John Moffat honoured for lifelong pursuit of physics

It takes a certain kind of bold thinking, combined with careful dedication to challenging assumptions, to advance new ideas in fundamental physics.

There is perhaps no one more emblematic of this philosophy than John Moffat who, at 93, just received a letter from Prime Minister Mark Carney congratulating him on a lifetime of scientific achievement.

“Your pioneering research widely influential both in Canada and abroad has significantly advanced fundamental science and strengthened Canada’s position as a leader in theoretical physics,” Carney writes.

Born in Denmark in 1932, Moffat has spent much of his illustrious and storied career swimming against mainstream ideas. It’s a career that spans seven decades and touched some of physics’ most famous characters. His 2010 memoir Einstein Wrote Back details his most famous contact, a months-long correspondence with the creator of general relativity. But Moffat also shared an office with Niels Bohr, clashed with Oppenheimer, took classes with Dirac, and encountered many, many more.

Reading the letters today, one line from Einstein seems to set the course for Moffat’s career. Moffat had written to Einstein after his very first scientific talk, given to Niels Bohr and his associates. The talk did not go over well, and Einstein offered Moffat support. “Every individual and every study circle has to retain its own way of thinking if he does not want to get lost in the maze of possibilities,” Einstein wrote of Bohr.

Moffat spent the next 70 years passionately exploring that “maze of possibilities.” 

A dedication to outside of the box thinking

Perhaps one reason for Moffat’s bold approach grew out of his own unconventional journey into physics. He spent his childhood in war-torn Europe, moving from Denmark to Scotland to England. In his teens, he dropped out of school and moved to Paris to study abstract expressionism. After a year and little success, he moved back home to Copenhagen to help support his family.

It was here that Moffat discovered physics at the local library. He had a natural aptitude for the subject, and soon started writing letters to physicists, which is where his correspondence with Einstein began.

His letters from Einstein helped him contact Bohr, who invited Moffat to give that infamous talk. Bohr introduced Moffat to Schrödinger, who wrote him a letter of reference to Cambridge. Surprisingly, they accepted Moffat into their Ph.D. program, making him the first Ph.D. student at Trinity College, Cambridge, to be admitted without an undergraduate degree.

After graduating, Moffat found work in the United States and ultimately ended up at the University of Toronto in 1964. He spent nearly forty years at Toronto until he retired in 2001, working primarily on alternative models of gravity. Among other things, Moffat looked for an extension that would unify its fundamental forces. He later detailed this work in his 2008 book Reinventing Gravity: A Physicist Goes Beyond Einstein.

When he retired from U of T, Moffat still had research to do, and bold ideas to pursue. So he moved to Waterloo, and Perimeter Institute when it was still in its infancy, nestled in an old post office building down the street from its current campus. He has been a mainstay at Perimeter ever since, writing books on his unique approach to gravity, the Higgs Boson, and publishing research papers in respected journals.

New ideas and new horizons

Perhaps because of his unique entry into physics, or his contact with many of the legends of field, Moffat established a pattern in his early research that holds true 70 years later: poke at central assumptions in major theories and see what happens.

“I construct an alternative (of mainstream ideas),” Moffat said in an interview in 2010. “I take the norm and turn it inside out.”

Take, for example, his variable speed of light (VSL) theory. Those familiar with Einstein’s relativity will know that its central idea is that the speed of light is constant.

Moffat asked a simple question with major consequences: what if the speed of light had changed since the early universe? What would that mean for gravity? For the history of the universe?

Moffat published a paper on VSL in 1992, where it received little attention until 1998, when another team of physicists independently published a similar idea in Physical Review D A subsequential book by one of the coauthors dedicated an entire chapter to Moffat’s contribution.

It’s a pattern Moffat has seen throughout his career: he challenges a central idea with a paradigm shift, only for that same idea to come into the mainstream years later. It’s why he is amongst the top 0.05% most-cited researchers on ScholarGPS, a scholarly works analytics site.

Another instance of this approach is in Moffat’s modified gravity (MOG) theory, also called scaler-tensor-vector gravity. MOG keeps the spacetime curvature Einstein explained in general relativity, but adds one extra vector field and several scalar fields.

These extra fields make the effective gravitational strength vary at the scale of galaxies and galaxy clusters, and produce an additional, short‑range repulsive “fifth force.” The effect: an explanation of gravity that does not require existence of dark matter.

The theory is not without its detractors, which Moffat expects and even welcomes. “It is almost a given that new ways of seeing nature face severe opposition,” he writes in Einstein Wrote Back. “This is not entirely a bad thing because a paradigm in science should not be changed until a new one has been thoroughly tested over time and survives. There’s a built-in conservative attitude in scientific research, which is as it should be.”

At 93, John Moffat is still contributing to the scientific community, pursuing unique ideas about gravity, particle physics, the early universe, and more. His long and influential career has seen the flourishing of many different ideas, but a singular methodology: look at things differently, challenge assumptions, and do physics differently.