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The Planet Mercury: Astronomy and Space for Kids - FreeSchool

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The Planet Venus: Astronomy and Space for Kids - FreeSchool

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Was There Water on Mars?  | Let's Explore Mars! | SciShow Kids

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The Nine Planets is an encyclopedic overview with facts and information about mythology and current scientific knowledge of the planets, moons, and other objects in our solar system and beyond.

The 9 Planets in Our Solar System

The Five Dwarf Planets

Other Objects in The Solar System

Earth Science course

Excel High School has an online high school Earth Science course. Learn more about the course details here.

Northgate Academy offers Earth science and astronomy as online homeschooling courses.

Washington Technical Institute is an accredited college that offers online paralegal program and more.

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The Nine Planets of The Solar System | Eight Planets Without Pluto

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An overview of the history, mythology and current scientific knowledge of the planets, moons and other objects in our solar system.

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The Planet Earth: Astronomy and Space for Kids - FreeSchool

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All About the Sun for Kids: Astronomy and Space for Children

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All About Jupiter for Children: Astronomy and Space for Kids - FreeSchool

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Earth is far from the only celestial body in the Solar System.

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All About Saturn for Children: Astronomy and Space for Kids - FreeSchool

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The Nine Planets is an encyclopedic overview with facts and information about mythology and current scientific knowledge of the planets, moons, and other objects in our solar system and beyond.

The 9 Planets in Our Solar System

The Five Dwarf Planets

Other Objects in The Solar System

Earth Science course

Excel High School has an online high school Earth Science course. Learn more about the course details here.

Northgate Academy offers Earth science and astronomy as online homeschooling courses.

Washington Technical Institute is an accredited college that offers online paralegal program and more.

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The Nine Planets of The Solar System | Eight Planets Without Pluto

# data[].attributes.attachment_link.description
An overview of the history, mythology and current scientific knowledge of the planets, moons and other objects in our solar system.

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Earth is far from the only celestial body in the Solar System.

# data[].attributes.attachment_link.description
Earth is far from the only celestial body in the Solar System.

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Earth is far from the only celestial body in the Solar System.

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Earth is far from the only celestial body in the Solar System.

# data[].attributes.attachment_link.description
Earth is far from the only celestial body in the Solar System.

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Earth is far from the only celestial body in the Solar System.

# data[].attributes.attachment_link.description
Earth is far from the only celestial body in the Solar System.

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The Nine Planets is an encyclopedic overview with facts and information about mythology and current scientific knowledge of the planets, moons, and other objects in our solar system and beyond.

The 9 Planets in Our Solar System

The Five Dwarf Planets

Other Objects in The Solar System

Earth Science course

Excel High School has an online high school Earth Science course. Learn more about the course details here.

Northgate Academy offers Earth science and astronomy as online homeschooling courses.

Washington Technical Institute is an accredited college that offers online paralegal program and more.

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The Nine Planets of The Solar System | Eight Planets Without Pluto

# data[].attributes.attachment_link.description
An overview of the history, mythology and current scientific knowledge of the planets, moons and other objects in our solar system.

# data[].attributes.attachment_link.readable_text
The Nine Planets is an encyclopedic overview with facts and information about mythology and current scientific knowledge of the planets, moons, and other objects in our solar system and beyond.

The 9 Planets in Our Solar System

The Five Dwarf Planets

Other Objects in The Solar System

Earth Science course

Excel High School has an online high school Earth Science course. Learn more about the course details here.

Northgate Academy offers Earth science and astronomy as online homeschooling courses.

Washington Technical Institute is an accredited college that offers online paralegal program and more.

# data[].attributes.attachment_link.title
The Nine Planets of The Solar System | Eight Planets Without Pluto

# data[].attributes.attachment_link.description
An overview of the history, mythology and current scientific knowledge of the planets, moons and other objects in our solar system.

# data[].attributes.attachment_link.readable_text
The Nine Planets is an encyclopedic overview with facts and information about mythology and current scientific knowledge of the planets, moons, and other objects in our solar system and beyond.

The 9 Planets in Our Solar System

The Five Dwarf Planets

Other Objects in The Solar System

Earth Science course

Excel High School has an online high school Earth Science course. Learn more about the course details here.

Northgate Academy offers Earth science and astronomy as online homeschooling courses.

