Stephen Hawking, the preeminent physicist whose unmistakable voice and brilliant conjectures about the cosmos transformed our understanding of the universe, died at age 76 early this morning. Like Einstein, who was born on this day in 1879, Hawking’s name was synonymous with genius , curiosity, and a facetious sense of humor.

“Stephen Hawking leaves behind an extraordinary legacy as a scientist, a popularizer, and as a figure of courage,” cosmologist and theoretical physicist Sean Carroll told NOVA Next. “His work on black holes and the Big Bang left an indelible imprint on modern physics.”

Moreover, Hawking’s insight that black holes give off a tiny bit of radiation, now referred to as Hawking radiation, “bequeathed to the physics community a beautiful conundrum: if information falls into a black hole , how does it eventually escape back out? Decades later, some of the world’s brightest minds are continually struggling with this problem,” Carroll said.

“It is said that fact is sometimes stranger than fiction, but nowhere is that more true than in the case of black holes,” Hawking said at the April 2016 inauguration of the Black Hole Initiative at Harvard University, the world’s first institute dedicated to black hole research.

Especially in recent years, Hawking came to represent a sort of male Sybil: a scientist of such colossal stature that any proclamation from the seat of his wheelchair—where he suffered for years from Lou Gehrig’s disease—was experienced by many as a ripe, newfound truth.