William Kenneth Hartmann

William K. Hartmann
Hartmann being interviewed in 1998
Born	(1939-06-06) June 6, 1939 (age 85) New Kensington, Pennsylvania, U.S.
Alma mater	Pennsylvania State University University of Arizona
Awards	G.K. Gilbert Award, Carl Sagan Medal for Excellence in Public Communication in Planetary Science
Scientific career
Fields	Planetary science
Institutions	Planetary Science Institute

William Kenneth Hartmann (born June 6, 1939) is a noted planetary scientist, artist, author, and writer. He was the first to convince the scientific mainstream that the Earth had once been hit by a planet sized body (Theia), creating both the Moon and the Earth's 23.5° tilt.^[1]