The director of the Vatican Observatory, Jesuit Father Guy Consolmagno, paid tribute to the astrophysicist Stephen Hawking, who died today at 76.

The scientist, a member of the Pontifical Academy of Sciences since 1986, had met Pope Francis in 2016.

“We mourn the death of Stephen Hawking, a scientist of admirable perspicacity, who was even extraordinarily capable of giving a human face to cosmology and astronomy,” said the Jesuit.

In the 1970s, the British astrophysicist had developed his own theory about black holes, which he says emit radiation. He also published A Brief History of Time in 1988, a book that intended to explain to the general public the great principles of cosmology. This book has sold more than nine million copies: an all-time record for a scientific book.

On November 28, 2016, the astrophysicist, a non-believer himself, met Pope Francis. He had declared that he did not believe in a creative act preceding the Big Bang, even if for him the universe was the fruit of “logic” and not chaos. The Sovereign Pontiff had meanwhile affirmed in 2014 that the Big Bang was “an act God’s love.”

Stephen Hawking was diagnosed with Charcot’s Disease at the age of 21, a paralyzing degenerative disease. He was almost completely paralyzed and unable to speak except through a vocal synthesizer.