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 …

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 …

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

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 …

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 bring planetary defense experts together from around the world to work on advancing solutions to the asteroid threat. We co-sponsor, attend, and organize activities at academic …

Dec 4, 2025 · The Planetary Science Caucus, now in its second year, is officially reorganized and has hit the ground running; organizing against the devastating proposed cuts and rallying …

Explore the membership options of The Planetary Society and join fellow space enthusiasts in advancing space science and exploration.

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.

Apr 21, 2020 · 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 …