Mary Williams, New Zealand
When she was 14, Mary Williams already knew she wanted to be an astronomer. Now, at 34, she's a researcher at the Leibniz Institute for Astrophysics in Potsdam. She's trying to find out how galaxies develop.
This is an important question for cosmologists. She was looking for answers in our own galaxy, the Milky Way when she made a sensational discovery. She detected the remains of a dwarf galaxy that was evidently swallowed up by the Milky Way.