Stephen Hawking was among the recipients at the White House today when President Barack Obama presented the National Medal of Freedom to 16 “agents of change.” Relatively few scientists win this medal, the highest civilian honor awarded in the U.S., particularly when the science is as removed from everyday life as the theoretical physics of black holes.

Hawking, of course, is no ordinary scientist, his wheelchair-bound figure having become an element of the zeitgeist (at least as measured by cameos in Star Trek and The Simpsons). Severely disabled for most of his adult life by a motor neuron disease (amyotrophic lateral sclerosis, or ALS), he has become emblematic of the human spirit pressing on against adversity. (In a Q&A on his web site, when asked about the study of physics taking him “beyond physical limitations,” Hawking answered, “The human race is so puny compared to the universe that being disabled is not of much cosmic significance.”)

In physics, his name is connected with proofs that the universe must contain “singularities” and with radiation theoretically emitted by black holes. The latter, Hawking radiation, led to a conundrum known as the information paradox in which black holes seemingly can obliterate information in a way that goes against a fundamental feature of quantum mechanics. Faced with two alternatives—the information is destroyed or not—Hawking bet (literally, with physicist John Preskill) on the information loss, implying that quantum mechanics would have to be overturned at a fundamental level. But in 2004 he conceded the bet, costing him a copy of the information-preserving volume, Total Baseball, The Ultimate Baseball Encyclopedia.

In April this year, a health scare put Hawking’s name in the news, when he was taken to hospital by ambulance after reportedly suffering breathing problems. Happily, in the Mark Twain tradition, rumors of an imminent demise proved unfounded.

Another scientist among Hawking’s fellow 2009 medal recipients is geneticist Janet Davison Rowley, cited for her “studies of chromosome abnormalities in human leukemia and lymphoma, which have led to dramatically improved survival rates for previously incurable cancers.” Economist Muhammad Yunus is also honored. In the November 1999 Scientific American, he wrote about the Grameen Bank, which he founded in Bangladesh in 1983 to provide microloans to the poor.

Past science winners includes James Watson of DNA fame, Francis Collins (who led the Human Genome Project, among other accomplishments) and the cold-war hawk, nuclear physicist Edward Teller.

Hawking’s citation plays up his role in popularizing science, through his bestselling A Brief History of Time and also children’s books co-authored with his daughter, Lucy Hawking. The citation concludes, “His persistence and dedication has unlocked new pathways of discovery and inspired everyday citizens.”

Image of Stephen Hawking in1999 from Wikipedia.