Canada wasn't ready for unsung physicist Harriet Brooks — and it's our loss

Welcome time travellers! Inspired by the missing journal pages in Murdoch Mysteries: Beyond Time, we're exploring what Canada might have been like without a few extraordinary citizens.

There are shelves of books written about pioneering nuclear physicists Ernest Rutherford, Marie Curie and J.J. Thomson. There's only one comprehensive biography of Harriet Brooks, who worked with all three of them.

Her untold story caught the attention of an academic named Geoff Rayner-Canham, who noticed her while reading an old book called Discovery of the Elements. 

"It was illustrated by cameo portraits," says Rayner-Canham. "In among page after page of old males was a photo of an H. Brooks."

Geoff told Marelene Rayner-Canham, his partner and co-author, that it would be a nice summer project to find out more about her. That summer project grew into five years of research uncovering her crucial role in discovering the element radon, how radioactive elements decayed and a phenomenon called recoil.

Her research accelerated a field that has helped us develop nuclear fission, monitor radiation hazards in our own homes, and figure out how old the earth itself is — all at a time when women in sciences were encouraged to quit as soon as they found a husband.

Humble roots

Brooks was born in 1876 in Exeter, Ontario. She was one of eight children, who often practiced FHB or "Family Hold Back" if there wasn't enough food to go around. She entered McGill University in Montreal just a few years after it granted its first degree to a female student, and she helped ease the burden on her family by earning impressive scholarships.

After she graduated in 1898, she became the first female graduate student to work in Ernest Rutherford's pioneering physics research group at McGill.

Rutherford is well-known for his ground-breaking research in nuclear physics, but it's rarely acknowledged that he co-authored several studies in Canada with Harriet Brooks. She was his most valued researcher, and he put her to work puzzling out a mystery.

Radioactivity was still an extremely new concept, and Rutherford asked Brooks to figure out why it seemed like radioactive thorium was emitting some "emanation" that could be carried away on air currents.

Brooks made the crucial discovery that the mysterious gas was actually an undiscovered element: what we now call radon. Before this, scientists doubted elements could transform from one to another.

"She was very thorough, and that is what made her contribution so important," says Geoff Rayner-Canham. "Others would probably have ignored these odd results of radioactivity."

"So without Brooks, it may have been years before radon was discovered."

Radon is now known to be a common presence in homes and workplaces, which can lead to lung cancer. It's used today as a natural tracer to discover sources of groundwater.

Brooks also discovered that radioactive elements decay from one into another, and then another, in a predictable chain called a decay series. These predictable transformations are used today to date ancient rocks and fossils. Geoff and Marelene Rayner-Canham argue that without Brooks, it would have been years before anyone else made this discovery.

Forced to choose

There were very few opportunities for women in sciences at the time. Observant and adventurous, Brooks taught and studied physics in the United States, worked with J.J. Thomson at Cambridge and worked in Marie Curie's lab in France. But more than once, she was forced to choose between a career or a marriage.

The first time Brooks got engaged, her dean at Barnard College demanded she resign as a teacher and tutor. Brooks refused, writing, "it is a duty I owe to my profession and to my sex to show that a woman has the right to the practice of her profession and cannot be condemned to abandon it merely because she marries."

Ultimately she called off both that engagement and her position.

When Frank Pitcher came courting her in 1907 though, she decided to choose marriage over physics. Rutherford had recommended her for a fellowship in the U.K., but she saw the writing on the wall.

At 31, she stopped working as a researcher and returned to Canada to raise a family.

Harriet Brooks hit the "uranium ceiling" for women in physics, but it was an impressive life for a woman from Exeter with humble beginnings. She accomplished more in her short career than others do in a lifetime.