In 1963 a 21-year-old man was ice skating with his mother when he fell and found himself unable to get up. He visited the doctor, was diagnosed with amyotrophic lateral sclerosis (ALS) and told he had two years to live.

With the nerves that controlled his muscles shutting down, Stephen Hawking fell into a deep depression — even considering dropping his studies altogether. But within a year he had established a reputation for brilliance, challenging the work of prominent Yorkshire astronomer Fred Hoyle in a June 1964 lecture.

Hawking would go on to defy his diagnosis, living more than half a century beyond his life expectancy and becoming one of the most iconic scientists of all time. His work broke new ground in our understanding of black holes, expanded on Einstein’s theories about space-time, and set out a new theory of cosmology. In the duration of his life Stephen Hawking not only furthered our understanding of the universe, but increased public engagement with science and advocated powerfully for political change.