Stephen Hawking died last week. Lots of tributes in the media about his scientific legacy and life.

Sean Carroll posted an article on his blog on March 16: “Stephen Hawking’s Scientific Legacy.” It’s particularly interesting. As a career physicist and cosmologist, Carroll met and interacted with Hawking over the decades. Early in his career Carroll turned down a job offer from Hawking twice.

Stephen Hawking is the rare scientist who is also a celebrity and cultural phenomenon. But he is also the rare cultural phenomenon whose celebrity is entirely deserved. His contributions can be characterized very simply: Hawking contributed more to our understanding of gravity than any physicist since Albert Einstein.

“Gravity” is an important word here. For much of Hawking’s career, theoretical physicists as a community were more interested in particle physics and the other forces of nature — electromagnetism and the strong and weak nuclear forces. “Classical” gravity (ignoring the complications of quantum mechanics) had been figured out by Einstein in his theory of general relativity, and “quantum” gravity (creating a quantum version of general relativity) seemed too hard. By applying his prodigious intellect to the most well-known force of nature, Hawking was able to come up with several results that took the wider community completely by surprise.

Carroll includes some useful links in his article for more information, including a podcast story about the time he picked up Hawking at the airport. Comments on Carroll’s post also are interesting.

Hawking died on Pi Day and the 139th anniversary of Albert Einstein‘s birthday. Einstein also died at the age of 76.