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, 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.
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
NASA’s Lucy mission: an odyssey to the Trojan asteroids
On October 16, NASA's Lucy spacecraft is expected to depart for the Trojan asteroids — rocky bodies that share an orbit with Jupiter.
The shape of Jupiter’s Great Red Spot is changing. Here’s why.
A new study says the winds within the famous Great Red Spot are speeding up in some places and slowing down in others.
Planetary protection: How to explore Mars and other worlds responsibly
Planetary protection means protecting other worlds from Earthly microbes and containing possible microbes that sample return missions might bring back to Earth.
What are the most Earth-like worlds we’ve found?
The ongoing hunt for Earth-like worlds, especially over the next few decades, hopes to illuminate how ordinary and extraordinary our planet may be.