Who Was Carl Sagan?

Scientist

"He worked very hard, 18-hour days. He had a tremendous appetite for his work," says Poundstone. "He was made for television, sure, and he looked very relaxed and normal in jeans when other scientists didn't. But there was a lot more to him."

As a scientist, Sagan made a real mark on planetary science in the early 1970s as a young Harvard professor, "at a time when planetary science was a bit of a backwater," Poundstone says.

Sagan first predicted that the greenhouse effect made the atmosphere of Venus hot enough to melt lead, at a time when some scientists still speculated that its clouds might hide oceans, says Morrison.

Sagan also identified dark-shaded regions on Mars as highlands and identified lighter areas as desert plains marked by dust storms. Those storms later bedeviled NASA's Mars Viking landers in the 1970s.

"He was a really great big-picture scientist, great with back-of-the envelope calculations, who could see the fundamental premises of science and observations," says Morrison.

On the two Voyager missions launched in 1977 to explore Jupiter, Saturn, Uranus, and Neptune, Sagan was a member of the imaging science team. "That was really before the crest of his fame," says Morrison, a former student of Sagan's. "He was not a superstar then, just one of us."

Celebrity

Sagan led the team that put together the "golden records" attached to the Voyager mission's two spacecraft. The records (sent along with phonograph needles) included cuts of everything from Bach to "Johnny B. Goode," along with greetings and natural sounds from Earth.

To a large extent, Poundstone says, Sagan benefited from filling a scientific niche, planetary science, that was set to explode with new knowledge as a result of NASA's line of planetary probes exploring the solar system starting in the 1960s.

Reporters gravitated toward Sagan on those missions, Poundstone says. "They knew who could explain things." Sagan ended up as a regular on the Tonight Show (as Tyson now is on Comedy Central's Colbert Report), a guest favorite of Johnny Carson.

Parodied by Carson for his consonant-rolling pronunciation of "bill-ions and bill-ions" in the series, Sagan indeed thought big, even opening a line of Cosmos-themed stores that anticipated the museum-themed stores in malls today.

After the 1980 publication of Cosmos and the premiere of the PBS series, "things changed for Carl. He was getting death threats; he had to travel in limousines and keep a closed schedule," Morrison said. "People don't remember that."