courage. [He says] 'I just did what I had to do.' ... He took to listening to a lot of Richard Wagner, thinking of himself as a rather tragic hero. His mind went through all kinds of ways of dealing with that type of problem, but eventually, I think, he realized that theoretical physics was kind of a great escape from it."
Hawking Radiation And A Unified Theory Of Everything
In the 1970s, Hawking discovered what is now called "Hawking radiation." At the time, his discovery was controversial because many scientists — including Hawking — had believed that nothing could ever come out of a black hole, so a black hole could never get any smaller.
But Hawking postulated that if two individual particles were right at the edge of a black hole, and one of them happened to fall into the black hole, then the other particle could escape out into space, and appear as radiation being emitted from the black hole. Therefore, black holes could lose both mass and energy — and could, in fact, grow smaller.
Hawking's discovery raised many questions about what goes on inside black holes and our universe itself, says Ferguson.
"[His discovery raised questions like] 'What happens to the star that collapsed that formed the black hole? What happens to all of that when the black hole disappears entirely?' " she says. "And does this mean that this information is completely lost to our universe? And if it is ... to physics, that's a huge problem. Because if information can be lost from the universe, that's a violation of a law that says it can't disappear."
Hawking has also pursued what is called "theory of everything," which is conceptually an idea that there should be one theory from which everything else in the universe can be explained or derived.
"He has been predicting for most of his career that we will find it," says Ferguson. "Recently he has decided that it's probably going to be impossible for anybody, ever, to find the theory of everything. And this is a huge turnaround. He thinks we'll come up with some theories that are approximations ... but we'll never be able to know the underlying mysterious theory that would really explain the entire universe."
On time travel
"Someone recently asked him, 'If time travel were possible, what would you go back to in your life?' And you would expect him to say his discovery of Hawking radiation or a big prize [he'd won]. What he said was he would go back to the birth of his first child, his son Robert."
On how Hawking communicates
"When he sees the part of the screen that has the word that he's looking for, he punches a little mouse. Then the screen changes and we see lines of words scrolling down, and those are the words from that part of the screen. Then when he sees the word he wants, he activates his little switch again. Then you see the screen changing again and you see the words, and when he sees the next word he wants, he punches the device again. Then that word goes across the bottom of the screen. And he builds his sentence at the bottom of a screen. When he gets the sentence completed, he makes another movement, which indicates that his synthetic voice should speak that sentence. ... It sounds simple, but it's not simple. It moves at the speed of a video game, and very often he misses a word or misses the line, and then the whole thing has to start over. What that means is that working with him can be frustrating. Very often, you know what word he's after. You know what word he wants to capture. But protocol says you do not second-guess him. You do not move ahead and say, 'Stephen, I know what you're trying to say.' You let him finish. Because he's going to finish anyway. It would be impolite, as it would be to interrupt anybody talking."
On Hawking's singularity theory and no-boundary proposal
"He likes to describe that as though you were traveling backward on a globe of the Earth. When you get to the South Pole, the concept of 'south' no longer means anything. You don't say an airplane flew south of the South Pole. So it's the same thing — time becomes meaningless. Now when you start to think about that, first of all, Hawking says that relieves us of need for creator. There doesn't have to be a creation. It just started. And it was all kind of space dimensions, no time dimensions. What I find really interesting about that is that it's not a new idea. It's an idea you find in early Christian and Jewish philosophers like Philo of Alexandria or Augustine. They both conceived of a universe in which time didn't exist outside of our creation. Time was part of the creator. And God exists outside of time in the eternal now. It's the same idea. It was not new to theology, not new to philosophy, but very new to physics."
On Hawking's popularity
"He is popular because he deals with things right on the border of human knowledge. The origin of the universe, black holes — these are questions that are out on the edge, on the frontier between the known and unknown and the possibly unknowable. I love the phrase of what Wheeler, the American physicist, called the flaming ramparts of the world. [Hawking] tries to take us with him on this adventure, and it is fun and it's mind-blowing and wonderful."
On the Large Hadron Collider and the Higgs boson particle
"He has placed a bet that the Higgs particle will not be found. ... One of the mysteries in physics is what gives elementary particles — electrons, quarks — their mass. Mass, we often define as how many matter particles there are in an object. That becomes a little stupid when we're talking about a thing that is just one matter particle itself. So there's another definition for mass, which is: the resistance you feel if you push against something ... and where does that resistance come from? That's the mystery that the Higgs particle would solve. ... That's what we're looking for, this Higgs field. The Large Hadron Collider, what it does is accelerate particles to nearly the speed of light and then slams them together in these head-on collisons, and hopefully in the debris of one of those collisions — just in a split second — a minuscule part of the Higgs field will break away and that will be the Higgs particle. ... So far, they have pretty good evidence that they may have seen it, but it's not definitive yet."