Carl Sagan Would Turn 92 as Voyager 1 Nears One Light-Day From Earth

Nov. 9 would have been the 92nd birthday of Carl Sagan, the astronomer who became one of the best-known science popularizers through his books and the 1980 television series "Cosmos," according to EarthSky. The anniversary comes as Voyager 1, one of the spacecraft that carries a message Sagan helped design, is expected to reach a distance of 1 light-day from Earth on Nov. 18, 2026.

EarthSky describes Sagan as a researcher who also shaped the U.S. space program, and says the messages he placed aboard spacecraft leaving the solar system may be his greatest legacy.

Key steps in Sagan's career

• Nov. 9, 1934: Carl Edward Sagan is born in Brooklyn, New York. He later studies physics at the University of Chicago.
• 1960: He earns his doctorate in astronomy and astrophysics.
• 1960s: Early research examines the atmospheres of Mars and Venus. Scientists were trying to understand why Mars is so cold and Venus so hot. Sagan argued that Venus could be a greenhouse furnace, using data from steam boiler engineering tables.
• 1966: He helps Soviet astronomer I. S. Shklovskii revise and expand the book Intelligent Life in the Universe.
• 1968: Harvard University denies him tenure. Some speculated the reason was his controversial views on extraterrestrial intelligence. He then joins Cornell University in Ithaca, New York, where he stays for the rest of his career.
• 1972 and 1973: Pioneer 10 and Pioneer 11 launch carrying plaques that Sagan helped design.
• 1977: The Voyager probes launch with Golden Records he helped shape.
• 1980s: He promotes nuclear disarmament and is one of the five authors of the nuclear winter concept.
• Dec. 20, 1996: He dies of pneumonia at age 62.

The messages he sent toward the stars

EarthSky reports that the idea for the Pioneer plaques came from Eric Burgess, a journalist and consultant. He approached Sagan, NASA agreed, and the agency gave Sagan three weeks to prepare a message. Sagan designed the gold-anodized aluminum plaques with astronomer Frank Drake, creator of the Drake Equation. Linda Salzman Sagan, his wife at the time, prepared the artwork. Both Pioneer craft are now billions of miles from Earth and coasting toward interstellar space.

Sagan and Ann Druyan, then his wife-to-be, contributed to the Voyager Golden Records. Each record holds 116 images showing scientific works and people in everyday activities. It also includes music by artists such as Bach, Mozart and Chuck Berry, an hour-long recording of Druyan's brainwaves, and greetings in 55 languages.

EarthSky also notes that Sagan helped brief astronauts before their trip to the moon. He took part in the Mariner, Viking, Galileo and Voyager missions and worked on choosing landing sites for the two Viking probes sent to Mars in the 1970s.

Why it matters: science for a wide audience

By EarthSky's account, Sagan published more than 600 scientific papers and articles and wrote, co-wrote or edited more than 20 books. The outlet says his outreach encouraged science literacy among Americans and around the world, and that he continues to inspire young scientists and science communicators.

EarthSky also credits his nuclear winter work with showing that no one would win a nuclear war. It says the work is hard to measure in its influence on global thinking at the time, and adds that the Cold War ended not long afterward. The outlet presents that timing as a possible link, not an established cause.

Among the lines EarthSky highlights is his observation that the elements in our bodies were made inside collapsing stars, and that "We are made of starstuff."

What's next for Voyager 1

EarthSky says the Voyager probes launched later than the Pioneers but travel faster. Voyager 1 and Voyager 2 have both reached interstellar space. Voyager 1 is the farthest human-made object from Earth, and it is expected to reach 1 light-day from Earth on Nov. 18, 2026. Voyager 2 is closer than Voyager 1 but farther out than Pioneer 10.

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Around Prague, based on reporting by EarthSky