While the internationally popular “Cosmos” series and late-night TV appearances with Johnny Carson helped make Carl Sagan a beloved public figure, some peers questioned the seriousness of such outreach. And as a member of NASA’s Voyager 1 mission, managers rejected his pleas for years before finally agreeing to point the distant spacecraft back toward Earth for a final photo, producing the iconic “Pale Blue Dot” image.

“They would say to him, ‘Carl, what’s the scientific virtue of seeing the Earth as a single dot?’” remembered Ann Druyan, Sagan’s widow and longtime collaborator. “But he never gave up, and ultimately, he succeeded in seeing the world how it really is: tiny, fragile. And it was Carl who could … make us look in wonder at ourselves and each other and realize how pathetic and how futile our conflicts are in the face of the vastness of space and time.”

Credit: Sreang Hok/Cornell University

Druyan, an Emmy and Peabody award-winning writer, producer and director, joined the Carl Sagan Institute (CSI) on Nov. 9 for a celebration of the late, legendary Cornell astronomy professor on what would have been his 90th birthday, honoring his passion for scientific inquiry, critical thinking and sharing the universe’s beauty and mystery.

In addition to tributes from loved ones and admirers, the four-hour program in Call Auditorium – part of the College of Arts and Sciences’ Arts Unplugged series, open to the public and streamed live to an audience of more than 2,000 – presented CSI researchers’ latest interdisciplinary research on the search for life beyond Earth that is advancing Sagan’s legacy, musical performances and, fittingly, a greeting from space.

“Carl Sagan inspired countless people worldwide as he shared the wonder of the cosmos, and I know he would appreciate the view that I have from this place,” NASA astronaut Don Pettit wrote from the International Space Station, where humans have lived continuously for 24 years. “He cared deeply about our planet and keenly questioned whether worlds circling other stars could harbor life.”

Dr. Joe Dervay ’80, a NASA flight surgeon, read Pettit’s message and recalled Sagan’s influence on campus and on his generation, as a teacher and “part of the fabric of our culture.” Other prominent well-wishers offering video tributes included “Science Guy” Bill Nye ’77; actor and science communicator Alan Alda; leaders of the nonprofit SETI (Search for Extraterrestrial Intelligence) Institute; and Sagan’s daughter, Sasha Sagan.

Cornell faculty members, graduate students and postdoctoral researchers – among CSI fellows spanning more than 15 departments – discussed ongoing efforts to detect life elsewhere in the solar system and on exoplanets. They include developing a database of biopigments and “light fingerprints” that could signal habitable worlds; using the James Webb Space Telescope to “sniff” exoplanet atmospheres; probing beneath Antarctic ice shelves to study both climate change and ocean worlds like Europa; re-creating lava worlds in the laboratory; and developing more sensitive spacecraft instruments.

Joshua Umansky-Castro, a doctoral candidate in aerospace engineering, discussed a project in Cornell Engineering’s Space Systems Design Studio to develop light sail technology that could be used for interstellar missions. Holograms mounted on the first spacecraft’s solar panels aim to inspire larger audiences, as Sagan did, to think about what messages could be sent to the stars. Buz Barstow, assistant professor of biological and environmental engineering in the College of Agriculture and Life Sciences (CALS), discussed research using synthetic biology to build sustainable energy technologies.

Credit: Sreang Hok/Cornell University

“There’s loads to play for here,” Barstow said. “We shouldn’t handicap ourselves by short-term thinking.”

Lisa Kaltenegger, CSI director and associate professor of astronomy (A&S), shared that more than 5,700 planets circling other stars have been identified to date and another 10,000 candidates are being vetted. The numbers suggest every second star has a planet and every fifth star has one that might support liquid water. With 200 billion stars in the Milky Way alone, that means “billions and billions” of possibilities for life, Kaltenegger said, echoing a famous Sagan phrase.

“This is incredibly hard, even with the biggest telescope,” said Kaltenegger, the author of “Alien Earths: The New Science of Planet Hunting in the Cosmos.” “But for the first time, the search has changed from impossible to possible.”

Contrasting Sagan, who died in 1996 at age 62, with other best-selling scientist authors of his era, Bruce Lewenstein, professor of communication (CALS) and of science and technology studies (A&S), noted that Sagan said he would be pleased if “Cosmos” viewers and readers did not remember facts but “found rekindled some of that ancient human joy in understanding the natural world, in the celebration of nature.”

Credit: Sreang Hok/Cornell University

“Sagan was absolutely committed to getting the science right,” Lewenstein said. “Nonetheless, imagination was central to Sagan’s vision.”

Between research presentations, Cornell Orchestra members performed the introduction to composer Charles Ives’ “The Unanswered Question.” A recording was played of “In the Words of Carl Sagan” by composer Joseph Turrin, who was in the audience.

Attendees also included Syracuse-area residents Paul Erickson ’09, his wife Jamie Erickson and their two young sons, the eldest named for Sagan. Paul said the astronomer’s teaching and outreach had had a profound impact at a challenging time in his youth, helping him to go from high school dropout to Cornell graduate, and later a Cornell lecturer.

“Reading his books and watching ‘Cosmos’ completely altered my entire life trajectory,” Erickson said.

Family activities preceding the event included an open house at the Spacecraft Planetary Image Facility and an appearance by the Ithaca Physics Bus. Later in the evening, Cornell Cinema hosted a screening of the 1997 movie “Contact,” developed by Sagan and Druyan, and the Cornell Astronomical Society welcomed stargazers at Fuertes Observatory.

The program closed with a recording of Sagan reading his “Pale Blue Dot” poem: “Look again at that dot,” it begins. “That’s here. That’s home. That’s us. On it, everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives … on a mote of dust, suspended in a sunbeam.”