Where did we come from? Are we alone in the Universe? We can only answer these questions by exploring the planets and other worlds of our solar system and beyond. Learn why these worlds are so important, and how you can get involved.
Saturn's largest moon, Titan, is both the only other place in the solar system with liquid on its surface and the only moon with a thick atmosphere, making it a tantalizing destination to search for life.
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
Apollo gave us our money's worth. The Apollo lunar samples, totaling 381 kilograms (838 pounds), along with thousands of photographs and other data, are still yielding clues to the world that has been our Rosetta stone for deciphering planetary evolution.
Carl Sagan writes that once upon a time, we soared into the solar system. For a few years. Then we hurried back. Why? What happened? What was Apollo really about?