What would be considered a star-studded cast in the world of chemistry converged on the Physical Sciences Lecture Hall October 22 to rename the structure after the late pioneering U.C. Berkeley chemist, George C. Pimentel, who taught thousands of students in the hall.

Nearly 1,000 turned out at the dedication to hear the Pimentel Lecture, given by renowned astronomer and author Carl Sagan, who interacted with Pimentel while working on the Mariner missions to Mars.

Preceding Sagan's lecture, Professor Kenneth Pitzer, Pimentel's research director, spoke about Pimentel as a promising young scientist, while Professor Bradley Moore, Pimentel's graduate student and colleague, discussed his early achievements.

"George was really the quintessential teacher-scholar," Moore said.

Jan Coonrod, Pimentel's daughter, told the audience about Pimentel's unique personality and love for life. Vice Chancellor Carol Christ then performed the official dedication, saying that Pimentel, "in his life and in his career, epitomizes the ideal that Berkeley strives for."

Sagan's lecture, "Organic Chemistry in the Outer Solar System: Clues to the Origin of Life," blended Pimentel's achievements in chemistry with Sagan's own interests.

Sagan pointed out the use of Pimentel's infrared spectrometer as a key piece of analytical apparatus on the Mariner mission. Although his initial observations of the Martian atmosphere were in error, Pimentel's approach "has borne fruit repeatedly," Sagan said.

Profiling the use of infrared spectrometry in the discovery of organic chemistry in the solar system, Sagan recalled "George's sense that in space there ought to be lots of organic chemistry," adding that this has been confirmed with next-generation infrared spectrometers.

"Jovian planets and those beyond are loaded with organic chemistry," he said. Recently, Pimentel's technique was used to confirm the existence of organic material coming off Halley's Comet.

Sagan then focused on the chemistry of Titan, Saturn's largest moon. He and his colleagues managed to roughly reproduce the atmospheric conditions on Titan, deriving a substance that resembled the murky material observed on the surface of the planet.

"It is fair to claim that we bottled the haze of Titan," Sagan said. The haze, which left a "tarry, brownish solid" residual, had a spectrum that essentially matched measurements of Titan's spectrum. When analyzed, it was found to contain one percent amino acids and detectable amounts of polycyclic aromatic hydrocarbons.

"It is clearly loaded with great stuff," Sagan said, referring to the fact that such material suggests the possibility of life.

However, Sagan pointed out, Titan is essentially a frozen planet. Taking into account the heat generated by asteroid impacts, Sagan and his colleagues calculated that an average point on Titan has seen liquid water for about 1000 years in the last 4.5 billion years.

"Whether 1000 years is enough for the origin of life is very much an unknown question," said Sagan.

Nevertheless, Sagan said it is "at least very plausible that there is an organic chemistry accumulating on the surface of Titan that may be relevant to the origin of life."

Noting that the European Space Agency's mission to Saturn will carry a spectrometer not much different in principle from Pimentel's, Sagan concluded:

"George Pimentel's legacy will be in the Saturn system in the year 2004 and I think we can safely predict that in the entire future of spacecraft exploration of the solar system, George's legacy will live on."