John Moffat does not look particularly threatening. With his white hair and vaguely European accent, the mild-mannered physicist can walk unnoticed along the streets of Waterloo, Ont., where he has worked for the past three years.
However, when it comes to explaining the structure of the universe, Dr. Moffat -- or at least his ideas -- are closer to the edge. For every seemingly established idea in physics, from Albert Einstein's theory of gravity, to string theory, to cosmic inflation, he has an alternative approach. His non-conformity has won him both friends and enemies over the years in a career that has spanned more than half a century (he recently celebrated his 70th birthday).
"John is a bit of an iconoclast," says Clifford Will, a leading gravity expert at Washington University in St. Louis. "His approach has always been a bit perpendicular to what everyone else is doing."
Physics was not Dr. Moffat's first career choice. Born in Denmark, he turned to painting at an early age. He dropped out of school to pursue the artist's life in Paris, where his abstract paintings were displayed alongside those of Russian master Serge Polyakoff. (Dr. Moffat still paints; he had a display at the Lindsay Gallery in Lindsay, Ont., northwest of Toronto, last spring.)
However, when he ran short of funds, Dr. Moffat returned to Copenhagen, where he soon discovered a second skill. Poring over physics books in the public library, he found that he had a knack for relativity and quantum theory, right down to their thorny mathematical innards. He started writing scientific papers, and sent a couple of them to Albert Einstein, who, to his surprise, seemed genuinely interested in his work. The two men corresponded for several years, until Einstein's death in 1955.
Over the next few years, Dr. Moffat rubbed shoulders with Europe's top physicists, including Niels Bohr and Erwin Schrodinger, of quantum-theory fame, and Abdus Salam, who would later win a Nobel Prize for his work in particle physics. With the help of Dennis Sciama, a physicist who also mentored Stephen Hawking, Dr. Moffat entered Trinity College at Cambridge. He became the first student in the college's history to be admitted to a PhD program without an undergraduate degree.
By this time, Dr. Moffat was already establishing himself as a maverick. In his first two years at Cambridge, he wrote papers on differential geometry and on modifications to Einstein's theory of gravity, known as general relativity.
He also worked on "unified field theories." Considered unpopular at the time, this was the attempt to merge general relativity with electromagnetism; it was this quest that had obsessed (and ultimately frustrated) Einstein in the final decades of his life.
Dr. Moffat later turned to particle physics and quantum field theory, an outgrowth of quantum mechanics that attempts to describe the universe in terms of particles and fields.
After a few years in the United States, Dr. Moffat was offered a job at the University of Toronto in 1963, and became a tenured professor one year later. It would be his home for the next three decades.
At U of T, his unorthodox approach to physics continued. In the 1970s and 1980s, he further explored modifications to general relativity, including a "non-symmetric gravitational theory," in which extra terms are added to Einstein's equations (think of it as giving space a "twist" in addition to being curved).
But it was in the early 1990s that he came up with the idea that would eventually make him -- sort of -- famous.
According to special relativity, the first part of Einstein's revolutionary theory, nothing can travel faster than light. But suppose that the speed of light has varied over time, Dr. Moffat suggested.
If light had travelled faster billions of years ago, he argued, it might help to explain some of the strange properties the universe has today. For example, astronomers wonder why distant parts of the universe seem so much alike: No matter where they aim their telescopes, they see the same kinds of galaxies distributed with roughly the same density across the sky.
Dr. Moffat's paper on the subject, published in the International Journal of Modern Physics, was more or less ignored. Then, in 1998, a Portuguese-born physicist named Joao Magueijo, based at Imperial College in London, came up with the same idea. Dr. Magueijo, with collaborator Andrew Albrecht of the University of California at Davis, published his own speed-of-light paper in Physical Review, a journal that had earlier rejected Dr. Moffat's paper on the same subject.
This time, people did take notice. The Sunday Times of London wrote about Dr. Magueijo's work; Britain's Channel 4 made him the focus of a documentary; the glossy magazine SEED splashed his photo across its pages. None mentioned Dr. Moffat.