Washington Technical Institute is an accredited college that offers online paralegal program and more.

# data[].attributes.attachment_link.title
The Nine Planets of The Solar System | Eight Planets Without Pluto

# data[].attributes.attachment_link.description
An overview of the history, mythology and current scientific knowledge of the planets, moons and other objects in our solar system.

# data[].attributes.attachment_link.readable_text
The Nine Planets is an encyclopedic overview with facts and information about mythology and current scientific knowledge of the planets, moons, and other objects in our solar system and beyond.

The 9 Planets in Our Solar System

The Five Dwarf Planets

Other Objects in The Solar System

Earth Science course

Excel High School has an online high school Earth Science course. Learn more about the course details here.

Northgate Academy offers Earth science and astronomy as online homeschooling courses.

Washington Technical Institute is an accredited college that offers online paralegal program and more.

# data[].attributes.attachment_link.title
The Nine Planets of The Solar System | Eight Planets Without Pluto

# data[].attributes.attachment_link.description
An overview of the history, mythology and current scientific knowledge of the planets, moons and other objects in our solar system.

# data[].attributes.attachment_link.readable_text
The Nine Planets is an encyclopedic overview with facts and information about mythology and current scientific knowledge of the planets, moons, and other objects in our solar system and beyond.

The 9 Planets in Our Solar System

The Five Dwarf Planets

Other Objects in The Solar System

Earth Science course

Excel High School has an online high school Earth Science course. Learn more about the course details here.

Northgate Academy offers Earth science and astronomy as online homeschooling courses.

Washington Technical Institute is an accredited college that offers online paralegal program and more.

# data[].attributes.attachment_link.title
The Nine Planets of The Solar System | Eight Planets Without Pluto

# data[].attributes.attachment_link.description
An overview of the history, mythology and current scientific knowledge of the planets, moons and other objects in our solar system.

# data[].attributes.attachment_link.readable_text
The Nine Planets is an encyclopedic overview with facts and information about mythology and current scientific knowledge of the planets, moons, and other objects in our solar system and beyond.

The 9 Planets in Our Solar System

The Five Dwarf Planets

Other Objects in The Solar System

Earth Science course

Excel High School has an online high school Earth Science course. Learn more about the course details here.

Northgate Academy offers Earth science and astronomy as online homeschooling courses.

Washington Technical Institute is an accredited college that offers online paralegal program and more.

# data[].attributes.attachment_link.title
The Nine Planets of The Solar System | Eight Planets Without Pluto

# data[].attributes.attachment_link.description
An overview of the history, mythology and current scientific knowledge of the planets, moons and other objects in our solar system.

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Explore Saturn's Rings | Astronomy for Kids

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All About Uranus for Kids: Astronomy and Space for Children - FreeSchool

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All About Neptune for Kids: Astronomy and Space for Children - FreeSchool

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All About Comets for Kids: Astronomy and Space for Children - FreeSchool

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All About Stars for Kids: Astronomy and Space for Children - FreeSchool

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What Is an Asteroid? | Asteroids for kids | Learn all about asteroids

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Where do comets come from?

Comets are mostly found way out in the solar system. Some exist in a wide disk beyond the orbit of Neptune called the Kuiper Belt. We call these short-period comets. They take less than 200 years to orbit the Sun.

Other comets live in the Oort Cloud, the sphere-shaped, outer edge of the solar system that is about 50 times farther away from the Sun than the Kuiper Belt. These are called long-period comets because they take much longer to orbit the Sun. The comet with the longest known orbit takes more than 250,000 years to make just one trip around the Sun!

What brings comets near Earth so we can see them?

The gravity of a planet or star can pull comets from their homes in the Kuiper Belt or Oort Cloud. This tug can redirect a comet toward the Sun. The paths of these redirected comets look like long, stretched ovals.

As the comet is pulled faster and faster toward the Sun, it swings around behind the Sun, then heads back toward where it came from. Some comets dive right into the Sun, never to be seen again. When the comet is in the inner solar system, either coming or going, that's when we may see it in our skies.

What are the parts of a comet?

At the heart of every comet is a solid, frozen core called the nucleus. This ball of dust and ice is usually less than 10 miles (16 kilometers) across - about the size of a small town. When comets are out in the Kuiper Belt or Oort Cloud, scientists believe that's pretty much all there is to them - just frozen nuclei.

