Orange sun with colorful planets trailing out to one side.

About the Planets

Our solar system has eight planets, and five dwarf planets - all located in an outer spiral arm of the Milky Way galaxy called the Orion Arm.




Dwarf Planets

The solar system has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. There are five officially recognized dwarf planets in our solar system: Ceres, Pluto, Haumea, Makemake, and Eris.

The inner, rocky planets are MercuryVenusEarth, and Mars. These worlds also are known as terrestrial planets because they have solid surfaces. Mercury, Earth, and Mars are currently being explored by spacecraft. Two rovers are on the surface of Mars. NASA's rover – Perseverance – landed on Mars on Feb. 18, 2021. Three missions are in development to return to Venus.

The outer planets are gas giants Jupiter and Saturn, and ice giants Uranus and Neptune. NASA's Juno spacecraft is on an extended mission at Jupiter, and ESA's JUICE mission is on the way to the Jovian system. NASA's Europa Clipper is launching in October 2024 to explore Jupiter's icy moon, Europa. The agency's Dragonfly rotorcraft lander will launch to Saturn's moon, Titan, no earlier than 2028.

Beyond Neptune, a newer class of smaller worlds called dwarf planets reign, including longtime favorite Pluto. NASA's New Horizons spacecraft visited Pluto in 2015, and is currently exploring the Kuiper Belt beyond Pluto. The other dwarf planets are Ceres, Makemake, Haumea, and Eris. Ceres, by the way, is the only dwarf planet in the inner solar system. It's located in the main asteroid belt between Mars and Jupiter.

Thousands more planets have been discovered beyond our solar system. Scientists call them exoplanets (exo means "from outside").

Planet Facts

  1. Mercury is gray with bright white patches, and craters visible in this image from the MESSENGER spacecraft.

    Mercury Facts

    The smallest planet in our solar system and nearest to the Sun, Mercury is only slightly larger than Earth's Moon. From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight would be as much as seven times brighter.

    Explore Mercury

  2. A serene-looking Venus with creamy white, and tan clouds.

    Venus Facts

    Venus is the second planet from the Sun, and Earth's closest planetary neighbor. It's the hottest planet in our solar system, and it is sometimes called Earth's twin.

    Explore Venus

  3. A view of Earth from Apollo 17 showing the blue ocean, reddish brown landmasses, and wispy, white clouds.

    Earth Facts

    Earth – our home planet – is the third planet from the Sun, and the fifth largest planet. It's the only place we know of inhabited by living things.

    Explore Earth

  4. Mars is a reddish brown in this image from a spacecraft. A deep gash is visible across the center of the planet.

    Mars Facts

    Mars – the fourth planet from the Sun – is a dusty, cold, desert world with a very thin atmosphere. This dynamic planet has seasons, polar ice caps, extinct volcanoes, canyons and weather.

    Explore Mars

  5. A view of Jupiter's Great Red Spot and colorful cloud bands of tan, brown, white, and orange as seen from the Juno spacecraft.

    Jupiter Facts

    Jupiter is the largest planet in our solar system – if it were a hollow shell, 1,000 Earths could fit inside. It's also the oldest planet, forming from the dust and gases left over from the Sun's formation 4.5 billion years ago.

    Explore Jupiter

  6. A spacecraft looks down on a soft gold-colored Saturn surrounded by its rings.

    Saturn Facts

    Saturn is the sixth planet from the Sun, and the second-largest planet in our solar system. Saturn is surrounded by a spectacular ring system, and it has dozens of moons.

    Explore Saturn

  7. Pale blue planet Uranus is seen against the darkness of space in an image from the Voyager 2 spacecraft.

    Uranus Facts

    Uranus is the seventh planet from the Sun, and it has the third largest diameter of planets in our solar system. Uranus appears to spin sideways.

    Explore Uranus

  8. Neptune is blue and banded with clouds and storms.

    Neptune Facts

    Neptune is the eighth and most distant planet in our solar system. Dark, cold, and whipped by supersonic winds, ice giant Neptune is more than 30 times as far from the Sun as Earth. 

    Explore Neptune

Dwarf Planet Facts

  1. Gray Ceres has a bright spot near its upper left side in this image from NASA's Dawn spacecraft.

    Ceres Facts

    Dwarf planet Ceres is the largest object in the asteroid belt between Mars and Jupiter, and it's the only dwarf planet located in the inner solar system. When NASA's Dawn arrived in 2015, Ceres became the first dwarf planet to receive a visit from a spacecraft.

    Explore Ceres

  2. Pluto is reddish and has a heart shape lighter patch in the lower right half of this image from the New Horizons spacecraft.

    Pluto Facts

    Pluto was long considered our solar system's ninth planet. But after the discovery of similar intriguing worlds deep in the Kuiper Belt, tiny Pluto was reclassified as a dwarf planet in 2006 by the International Astronomical Union.

    Explore Pluto

  3. Dwarf planet Haumea looks like a bright dot with two smaller ones on each side.

    Haumea Facts

    Haumea was nicknamed Santa by one discovery team. It's oval-shaped, and is one of the fastest rotating large objects in our solar system. The fast spin distorts Haumea's shape, making this dwarf planet look like a football.

    Explore Haumea

  4. 04

    Makemake Facts

    Makemake is slightly smaller than Pluto, and is the second-brightest object in the Kuiper Belt as seen from Earth while Pluto is the brightest. 

    Explore Makemake

  5. A gray planet with a distant moon, and a faraway Sun.

    Eris Facts

    The discovery of Eris help trigger a debate in the scientific community that led to the International Astronomical Union's decision in 2006 to clarify the definition of a planet. Pluto, Eris, and other similar objects are now classified as dwarf planets.

    Explore Eris

What is a Planet?

This seemingly simple question doesn't have a simple answer.

Read More
Illustration of eight planets and one dwarf planet displayed three across and three down.

Is There Another Planet in the Solar System?

It's an intriguing idea that might explains some current mysteries, but direct evidence of another planet has yet to be found.

Read more
A dark, bluish planet is shown orbiting far from the Sun in this artist's concept.
This illustration shows the distant view from Planet Nine back toward the Sun. The planet is thought to be gaseous, similar to Uranus and Neptune. Hypothetical lightning illuminates the night side.
Caltech/R. Hurt (IPAC)
Featured Story

Planet Sizes and Locations in Our Solar System

Our solar system has eight planets, and five officially recognized dwarf planets. Which planet is biggest? Which is smallest? What…

Read the Story
An illustration of colorful planets overlapping each other.