Bril­liant but unmo­ti­vat­ed, Stephen Hawk­ing was a 21-year-old PhD stu­dent at Cam­bridge when he first noticed some­thing was wrong. He was falling down a lot, and drop­ping things. He went into the hos­pi­tal for tests, and learned he had amy­otroph­ic lat­er­al scle­ro­sis, or ALS. The doc­tors told him he would grad­u­al­ly lose con­trol of every mus­cle in his body.

“My dreams at that time were rather dis­turbed,” Hawk­ing said. “Before my con­di­tion had been diag­nosed, I had been very bored with life. There had not seemed to be any­thing worth doing. But short­ly after I came out of hos­pi­tal, I dreamt that I was going to be exe­cut­ed. I sud­den­ly real­ized that there were a lot of worth­while things I could do if I were reprieved.”

The doc­tors gave the young man two and a half years to live. That was in ear­ly 1963. Over the next half cen­tu­ry, Hawk­ing defied all odds and went on to become one of the most cel­e­brat­ed sci­en­tists of the era, mak­ing major con­tri­bu­tions to quan­tum cos­mol­o­gy and the under­stand­ing of black holes. Along the way, the wheel­chair-bound Hawk­ing became a cul­tur­al icon, a sym­bol of dis­em­bod­ied intel­lect and indomitable spir­it.

This com­ing Sun­day, 49 years after his grim diag­no­sis, Hawk­ing will turn 70. A sci­en­tif­ic con­fer­ence in his hon­or got under­way today at the Uni­ver­si­ty of Cam­bridge’s Cen­tre for The­o­ret­i­cal Cos­mol­o­gy, and will cul­mi­nate on Sun­day with a pub­lic sym­po­sium, “The State of the Uni­verse,” fea­tur­ing some of the world’s great­est astronomers and physi­cists, includ­ing Mar­tin Rees, Kip Thorne and Saul Perl­mut­ter. You can watch live stream­ing video of the events at the offi­cial web­site.

To help cel­e­brate, we present Errol Mor­ris’s 1992 film of A Brief His­to­ry of Time (above), Hawk­ing’s best­selling book.  Mor­ris weaves biog­ra­phy in with the sci­ence, inter­view­ing mem­bers of Hawk­ing’s family–his moth­er, sis­ter and aunt–along with friends and col­leagues, includ­ing Roger Pen­rose, Den­nis Scia­ma and John Archibald Wheel­er.

A Brief His­to­ry of Time was Mor­ris’s first film as a direc­tor-for-hire (he was recruit­ed by Steven Spiel­berg for Amblin Enter­tain­ment), which cre­at­ed some dif­fi­cul­ties, but Mor­ris was pleased with the out­come. He lat­er said, “It’s actu­al­ly one of the most beau­ti­ful films I ever shot.” The film won the Grand Jury Prize for Doc­u­men­tary Film­mak­ing and the Doc­u­men­tary Film­mak­er’s Tro­phy at the Sun­dance Film Fes­ti­val.

In 1992 Mor­ris told the New York Times Mag­a­zine that A Brief His­to­ry of Time was “less cere­bral and more mov­ing” than any­thing he had worked on before. “This feel­ing of time, of aging, of mor­tal­i­ty com­bined with this search for the most basic and deep ques­tions about the world around us and our­selves,” Mor­ris said, “is pret­ty per­sua­sive stuff.” Find it list­ed in our Free Movies Online col­lec­tion, with­in the Doc­u­men­tary sec­tion.