But when a comet gets close to the Sun, it starts heating up. Eventually, the ice begins to turn to gas. This can also cause jets of gas to burst out of the comet, bringing dust with it. The gas and dust create a huge, fuzzy cloud around the nucleus called the coma.

Why do comets have tails?

As dust and gases stream away from the nucleus, sunlight and particles coming from the Sun push them into a bright tail that stretches behind the comet for millions of miles.

When astronomers look closely, they find that comets actually have two separate tails. One looks white and is made of dust. This dust tail traces a broad, gently curving path behind the comet. The other tail is bluish and is made up of electrically charged gas molecules, or ions. The ion tail always points directly away from the Sun.

How do we learn about comets?

People have been interested in comets for thousands of years. But it wasn't possible to get a good view of a comet nucleus from Earth since it is shrouded by the gas and dust of the coma. In recent years, though, several spacecraft have had the chance to study comets up close.

NASA's Stardust mission collected samples from Comet Wild 2 (prounounced like "Vilt two") and brought them back to Earth. Scientists found those particles to be rich in hydrocarbons, which are chemicals we consider the "building blocks" of life.

Rosetta, a mission of the European Space Agency that had several NASA instruments onboard, studied Comet 67P Churyumov-Gerasimenko. Rosetta dropped a lander on the nucleus, then orbited the comet for two years. Rosetta detected building blocks of life on this comet, too. And images showed Comet 67P to be a rugged object with lots of activity shaping its surface.

Thanks to these missions and others like them, we now know a lot more about the structure of comets and the types of chemicals found on and around them. We've even learned a bit more about the formation of our solar system!

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Neptune is dark, cold, and very windy. It's the last of the planets in our solar system. It's more than 30 times as far from the sun as Earth is. Neptune is very similar to Uranus. It's made of a thick fog of water, ammonia, and methane over an Earth-sized solid center. Its atmosphere is made of hydrogen, helium, and methane. The methane gives Neptune the same blue color as Uranus. Neptune has six rings, but they're very hard to see.

Structure and Surface

Neptune is encircled by six rings.

Neptune, like Uranus, is an ice giant. It's similar to a gas giant. It is made of a thick soup of water, ammonia, and methane flowing over a solid core about the size of Earth.

Neptune has a thick, windy atmosphere.

Time on Neptune

One day on Neptune goes by in 16 hours.

Neptune has such a long journey around the Sun it takes 165 Earth years to go around once. That's a long year!

Neptune's Neighbors

Neptune has 14 moons.

Neptune is the eighth and most distant planet from the Sun. That means Uranus is Neptune's only neighboring planet.

Quick History

Neptune was discovered in 1846 by Urbain Le Verrier, John Couch Adams, and Johann Galle.

Only Voyager 2 has visited Neptune.

What does Neptune look like?

For more information visit:
NASA Solar System Exploration

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Jupiter is the biggest planet in our solar system. It's similar to a star, but it never got massive enough to start burning. It is covered in swirling cloud stripes. It has big storms like the Great Red Spot, which has been going for hundreds of years. Jupiter is a gas giant and doesn't have a solid surface, but it may have a solid inner core about the size of Earth. Jupiter also has rings, but they're too faint to see very well.

Structure and Surface

Jupiter is the biggest planet in our solar system.

Jupiter is a gas giant. It is made mostly of hydrogen and helium.

Jupiter has a very thick atmosphere.

Jupiter has rings, but they're very hard to see.

Time on Jupiter

One day on Jupiter goes by in just 10 hours.

One year on Jupiter is the same as 11.8 Earth years.

Jupiter's Neighbors

Jupiter has 80 confirmed moons.

Jupiter is the fifth planet from the Sun. That means Mars and Saturn are Jupiter's neighboring planets.

Quick History

Jupiter has been known since ancient times because it can be seen without advanced telescopes.

Jupiter has been visited or passed by several spacecraft, orbiters and probes, such as Pioneer 10 and 11, Voyager 1 and 2, Cassini, New Horizons, and Juno.

What does Jupiter look like?

For more information visit:
NASA Solar System Exploration

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Uranus is made of water, methane, and ammonia fluids above a small rocky center. Its atmosphere is made of hydrogen and helium like Jupiter and Saturn, but it also has methane. The methane makes Uranus blue.

