For a few moments, one of the world’s foremost experts on gravity was free of it. His smile -- and his eyes -- couldn’t have been brighter.
It's an iconic image. Physicist Stephen Hawking -- world famous for expanding humanity's understanding of the cosmos -- floats in midair, free of gravity's pull.
The picture was snapped in 2007 while the scientist was aboard a "zero-G" airplane flight.
On that flight with Hawking was scientist Joshua Boger. He's a Wesleyan graduate and the former chair of the university's board of trustees. Boger also founded Vertex Pharmaceuticals.
Boger sat directly behind Hawking on that flight, which tracked out over the Atlantic, dipping up and down in the sky to provide its passengers with eight brief windows of weightlessness.
“He was beaming, his cheeks were as high as I'd ever seen them. And he was just in, what looked like, ecstasy,” Boger recalled. “We were all, of course, mesmerized, staring, at Professor Hawking.”
Boger, who had been on weightless flights prior to the one with Hawking, said you don’t really understand gravity until someone takes it away and puts it back.
“And that's what I thought he was thinking,” Boger said. “This person who understood, in detail, the equations of gravity, and took those equations to places that no one else had imagined ... he was so joyful because he apprehended gravity for the first time.”
Hawking was the best-known theoretical physicist of his time. His body was attacked by ALS -- also known as "Lou Gehrig's disease" -- when he was 21, but he stunned doctors by living with the usually fatal illness for more than 50 years.
Hawking died Wednesday. In a statement, his children Lucy, Robert, and Tim called him “a great scientist and an extraordinary man whose work and legacy will live on for many years.”
“It’s very easy when we’re around in the time of great people to think of them as ‘pretty good,’ but maybe not as great as some of the famous people we learned about in books,” Boger said. “But this was a guy who was every bit as great anyone else you’ve ever heard about.”
This report contains information from the Associated Press.