Carl Sagan Day

Carl Sagan Day is observed on November 9, the birthday of astronomer and science communicator Carl Sagan. It honors his work in astronomy and his gift for making big questions about the universe understandable to people of all ages.

How Carl Sagan Day started

According to the NASA Exoplanet Science Institute, November 9 was celebrated in many places as Sagan Day for the first time in 2009. The date marks Sagan’s birthday. Groups observe the day in different ways, often reflecting on his scientific work and public outreach.

Sagan’s influence can also be seen in NASA’s Sagan Program, started in 2008 to inspire and support the next generation of exoplanet researchers. The program includes postdoctoral fellowships and summer workshops. Astronomers who received these fellowships have described how Sagan’s work helped spark their interest in science and in questions about planets and life beyond Earth.

Sagan’s influence on science and culture

Many people know Sagan through the television series Cosmos: A Personal Voyage. His scientific and public outreach work helped make science more accessible and showed a generation that becoming a scientist was something people from any background could aspire to.

Sagan also wrote books for general readers, including Cosmos. Fellow astronomers have recalled that the book inspired them to become scientists. His approach paired openness to new ideas with careful skepticism, encouraging people to ask bold questions while scrutinizing the evidence.

Sagan’s work helped make the question of life elsewhere in the universe relevant to the scientific community. Astronomers have since explored the diversity, formation, and evolution of planets beyond our Solar System. This research continues the kind of curiosity about other worlds that Sagan encouraged.

Carl Sagan Day is a chance to revisit his work and follow a question of your own. You might start with a book, a science program, or a conversation about what we know—and how we know it.

Ways to observe Carl Sagan Day

• Read a passage from one of Sagan’s books, such as Cosmos. Notice how he invites readers to think about the universe and our place in it.
• Visit a planetarium, science museum, or public observatory. Check its schedule first; some venues hold special programs, while others offer regular exhibits and viewing sessions.
• Take a short stargazing break. Find a safe spot with a clear view of the sky, use a star chart or astronomy app to identify a few objects, and remember that what you can see depends on your location and the weather.
• Talk with children about the possibility of life beyond Earth. What would you want to know about other worlds, and what evidence could help answer those questions?
• Share a science book, documentary, or astronomy activity with a friend or family member. Keep the focus on questions: What do we know, how do we know it, and what would we like to learn next?

Reviewed by the Holiday List editorial team on November 4, 2026 · Last updated November 4, 2026.

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