Even the Canadian media gave Dr. Moffat short shrift, rarely mentioning his contribution. Perhaps the fact that Dr. Magueijo is half Dr. Moffat's age, and could pass for a rock star, is a factor.
"He's a younger physicist, and very photogenic; I'm an older physicist and not as photogenic," Dr. Moffat concedes, laughing softly. He says he doesn't dwell on the matter, but adds: "You don't have that many significant ideas in your life as a physicist --they're like your children; you don't want them taken away from you."
Dr. Moffat doesn't blame Dr. Magueijo for any of the speed-of-light fallout. He found out about his paper before it was published, just in time to get Physical Review to add a footnote acknowledging Dr. Moffat's priority. And Dr. Magueijo's book, Faster than the Speed of Light, devotes a dozen pages or so to Dr. Moffat and his work, and praises him as a pioneer in the field (albeit more than 200 pages into the book). The two men have become friends.
Meanwhile, the notion of a variable speed of light ("VSL" to insiders) -- and, in general, the notion of physical "constants" that can vary over time -- has taken off. Not quite mainstream, perhaps, but the idea is certainly more plausible than it was just a few years ago.
Some of the evidence comes from observations of the "fine-structure constant," a measure of the strength of the electromagnetic force that is linked not only to the charge of an electron but also to the speed of light and to Planck's constant, the fundamental constant of quantum theory. There are hints that the fine-structure constant may have changed very slightly over the eons, in turn suggesting that one of the parameters it is linked to -- perhaps the speed of light -- has also changed.
Dr. Moffat's original paper has now been cited more than 100 times in the scientific literature.
The VSL affair may have been the most dramatic episode in recent Moffat history, but, from a broader perspective, it's not that unusual in the rarefied world of theoretical physics. After all, this is a discipline that can be fiercely competitive: There's a potentially enormous payoff for whoever makes the next major breakthrough -- yet such advances occur only a few times per century. Challenging accepted paradigms is rarely rewarded.
Pekka Sinervo, who served as chairman of the U of T physics department in the late 1990s, says Dr. Moffat's ideas "have been unorthodox and, in various ways, quite creative. The fact that he hasn't stumbled upon a revolutionary concept that clearly 'works better' doesn't take away from the impact his ideas have had. He has shown that many things that looked promising don't work. This has been hard work, and he hasn't received, in my opinion, the appropriate recognition for it."
In 2000, facing mandatory retirement from U of T, Dr. Moffat took a position at the privately run Perimeter Institute in Waterloo. The institute, housed in a heritage brownstone building nicknamed Space-Time Square, seems to invite unconventional thinking. Its second-floor lounge features plush sofas, games of chess and Go, a billiards table, plenty of chalkboards -- and a bar.
Here -- where everybody seems to have an unorthodox idea about the nature of the universe -- Dr. Moffat seems to fit right in. And he is as busy as ever.
He is trying to understand why two-thirds of the universe is made of "dark energy," a mysterious substance that seems to counteract gravity. He has even proposed a test to see if dark energy "falls" at the same rate as ordinary matter.
He is also trying to figure out how general relativity, which governs the behaviour of large objects, can be made compatible with quantum mechanics, which explains how matter and energy behave on the atomic and subatomic scale. That, in the minds of many researchers, is the outstanding issue in physics today. Of those who are currently trying to resolve the impasse, most are turning to string theory, a late-20th-century spinoff of particle physics, in which the most fundamental constituents of matter are not point-like particles but rather tiny, vibrating strings.
But Dr. Moffat -- no surprise -- has his own ideas. He has been developing what he calls "bi-metric gravity theory," an extension of the VSL scenario that tries to embrace both quantum mechanics and the geometry of space-time. It's a counterintuitive approach, but then, the universe, as physicists have discovered, is a very weird place that rarely shows any respect for human intuition.
As always, the physics community is divided between those who respect Dr. Moffat for his vision and hard work, and those who think he is tilting at windmills. And that, he says, is hardly surprising. Paradigm shifts, by their very nature, are few and far between.
"Physics is moved by ideas," he says. "But when you have new ideas, people get uncomfortable -- as they should, because you don't want to change a paradigm unless there's a really good reason to do so."
Dan Falk is a science journalist based in Toronto.