Abraham (Avi) Loeb is a theoretical physicist, author, and Harvard professor. He was the longest-serving chair of Harvard's astronomy department (for nine years) and is an elected member of the American Academy of Arts and Sciences, the American Physical Society, and the International Academy of Astronautics. Loeb is a member of the President's Council of Advisors on Science and Technology at the White House and, in 2012, TIME magazine selected Loeb as one of the 25 most influential people in space.