As a child, Jearl Walker wanted to be a chemist. He pored over chemistry books and had a lab in his family’s garage. Then he went to MIT and took his first chemistry exam. 

"I got one point above an F," he says. "So I thought that was a message from God—'Make other plans.'"

Luckily, one was waiting. In high school, Walker had become fascinated with modern physics, staying up late to read about Feynman diagrams, which explain that antiparticles are normal particles going backward in time. "And I thought, Wow, this is not science fiction—this is Feynman saying this."

Later, facing a dubious future in chemistry, Walker knew what his next step should be. "I said to myself, OK, let’s go do the fascinating stuff. Let’s do physics."

During graduate studies at the University of Maryland, Walker received a postcard that would change the trajectory of his career. 

He had become a teaching assistant, and one day a student questioned what physics had to do with her life. "This is the fundamental fabric of the universe," he told her. "It has everything to do with your life." 

But when challenged to find an example on the spot, he struggled. That night, he began a project that would become the book The Flying Circus of Physics, initially a compilation that addressed questions like, Why is the sky blue? 

As Walker received more and more requests for his compilation from students and faculty, he had it printed as a technical report. Then a colleague suggested he send the report to Philip Morrison, a physicist who had worked on the Manhattan Project alongside J. Robert Oppenheimer. 

At the time, Morrison reviewed books for Scientific American. "I was just a graduate student," Walker says.
But he sent Morrison the report. A few weeks later, a postcard arrived. Morrison gave Walker more ideas for his collection, then wrote, "Publish!"

"That gave me the courage to send the report out to book publishers," Walker says. After receiving interest from editors, Walker sought the advice of Robert Resnick, coauthor with David Halliday of The Fundamentals of Physics, a textbook Walker had been using since his undergraduate days at MIT. "I think I called him collect," he says.

Resnick advised Walker on which publisher to choose, and when the book came out, Morrison reviewed it for Scientific American. He also suggested that the publication hire Walker to continue its amateur scientist column, for which Walker would write 4,000 words a month for more than a decade. 

Halliday and Resnick tapped Walker to take over when they retired as authors of The Fundamentals of Physics. He did so in 1990—and continues the work to this day. His editions have sold millions of copies, and because of his books, Walker has been featured in numerous print publications and on TV and radio. 

"Everything happened because of that one postcard," he says. Walker even credits The Flying Circus of Physics for making him a standout candidate for a position at Cleveland State University (CSU) right after graduate school. More than 50 years later, he’s still a professor of physics at CSU and has taught both the children and grandchildren of former students. "I’m always looking for new ideas and things to pique interest," he says of teaching. "Sometimes students come back later, maybe even years later, and thank me—and that’s very rewarding."

At an induction ceremony in 2023, Walker was awarded the rare distinction of Sigma Pi Sigma honorary membership "in recognition of his many years of supporting countless students across many countries through hundreds of articles and presentations, his seminal contributions to introductory physics courses, and defining how physics is the clockwork of the universe to generations of students."

The honor puts Walker in the company of Linus Pauling, Jocelyn Bell Burnell, S. James Gates Jr., and other distinguished physicists and astronomers. "They read off the names of people who have received that honor before, and I said, 'Gosh, I’m not among that crowd,'" Walker says. "Me and Linus Pauling? I don’t know about that."  

His many readers and students likely feel differently.  

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