The family of Stephen Hawking has confirmed his death at the age of 76.

A family statement to the Guardian reads, “He was a great scientist and an extraordinary man whose work and legacy will live on for many years.”

Hawking was easily the best-known scientist in the world for, according to BBC.com, “his groundbreaking work with black holes and relativity.” He also made a lot of mainstream appearances on shows like Star Trek: The Next Generation and The Simpsons.