Pioneering Canadian astrophysicist Sara Seager has spent much of her life searching for proof that we are not alone in the universe.

Even as a child, Seager was never satisfied with Earth. When she escaped the light pollution of Toronto and got her first real glimpse of the stars on a camping trip, she was captivated. For her, those pinpricks of light in the limitless sky represented possibility, a ticket to worlds bigger than her own.

Seager is now at the forefront of the search for Earth-like planets outside of our solar system that may support life. Her new memoir, The Smallest Lights in the Universe explores her journey through a complicated childhood, falling in love on an epic canoe trip through Canada's north, becoming a planetary scientist at MIT and losing her husband to cancer.

Through it all, Seager's sense of wonder and her desire to explore the unknown inspired her search for new worlds. She is, in the words of the New York Times, "the woman who might find us another Earth."

The Sunday Edition's guest host Kevin Sylvester spoke to Seager about her life and what drives her to keep searching the stars.

Here are highlights from that conversation, edited for clarity and condensed.

My first memory of the stars is stepping out of the tent in the middle of the night while camping and looking up. I saw so many stars. It was a moment of pure astonishment. I was so shocked that those that existed and I just remember thinking, "Why hadn't anyone told me about this?" It was so incredibly stunning. It's such a joyful thing to have that sense of discovery. And I still have that over and over again with my work. Even if someone else has discovered it or it's already known, to be the person to see something for the first time for yourself, it's always a big deal.

I did come from a broken home, my parents divorced when I was quite young and my mother moved to the city. We moved to this old rooming house. It was tough there. Later on, she remarried, and my stepfather was a monster. He was viciously and continually mentally attacking me. So I sort of had to kind of just tread water, struggle to survive.

The stars were an antidote to that because they gave me a sense of perspective, a sense of peace and of a calming envelope to know that there is something so far beyond us, so big, so vast, so mysterious, that our everyday troubles perhaps aren't so critical. One day when I was 16, there was a university-wide open house at the University of Toronto and the sign said "Astronomy Department." It was like a ginormous 'Aha!' moment because I realized that I could be an astronomer for a job, and that was definitely in the top 10 days ever of my life.

After I finished my undergrad at U of T and before I began graduate school at Harvard, I wanted to explore Canada's North. It was just absolutely incredible to be away for two months where there is virtually no one, unless you bump into another canoer. There was really nothing there, just the elements, the huge lakes, the vast open tundra and lots of caribou.

When I'd planned this trip, I didn't have anyone to go with because I don't really get along with people that well. And to go with a group of people or another individual on a trip like that, that has incredible challenges and where there's going to be big, unexpected things happening, it has to be someone you can work well with. But through a wilderness association I was a part of, I became close with my canoe partner, Mike.

We just shared our love of the outdoors, our love of adventure, of the unknown and of just sheer exploration. If you can get along with someone that well on a trip, it's a fantastic sign for life.

My book title, The Smallest Lights in the Universe, actually refers to the search for planets like our own. It's easier to find crazy big "Hot Jupiters" or "Warm mini-Neptunes" out in deep space, we even have "Hot super-Earths." But to find a true Earth twin, one like ours, around a star like our sun, the light coming from those exoplanets is so faint and so small. Those are the ones I call the smallest lights in the universe.

My life revolves around finding these exoplanets because I'd like us to know that we're not alone in the universe, to know that there's another place like ours, with oceans and continents, one that even we could call home. We can't see these possible Earth-like exoplanets yet because they're shrouded by the intense light of their stars, but we have a plan and it's called Starshade.

Starshade is a giant, specially shaped screen in a giant sunflower shape, about 30 metres in diameter. It would have a spacecraft attached to it and would fly into outer space, far from Earth's gravity. Starshade's giant screen would block out the starlight so that a space telescope would be able to see very faint planets orbiting a star.

It's like if you want to take a picture on a snowy day of a friend who's surrounded by tons of snow. What happens is you can't take the perfect picture because it's either completely over-exposed or completely under-exposed because the snow is so bright and the person is so dark that it's very hard to get a picture. It's the same with these exoplanets and their stars.

Being a scientist, it takes a certain obsessive nature to do a great job, you just get so wrapped up in the problem and you just really focus on it. And the book describes how we drifted apart. Mike and I had a very extended "honeymoon phase." We lived together without children for quite a long time. But once you have children, they take a lot of effort and it kind of divides your attention away from your partner. I was so ambitious, traveling a lot and working so hard, I didn't always give Mike the time and attention he deserved. And then he was diagnosed with cancer.

It was a roller-coaster. You go through chemotherapy, wait for the results, find out what they are and go through chemo again. There was one point where he had finished chemo and the doctor told us that he was going to be fine and that it looked like there was good news. We were ecstatic. We realized together we had another chance to stop drifting apart and to come back together.

We had 10 perfect, beautiful days together when the doctor called back and said he was wrong, new tumours that showed up were cancer. And this meant that he [Mike] was terminal.

I was so surprised that a group of young widows existed in the tiny city I live in and I went to their first meeting, which was on Valentine's Day. I was so nervous because usually when people start things like that by asking you what you do for a job, and if I say astrophysicist, it's a showstopper right there. But fortunately, no one asked me what I did. The widowhood, the grief, the struggle, the emotional angst is what brought us together. And I finally had something in common with some other women. It was so sad, but so amazing at the same time. The widows helped me through so many things, both practical, and just having a group of people to hang out with who had the same struggles I did.

Now everyone knows, not just me, that life can change in the blink of an eye. We saw that with a pandemic, all of a sudden everything got shut down and our world got turned upside down. I know for some people who lost their jobs, it's an incredible struggle and especially for people whose loved ones are dying. But I think the words of advice I can offer are to reassure yourself that things can get better and to take opportunity when it arises, and to be open to possibilities.