Uranus also has faint rings. The inner rings are narrow and dark. The outer rings are brightly colored and easier to see. Like Venus, Uranus rotates in the opposite direction as most other planets. And unlike any other planet, Uranus rotates on its side.

Structure and Surface

Uranus is surrounded by a set of 13 rings.

Uranus is an ice giant (instead of a gas giant). It is mostly made of flowing icy materials above a solid core.

Uranus has a thick atmosphere made of methane, hydrogen, and helium.

Uranus is the only planet that spins on its side.

Uranus spins the opposite direction as Earth and most other planets.

Time on Uranus

One day on Uranus lasts a little over 17 hours (17 hours and 14 minutes, to be exact).

One year on Uranus is the same as 84 years on Earth. That's a long time to wait for a birthday cake.

Uranus' Neighbors

Uranus has 27 known moons.

Uranus is the seventh planet from the Sun. That means Saturn and Neptune are Uranus' neighboring planets.

Quick History

Uranus was discovered in 1781 by William Herschel in Great Britain.

Uranus has only been visited by Voyager 2.

What does Uranus look like?

For more information visit:
NASA Solar System Exploration

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All About Mars | NASA Space Place – NASA Science for Kids

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Even though Venus isn't the closest planet to the Sun, it is still the hottest. It has a thick atmosphere full of the greenhouse gas carbon dioxide and clouds made of sulfuric acid. The gas traps heat and keeps Venus toasty warm. In fact, it's so hot on Venus, metals like lead would be puddles of melted liquid.

Venus looks like a very active planet. It has mountains and volcanoes. Venus is similar in size to Earth. Earth is just a little bit bigger.

Venus is unusual because it spins the opposite direction of Earth and most other planets. And its rotation is very slow. It takes about 243 Earth days to spin around just once. Because it's so close to the Sun, a year goes by fast. It takes 225 Earth days for Venus to go all the way around the Sun. That means that a day on Venus is a little longer than a year on Venus.

Since the day and year lengths are similar, one day on Venus is not like a day on Earth. Here, the Sun rises and sets once each day. But on Venus, the Sun rises every 117 Earth days. That means the Sun rises two times during each year on Venus, even though it is still the same day on Venus! And because Venus rotates backwards, the Sun rises in the west and sets in the east.

Just like Mercury, Venus doesn't have any moons.

Structure and Surface

Venus is the hottest planet in our solar system.

Venus is a terrestrial planet. It is small and rocky.

Venus has a thick atmosphere. It traps heat and makes Venus very hot.

Venus has an active surface, including volcanoes!

Venus spins the opposite direction of Earth and most other planets.

Time on Venus

A day on Venus lasts 243 Earth days.

A year on Venus lasts 225 Earth days.

Venus's Neighbors

Venus does not have any moons.

Venus is the second planet from the Sun. That means Mercury and Earth are Venus's neighboring planets.

Quick History

Venus has been known since ancient times because it can be seen easily without a telescope.

Venus has been visited by several spacecraft: Mariner 2, Mariner 5, Mariner 10, Pioneer Venus 1, Pioneer Venus 2, and an orbiter called Magellan.

What does Venus look like?

For more information visit:
NASA Solar System Exploration

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Scientists have ideas about why Saturn has rings, but no one knows for sure.

Are they solid like the CD you used to make your model? Or are they made of many particles dancing in formation around the planet? Four robotic spacecraft from Earth have visited Saturn-Pioneer 11, Voyager 1, Voyager 2 and Cassini. They have revealed many surprising things about Saturn's rings.

The rings are about 400,000 kilometers (240,000 miles) wide. That's the distance from the Earth to the Moon! But the rings are as little as 100 meters (330 feet) thick. They range from particles too tiny to see to "particles" the size of a bus. Scientists think they are icy snowballs or ice covered rocks.

There are actually many rings-maybe 500 to 1000. There are also gaps in the rings.

The Cassini spacecraft arrived at Saturn in July 2004. It orbited Saturn for 13 years, studying Saturn, its rings, and its moons much more thoroughly than the earlier spacecraft could.

Cassini also carried a probe, called Huygens (HOY-guns), that parachuted into the atmosphere of Saturn's giant moon Titan. Huygens sent back amazing information and images from this strange world whose surface we have never seen.

Cassini and Huygens made many exciting discoveries. In September 2017, Cassini ended its mission with a planned plunge into Saturn's atmosphere.

