Over the course of her career Susan Scott has explored the fundamental question of how gravity relates to and shapes the universe. And, importantly, how we can formulate and discuss that force mathematically.

Today, the Australian National University Distinguished Professor has been presented with the Australian Mathematical Society’s George Szekeres Medal in recognition of these outstanding contributions to the mathematical sciences.

“I do feel very honoured to receive [the Medal], because it’s a pinnacle award for research in the mathematical sciences,” Scott, who is the third woman ever to receive the award, told Cosmos.

“This has traditionally been a male dominated field and to be a woman and receive it, it’s such a wonderful example to young women coming up through the field.

“Mathematics is great because it’s not just an academic thing. It underpins all kinds of occupations. It’s a fantastic skill to have.”

That skill led Scott to become an expert in the theory of general relativity, Albert Einstein’s theory of how gravity affects the fabric of space-time.

“I see what the implications are of that theory, like it predicts the formation of black holes, which is a type of singularity in space time,” she explains.

“I investigate how the theory leads to this type of singularity, and what the properties of these black holes and singularities are.

“I also investigate the sort of behaviour we have at the beginning and at the end of the universe. And that, again, it’s a very mathematical investigation but it’s motivated by a physical question.”

In the 1990s, Scott became involved in the quest to discover gravitational waves – ripples in space and time caused by massive cosmic events like the collisions of black holes and neutron stars. She was an Australian leader in the international team that first detected gravitational waves in 2015, contributing to the theoretical framework of how to analyse the data to differentiate gravitational wave signals from other signals in the universe.

“Every way we’ve been observing the universe prior to that was as part of what we call the electromagnetic spectrum. So, principally light. People have been looking up into the heavens forever,” she says.

“But the thing about gravitational waves is they do not belong to that spectrum, so it’s a completely new way of observing the universe.”

The first gravitational waves detected were produced by 2 black holes spinning around each other and eventually colliding to form a larger black hole. A system like that, which doesn’t give off light, is best probed by studying its gravitational waves.

In 2017, scientists detected the gravitational waves produced by 2 colliding neutron stars. Now Scott wants to reveal the secrets of neutron stars by detecting the much weaker continuous gravitational wave stream emitted by a single neutron star as it spins.

“What’s inside the neutron star, what’s powering it?” she asks.

“They’re the densest thing out there, not including black holes … and we really don’t have a great idea of how they tick,” she says.

She is also working towards completing the famous singularity theorems of Roger Penrose and Stephen Hawking, which were formulated in the 1960s.

“They show that under very general conditions on space time, an incomplete curve will form,” she explains.

“People have wondered ever since, well, what happens at the end of that causal curve? Are they actually finishing at a black hole? Because the name singularity theorem suggests they’re finishing at a singularity, like a black hole, but it’s not ever really been completed.

“They’re fantastic theorems, but in a sense, they’re incomplete. So, one of the things that I’m working on at the moment is completing those, which would be an amazing result if it comes to pass.”