Theoretical physicist and mathematician Freeman Dyson (2nd, L) speaks at the "StarShot" project press conference at One World Observatory in New York, the United States, April 12, 2016. Attendees are (R to L): former director of NASA's Ames Research Center Pete Worden, NASA astronaut Mae Jemison, theoretical physicist Avi Loeb, author and producer Ann Druyan, theoretical physicist and mathematician Freeman Dyson and astrophysicist Stephen Hawking. British astrophysicist Stephen Hawking announced here Tuesday he is teaming up with Russian billionaire Yuri Milner and a group of scientists for a new "Starshot" space exploration program, which will build tiny spacecraft called "nanocraft" capable of reaching the Alpha Centauri star system in approximately 20 years after launch. (Xinhua/Li Changxiang)