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Planets Facts

south pole

You live in or on many places, including on a planet. We live on planet Earth but there are 8 other planets that are all a part of the solar system. These planets have a special relationship because they all revolve around the SUN.

solar system

More About the Solar System

Our solar systems has:

  • One central star called the SUN
  • Eight planets:
    • Mercury (closest to the sun)
    • Venus
    • Earth
    • Mars
    • Jupiter
    • Saturn
    • Uranus
    • Neptune (farthest from the sun)
  • More than 60 moons
  • Millions of rocky asteroids
  • Billions of icy comets
  • Four dwarf planets:
    • Pluto
    • Ceres
    • Makemake
    • Eris

How old is the solar system?

About 4.5 billion years old.

How was it formed?

All of the solar system except the sun are loose particles left over from the formation of the Sun. Find out more....Q and A

How big is the solar system?

The Oort Cloud, a collection of comets orbiting the solar system, is considered the boundary of our solar system. It lies about 50,000 astronomical units (or almost one light-year) away from the sun.

Are all the planets the same?

They are all different colors and sizes. Some are rocky, some are made of gas, some have rings, some have moons, one is almost all ice. Follow this link for more...

Do the planets have the same shaped orbit?

No! All the planets have their own unique path around the sun.

Can you see the planets?

You can see Mercury, Venus, Mars, Jupiter and Saturn without a telescope but not Uranus or Neptune.

Where do the planet names come from?

Every planet, except for Earth, was named for an ancient Roman god or goddess.

Wasn't Pluto once called a planet?

Yes, but scientists recently reclassified it as a dwarf planet. Read here for more.

Planetary orbitsWhat Is An Orbit?

An orbit is the path followed by an object in space as it moves moves around another object. Read more, and find out about Sir Issac Newton.

Earth takes 365 days to go around the sun, while Pluto takes 248 years.

The Rocky Planets
Mercury, Venus, Earth, and Mars

Rocky planets

The Rocky Planets are small and similar in composition to Earth. They do not have rings. Earth and Mars have moons.

The Gaseous Planets, (or Gas Giants)
Jupiter, Saturn, Uranus, and Neptune

The Gas Giants, larger than the rocky planets, have rings and moons. They are made mostly of hydrogen, helium, frozen water, ammonia, methane and carbon monoxide.

Saturn

Jupiter and Saturn contain the largest percentages of hydrogen and helium. Uranus and Neptune contain largest shares of ices - frozen water, ammonia, methane, and carbon monoxide.

The Ice Dwarf Planet
Pluto

Pluto

The frozen part of Pluto is made of nitrogen.

Let's Look at the Planets

Mercury has almost no atmosphere and can be very, very hot and very, very cold.

MercuryThe Messenger space probe will orbit Mercury in 2011 to let us learn more about the closest planet to the sun.

Click here for a different view of Mercury.

Mercury symbol

Investigate more about Mercury.

Venus is the hottest planet and the brightest object in the sky after the Sun and the Moon.

VenusThe Soviet space program landed 10 probes on Venus. Pictures taken by these landers can be seen here.

Click here for a different view of Venus.

Venus symbol

Investigate more about Venus.

Earth

Earth is the only planet with liquid water and the only planet that has life!

Earth has one moon but Jupiter has 60!!!

We use spacecraft to learn about Earth in much the same way we explore other planets.

Click on the image for a larger size view.

Earth symbol

Investigate more about Earth.

Mars

Mars has enormous volcanoes, valleys and dust storms. Olympus Mons might be the largest volcano in the Solar System.

We've been sending spacecraft to Mars since 1960.

Here's the latest information from Mars.

Click here for a different view of Mars.

Mars symbol

Investigate more about Mars.

Jupiter

Jupiter is so big that all the other planets in the Solar System could fit inside. It has a thick atmosphere, visible bands, and a great red spot, which is a storm.

In 1610, when Galileo first pointed a telescope at the sky, he discovered Jupiter's four moons: Io, Europa, Ganymede, and Callisto.

Click on the image for a full size.

Jupiter symbol

Investigate more about Jupiter.

Saturn

Saturn has the most spectacular and complex set of rings in the solar system. The rings are made of chunks of ice and rock, are very thin sheets, and there are lots of them!

Follow the Cassini-Huygens Mission to Saturn.

Click on the image for a larger view.

Saturn symbol

Investigate more about Saturn.

Uranus

Uranus rotates on its side. Because of this daytime on Uranus lasts a whole summer and the seasons are very different from ours.

The Voyager Two spacecraft provided us with our best information about Uranus to date.

Click on the image for a larger view.

Uranus symbol

Investigate more about Uranus.

Neptune

Neptune

Each season on Neptune lasts 40 years. Its blue color is caused by methane in its atmosphere.

Neptune has a dark spots which are anti-cyclones in the planet's freezing clouds.

Click on the image for a larger view.

Neptune symbol

Investigate more about Neptune.

Past Neptune

Past Neptune there are a class of objects known as the trans-Neptunians. The most well-known of these is the dwarf planet, Pluto. But there are at least two more dwarf planets, Eris and Makemake, and a possible third, Sedna. This chart will show some of the objects we know about.

Pluto

Pluto is so small that some Solar System moons are bigger than Pluto. Pluto is usually the farther away from the sun than Neptune, but its unique orbit sometimes brings it closer than the eighth planet. Pluto's surface is covered by ice made from frozen Nitrogen.

It has three moons, Charon, Nix, and Hydra.

In July, 2015, the New Horizons spacecraft will visit Pluto.

Pluto was changed from a planet to a dwarf planet on August 24, 2006.

Pluto symbol

Investigate more about Pluto.

Kuiper Belt & Beyond

Pluto is just one of the many thousands of objects that make up the Kuiper Belt. These are the icy remnants of the solar system's formation 4.5 billion years ago.

Astronomers believe that past the Kuiper Belt is the Oort Cloud, a ball of comets that surrounds the solar system at almost a light-year away. This marks the edge of our solar system.

Take off to "Windows on the Universe" where you'll find planet information about size, mass and gravity, length of day and year, orbit, moons, rings, temperature and more...in Spanish and English.

Mercury Jupiter
Venus Saturn
Earth Uranus
Mars Neptune
Pluto

NASA FACT

"When the Cassini-Huygens spacecraft arrived at Saturn on July 4, 2004 it was traveling so fast that engineers had to burn the spacecraft's engines for 97 minutes to slow it down. If mission engineers didn't do this, the spacecraft would keep on going, instead of entering the orbit around Saturn."

Read more NASA facts here.

Man has always been fascinated by space but we only began to explore in 1957. Here is a Chronology of Lunar and Planetary Exploration

Astronaut

Think like a scientist…. how would you go about finding water on Mars?

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