21. Fabiola Gianotti, Particle scientist, Cern selected Nima Arkani-Hamed, Theoretical physicist

At Princeton's Institute for Advanced Study, Nima is one of the most outstanding theorists in fundamental physics, in spite of his young age. For instance, he has proposed ground-breaking ideas to reconcile gravity with the other forces. He is not just a brilliant thinker but also lively, full of ideas and energy, and has a good sense of humor.

22. Leila Janah, Founder, Samasource selected Robyn Scott, Cofounder, OneLeap

“She figured out the best way to affect Aids in Botswana was to tell a story that would compel people to act. The story in her memoir Twenty Chickens for a Saddle was hers, but it was motivated by interest in others,” said Leila.

23. Aza Raskin, Entrepreneur selected Tom Coates, Technologist

Coates is a surly Englishman who has a rare mix of design ability and future-think. He was one of the earliest bloggers. He has predicted and embodied the blog revolution, location services, and the internet of things. He will soon change the way we think and understand cities.

24. Graeme Le Saux, Broadcaster selected Vanessa Berlowitz, Series producer, BBC

Vanessa is responsible for programmes such as Planet Earth and Frozen Planet. Her dedication of using technology such as aerial and time-lapse photography has revolutionized the way we view and understand the natural world. She is shaping the thoughts of the viewing public and thus, motivating them to protect the natural environment.

25. David Deutsch, Quantum physicist selected Hagar Gelbard-Sagiv, Scientist

Research into aspects of human brain function is extremely important and is going to expand swiftly as technology progresses. “But it's an area that is prone to being led down blind alleys by bad philosophy. I'd want to grill Gelbard-Sagiv on whether she understands the role of philosophy in fundamental science, and whether she gets it right,” said David.