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.

Your Guide to Mercury

Mercury, the innermost planet, can teach us how the planets formed and what the early solar system was like when life arose on Earth.

Your Guide to Venus

Venus may have had oceans and been habitable to life before being transformed into an inhospitable wasteland.

Earth

Earth is our home and the only world known so far to harbor life.

Your Guide to the Moon

The Moon is the only world besides Earth ever visited by humans. By studying it, scientists can piece together Earth’s origin story.

Your Guide to Mars

Mars, the Red Planet, 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.

Your Guide to Asteroids, Comets, and Other Small Worlds

These leftover planet-building materials are like time capsules that give us a peek into our origins.

Your Guide to Jupiter

Jupiter, our largest planet, teaches us how solar systems evolve. Its four planet-like moons make it a solar system of its own.

Your Guide to Saturn

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

Uranus may be the butt of many jokes, but there's more to this ice giant than meets the eye.

Neptune

Chilly Neptune has winds that travel faster than the speed of sound on Earth.

Your Guide to Exoplanets

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.

Latest Articles

Haughton Impact Crater

Haughton Crater measures about 20 kilometers (12.4 miles) in diameter, and was formed 23 million years ago when either an asteroid or a comet collided with our planet.

Updates from Past Recipients of the Shoemaker NEO Grants (20 March 2001)

I just wanted to express my appreciation again to The Planetary Society for the Shoemaker Grant. Apogee Instruments delivered the AP6Ep purchased with the grant on 9 March 2001. Critical mass on all of the other components associated with implementing the proposal was reached last week.

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?

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