Co-founded by Carl Sagan in 1980, The Planetary Society is a member-funded nonprofit organization dedicated to advancing space science and exploration through three core …

They established The Planetary Society to give anyone from anywhere in the world an active role in advancing space exploration. Today, The Planetary Society continues this work, under the …

What’s up in the night sky: December 2025 Our monthly feature focuses on easy and fun things to see in the night sky, including eclipses, supermoons, meteor showers, planetary conjunctions, …

We connect with planetary exploration experts from around the world to strengthen our work and support international exploration efforts. Our 50,000+ international membership makes us the …

The latest stories from The Planetary Society, featuring humanity's quest to explore worlds, find life, and defend Earth.

Together with our members and supporters, we’re on a mission to explore worlds, find life off Earth, and protect our planet from dangerous asteroids. Join us at planetary.org.

What is a Planet? It's right there in our name: The Planetary Society. But what is a planet? This seemingly simple question is the subject of much debate. Learn More

For over 4 decades, our members have made strides in advancing planetary exploration, planetary defense, and the search for life beyond Earth. We have delivered tens of thousands …

Jan 30, 2025 · From funding early Mars rover testing to naming planetary bodies and developing sample return technologies, Planetary Society members have funded contributions to more …

To figure out where that boundary lies, and how geoscientists might classify planets, it helps to know what planetary scientists have learned about the variety of worlds in our solar system, …