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 enterprises.

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

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 largest, …

This print by artist and Planetary Society supporter Anna Moore, titled “Orbit,” shows a repeating pattern of spacecraft around our planet. “Orbit” captures the role of technology in space science and …

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 of petitions to …

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

What’s up in the night sky: January 2026 Our monthly feature focuses on easy and fun things to see in the night sky, including eclipses, supermoons, meteor showers, planetary conjunctions, and 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, and which …

Jan 3, 2026 · Our monthly feature focuses on easy and fun things to see in the night sky, including eclipses, supermoons, meteor showers, planetary conjunctions, and…

Oct 11, 2022 · For planetary scientists, JWST’s greatest strength is its incredible spatial resolution combined with its ability to capture images using infrared spectroscopy.