Thinking is the most important part of Amanda Weltman's job, so where is her favourite place for it?
"A few years ago, when I was in a country that wasn't in the middle of a drought, it was the shower - the ideas tend to flow best there," says the theoretical physicist, who is based at the University of Cape Town.
"These days, though, it's when I'm driving alone, or lying with my kids when they fall asleep."
Weltman did her doctorate at Columbia University in New York under the supervision of Professor Brian Greene, director of the university's Centre for Theoretical Physics, whose bestsellers include The Elegant Universe and The Fabric of the Cosmos.
She is trying to unite two different areas of science: particle physics, the study of very, very small particles, and cosmology, which traces and probes the dances of stars and galaxies.
"That is where my niche is," she says, "bridging between ideas."
It was this ability to connect different ideas that catapulted her and colleague Justin Khoury - an associate professor at the University of Pennsylvania - to scientific acclaim with their 2004 paper Chameleon Cosmology.
The theory aims to explain the existence of dark energy, an area that baffles scientists along with the rest of us.
Dark energy makes up nearly 70% of the universe, but we cannot see it - we can only see how stars and other objects in the cosmos behave around it.
"We were trying to solve a problem in string theory," says Weltman, "and ended up seeing the connections between fields."
A MAN'S WORLD
Physics has traditionally been male-dominated, with few women becoming full-time researchers in the field, particularly in South Africa.
Weltman was the first woman to be brought into her research group at Columbia, and was her supervisor's first woman graduate student.
"In my area, women are rare," she says, but adds that she did not experience difficulties because of it...