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

We study the Sun to learn about how stars work, and to help protect our civilization from solar storms.

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, Earth's twin sister

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, gateway for science and exploration

The Moon is the only world besides Earth ever walked on by humans. By studying it, scientists can learn about Earth’s past and better understand worlds throughout the galaxy.

Mars, the red planet

Mars once had liquid water on the surface and could have supported life. Scientists are uncovering how it transformed into the cold, dry desert-world it is today.

Asteroids, comets, and other small worlds

Asteroids and comets are windows into the Solar System's past and a potential threat to Earth today.

Jupiter, the planet with a planetary system of its own

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

Io, Jupiter’s chaotic volcano moon

Io, one of Jupiter's four Galilean moons, is known for its explosivity.

Europa, Jupiter’s possible watery moon

Europa is the sixth-largest moon in the solar system and Jupiter’s fourth-largest satellite.

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.

Triton, Neptune's largest moon

Triton is likely a captured Kuiper Belt Object and possibly an ocean world.

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 beyond the Solar System

Some exoplanets could be habitable and are prime targets in the search for life beyond Earth.

A Pale Blue Dot

Look again at that dot. That's here. That's home. That's us.

Latest Articles

The Discovery of a Planet, Part 5: The Aftermath

The discovery of Planet X was announced to the world on March 13, 1930, which marked the anniversary of William Herschel’s discovery of Uranus in 1781 as well as Percival Lowell’s birthday. The observatory’s communiqué emphasized that the discovery was no coincidence, but the vindication of Lowell’s predictions made years before.

The Discovery of a Planet, Part 4: Clyde's Search

Since his teenage years Clyde Tombaugh had been an avid amateur astronomer and a gifted telescope builder. Based on instructions contained in an article from a boy’s Sunday school paper, he built a series of telescopes of increasing power and quality on the family farm.

Cassini's Radio Ear on Huygens

Scientists have released a new sound from Huygens, representing the radio signal that Cassini detected from the little probe as it descended to Titan's surface.

The Discovery of a Planet, Part 3: Planet X

The discovery of Neptune accounted for nearly all the unexplained motions of the outer planets of the Solar System. Nevertheless, several astronomers insisted that some unexplained residual motions remained, pointing to the presence of a ninth planet beyond the orbit of Neptune.

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