Where are all the Black astronomers and physicists? Racism, isolation keeping many away

Canadian astrophysicist Louise Edwards is used to answering some of the universe's toughest questions. But at the moment she's trying to answer this one: How many Canadian Black astronomers does she know?

Edwards, an associate professor in California Polytechnic State University's physics department, is on a Zoom call with CBC while sitting in a friend's brightly lit shed near her home in Berkeley, Calif. 

Mulling the question, she turns her head to the right, facing white wood-panelled walls. She's thinking hard.

"Ummm," she says, looking off into . . .