Stephen Hawking (8 January 1942 – 14 March 2018) was an English theoretical physicist, cosmologist, and author. He was the director of research at the Centre for Theoretical Cosmology and previously the Lucasian Professor of Mathematics at the University of Cambridge. His scientific works included a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity and the theoretical prediction that black holes emit radiation, often called Hawking radiation. He was the first to set out a theory of cosmology explained by a union of general relativity and quantum mechanics, and was a supporter of the many-worlds interpretation of quantum mechanics. Hawking achieved commercial success with several works of popular science in which he discusses his own theories and cosmology in general, including his 1988 book A Brief History of Time.
Hawking was diagnosed with a rare early-onset slow-progressing form of motor neurone disease (also known as amyotrophic lateral sclerosis) that gradually paralysed him. He is pictured here in 2007 being rotated in mid-air while experiencing weightlessness in a reduced-gravity aircraft, a modified Boeing 727.Photograph credit: NASA / Jim Campbell / Aero-News Network