Tributes have been pouring in from around the world for one of the world's greatest scientists, Stephen Hawking, who has died at the age of 76. Although he was well-respected in scientific circles early on, the physicist gained global acclaim in 1988 for his book, A Brief History of Time, and garnered such cultural influence that he was given guest-starring roles in Star Trek and The Simpsons.

Al Jazeera's Nadim Baba looks back at the life of the man who many consider changed our understanding of the universe.