Stephen Hawking, the British cosmologist famous for his work on black holes and for surviving and thriving with amyotrophic lateral sclerosis for half a century, has died at age 76.

His key discoveriesThat the Big Bang started from a singularity (i.e., it was a black hole in reverse); that black holes aren’t totally black but radiate energy and eventually evaporate; and that quantum fluctuations in the early universe could have led to the clumping of galaxies we see today.

On his ALS: “I have lived with the prospect of an early death for the last 49 years. I’m not afraid of death, but I’m in no hurry to die,” he wrote in 2010.

On why he lived so long: Partly good care, but mostly sheer luck. “He’s certainly an outlier,” explained an expert on the disease.

In his own words: For a summary of his work, listen to the BBC Reith Lectures he delivered in 2016, or read the transcript.

On his synthesized voice: It was made by Intel, after he met the company’s founder, Gordon Moore, at a conference. Intel later open-sourced the platform so others could build on it. This online version of the synthesizer will speak any words you type into it.