Katie Mack: Exploring gravity in mind and body

As a cosmologist who explores the distant past and future of the universe, gravity is one of Katie Mack’s professional obsessions; as an aviator, gravity is her favourite dance partner. 

“You know, I didn’t really expect at this point in my life to find a new all-encompassing passion,” she says, “but I just am so excited about aviation. I love being in the sky. It’s become really half of my life, along with physics on one side and then flying on the other.”

What started as a pandemic boredom buster — flight school — became an essential facet of Mack’s life once she felt the thrill of the open skies. When flying, she can feel gravity in novel ways; with physics, she can explain gravity in novel ways. 

On terra firma, Mack holds the inaugural Hawking Chair in Cosmology and Science Communication, and she’s determined to honour its famous namesake. She splits her time, as Stephen Hawking himself did, between doing physics and explaining physics to non-scientists who are fascinated by it. 

That duality suits her perfectly. As a cosmologist, she studies the fundamental structure and fate of the universe. As a communicator, she translates those abstractions into messages people can feel. She is the creator of Quantum 101 and Cosmology 101, Perimeter video series explaining fundamental physics concepts with the clever metaphors and simple explainers that made her one of the most followed scientists on social media.

Talking about science – and especially writing about it – has always come naturally to her. 

“I’ve always really enjoyed writing,” says Mack, who grew up in California. “When I was a little kid, I would write stories and poems and things like that. It’s hard not to talk about something when you’re excited about it. It’s just fun for me to be able to share what’s really, really cool about what we’re learning about the universe.”

Her passion for science is obvious when she speaks to groups of people, which is often. She has given numerous public lectures at Perimeter and around the world. She coordinated the Scicomm Collider, a gathering at Perimeter of many of the world’s most popular science communicators, which resulted in public talks by voices like Stephon Alexander and Clara Nellist. 

It’s not a coincidence that her chair bears Stephen Hawking’s name. “I’ve known about Stephen Hawking since I was a little kid,” she says. “I was very young when I first read A Brief History of Time. I was fascinated by all these ideas about space, time, the Big Bang, and black holes. “Throughout my career, I was fortunate to be in some of the same places as him, even in similar research groups. It’s fun to have a position that’s named after somebody who was such an inspiration to me. It’s named after Hawking because Stephen Hawking did an amazing amount to popularize cosmology — to share his research with the world and help people understand what we knew at the time and what we’re learning about how the universe works.” 

Mack’s own research about the universe spans, well, everything. 

“Over the course of my career, I’ve worked on early-universe physics — really the beginning, the process of the Big Bang, cosmic inflation, what started off everything that we see today,” she says.

“I’ve also worked on the way the universe evolved from the beginning to today — the process called reionization, when the stars and galaxies turned on and changed the state of the gas within the universe. And I’ve been doing a lot of work on dark matter — trying to understand how dark matter might have affected the first stars and galaxies in the universe.”

Her first book, The End of Everything: Astrophysically Speaking, was praised by critics and readers for its clear, funny and sometimes scary explanations of how the universe may end. She is currently writing another book that, with similar audacious ambition, aims to explain all of reality at the particle scale. 

She tackles such enormous challenges because they’re enormous — the greater the mystery, the more insatiable her curiosity. 

“Humans are curious. Humans want to know. That’s part of what drives this place. We’re doing this work because humans want to know, because we are a fundamentally curious species and we have to explore.”

It’s that same curiosity that draws her into the cockpit. There’s always something new to learn, some new challenge with a new accompanying reward. 

“One of the things that I really love about flying is that it really requires all of your focus,” she says. “When I’m flying, I really have to focus. I cannot be thinking about work. If I am thinking about work, I might crash.”

Flying, for her, is a mental cleanse — a state of absolute presence. “Sometimes you get that moment,” she says, “when you’re just there in the sky and you’re looking at the world and nobody else is there with you. And it’s kind of a beautiful thing — in the clouds, kind of these giant cloud canyons. Just a view you don’t get any other way.”’

At work and at flight, she is always searching for a clearer view of infinity.