Explore Worlds
Find Life
Defend Earth
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.
Mercury, Planet of Extremes
Mercury can teach us how planets form and what the early solar system was like when life arose on Earth.
Venus, Cloudy With A Chance of Life
Venus may have had oceans and been habitable to life before being transformed into an inhospitable wasteland.
Earth, Our Home Planet
Earth, the only planet known to support life, offers liquid water, an oxygen-rich atmosphere, and protection from the Sun’s harmful radiation.
The Moon, Preserving Earth's Origin Story
The Moon is the only world besides Earth ever visited by humans. By studying it, scientists can piece together Earth’s origin story.
Mars, the Red Planet
Mars once had liquid water on the surface and could have supported life. We don't know how it changed to the cold, dry desert-world it is today.
Asteroids, Comets, and Other Small Worlds
These leftover planet-building materials are time capsules that give us a peek into our origins.
Jupiter, the Planet with a Solar System of Its Own
Jupiter, our largest planet, teaches us how solar systems evolve. Its four planet-like moons make it a solar system of its own.
Saturn, Planet of Rings, Moons, and More to Explore
Saturn is the crown jewel of our solar system. It has a stunning set of rings, diverse moons, and so much more to explore.
Uranus, the Sideways Planet
Uranus may be the butt of all planet jokes, but there's much more to this world than potty humor.
Neptune, Planet of Wind and Ice
Neptune, our outermost planet, is a windy blue world with exotic ice, raging storms, rings, and a moon that could have a subsurface ocean.
Exoplanets, Worlds Orbiting Other Stars
We know of more than 4,000 planets orbiting other stars. Does one of them host life as we know it?
A Pale Blue Dot
Look again at that dot. That's here. That's home. That's us.
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 MoreLatest Articles
While We Weren't Watching: Apollo's Scientific Exploration of the Moon
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.
The Gift of Apollo
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?