Senior lecturer: Department of Mathematics and Applied Mathematics, University of Cape Town

“I study the big questions — how the universe began and how it will end,” says 33-year-old Amanda Weltman. Paradoxically, the keystone of her major contribution to physics is a tiny particle we’re yet to spot on Earth.

Weltman completed her BSc in physics and applied mathematics and honours in theoretical physics at the University of Cape Town (UCT). A series of scholarships took her to Columbia University in New York, where she advanced to her PhD. While in the US Weltman also took up a teaching fellowship at Columbia and won a research fellowship from Nasa. In 2007 she received a postdoctoral fellowship to the Centre for Theoretical Physics (then headed by Stephen Hawking) at Cambridge University.

Weltman’s signature breakthrough came at 24, when she proposed a model based on the idea of dark energy, the esoteric entity scientists believe causes the ever-quickening expansion of the universe. “Chameleon” dark energy was Weltman’s explanation of how this happens. She argued that “the particle responsible for this acceleration should interact directly with all matter types”, the upshot being that the particle’s behaviour must vary along with its environment, like a chameleon. And that’s where it gets galactically complex.

What is the point of this far-out ingenuity? For starters: “It’s really amazing to apply just the powers of the brain and arrive at a greater understanding of the universe,” says Weltman. But she hastens to add that “the applications of pure science are enormous”, pointing out how Einstein’s theories led to tools we use every day, such as lasers and GPS devices.

Having returned to UCT in 2009 to research and teach, Weltman continues to impress. Recent accolades include the 2009 National Women in Science award for best emerging young researcher, and the Royal Society of South Africa’s Meiring Naudé medal for young scientists in 2011.

— Ian Macleod

YouTube: Amanda Weltman