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.
The Sun, our solar system’s star
Our Sun is an active star, frequently bursting out storms of plasma and radiation into the solar system.
Mercury, world 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
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.
Enceladus, Saturn’s moon with a hidden ocean
With its subsurface ocean and so-called "tiger stripes," Enceladus is one of Saturn's most fascinating moons.
Titan, a moon with familiar vistas
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.
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.
Pluto, the Kuiper Belt’s most famous dwarf planet
Pluto is a dwarf planet and the largest of the Kuiper Belt objects (KBOs) — a collection of ice-rock bodies found outside Neptune’s orbit.
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
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Spirit 'phoned home' this morning and returned some good engineering data, but the Mars rover remains in
Spirit Suffers "Serious Anomaly," But Continues 'Beeping' Home
Something is wrong with Spirit, but what exactly it is -- and just how serious it is -- the Mars Exploration Rover team isn't sure.
Titan: Arizona in an Icebox?
A week after Huygens' descent, the emerging picture of the surface of that smoggy world is of an arid, icy desert, where periodic storms of methane rain create transient rivers that wash sooty soil from icy highlands out to short-lived pools and lakes. The pools dry up -- perhaps sinking into a sandy soil of glass-like water ice -- and the Titanian desert waits for another methane storm.
Spirit Discovers Surprises in Martian Soil, but Earth Weather Blocks Commands to Continue Work
Spirit got off to a running start this week, using three of the four instruments on her robotic arm to study a patch of Martian soil, and the football-sized rock Adirondack.