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Scientists have ideas about why Saturn has rings, but no one knows for sure. Are they solid like the CD you used to make your model ? Or are they made of many particles dancing in formation around the planet? Four robotic spacecraft from Earth have visited Saturn-Pioneer 11, Voyager 1, Voyager 2 and Cassini.

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Asteroids are small, rocky objects that orbit the sun. Although asteroids orbit the sun like planets, they are much smaller than planets.

There are lots of asteroids in our solar system. Most of them live in the main asteroid belt -a region between the orbits of Mars and Jupiter.

Asteroids hang out in other places, too. For example, some asteroids are found in the orbital path of planets. This means that the asteroid and the planet follow the same path around the sun. Earth and a few other planets have asteroids like this.

Where did asteroids come from?

Asteroids are left over from the formation of our solar system. Our solar system began about 4.6 billion years ago when a big cloud of gas and dust collapsed. When this happened, most of the material fell to the center of the cloud and formed the sun.

Some of the condensing dust in the cloud became planets. The objects in the asteroid belt never had the chance to be incorporated into planets. They are leftovers from that time long ago when planets formed.

Are all asteroids the same?

No way! Because asteroids formed in different locations at different distances from the sun, no two asteroids are alike. Here are a few ways that they differ:

Asteroids aren't all round like planets. They have jagged and irregular shapes.

Some asteroids are hundreds of miles in diameter, but many more are as small as pebbles.

Most asteroids are made of different kinds of rocks, but some have clays or metals, such as nickel and iron.

What can we learn from asteroids?

Since asteroids formed at the same time as other objects in our solar system, these space rocks can give scientists lots of information about the history of planets and the sun. Scientists can learn about asteroids by studying meteorites: tiny bits of asteroids that have flown through our atmosphere and landed on Earth's surface.

Several NASA space missions have also flown by and observed asteroids. The NEAR Shoemaker spacecraft landed on Eros, an asteroid near Earth, in 2001. Then, the Dawn spacecraft traveled to the asteroid belt in 2011. It orbited and studied the giant asteroid Vesta and the dwarf planet Ceres.

In 2016, NASA launched the OSIRIS-REx spacecraft to study an asteroid near Earth named Bennu. After studying Bennu for a few years, OSIRIS-REx scooped up a sample of dust and rocks from the asteroid's surface.

Now, OSIRIS-REx is headed back to Earth! Its sample container will land in the Utah desert in September 2023. Scientists will then collect the container and examine the dust and rocks for clues about how planets formed and life began.

Will an asteroid ever hit Earth?

There are no known impact threats, but tiny meteors burn up in Earth's atmosphere all the time! Watch this video to learn more from NASA asteroid expert Dr. Kelly Fast.

Related Resources for Educators

Asteroid Resources from NASA JPL Education

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And what can we learn from these space rocks in our solar system?

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A star is a hot, glowing ball of gas. When you look up in the night sky, you can see countless twinkling stars. Can you see any stars during the daytime? Of course! The light of daytime comes from our closest star: the Sun.

Just how close is the Sun to Earth? Way, way closer than other stars, but still pretty far away. It's approximately 93 million miles away from Earth. That's 400 times farther than the distance between Earth and the Moon!

However, it's a good thing that Earth isn't too close to the Sun. If we were too close, it would be way too hot to live here. The Sun's surface is very hot, and its atmosphere is even hotter. And the Sun's core is the hottest part of all, at a sizzling 27 million degrees Fahrenheit!

Our Sun is about 100 times wider than Earth, but it is just an average sized star. Astronomers have found some stars that are 100 times bigger than the Sun and others that are 10 times smaller.

The Sun is also right in the middle of its lifecycle. Right now, our Sun is in a stage called yellow dwarf. It is about 4.5 billion years old. In another 5 billion years the Sun will become a big, cool star called a red giant. A few billion years after that, it will become a small white dwarf star. It will shrink to around the same size as Earth, but it will weigh 20,000 times more.

But even though our Sun is kind of an ordinary star, there are also a few things that make our Sun quite special. For example...

We can't live without the Sun!

Life on Earth depends on the Sun. Here are just a few reasons why:

The Sun's gravity holds our entire solar system together. Our solar system is even named after the Sun (the Latin word for Sun is "sol").

Heat from the Sun makes Earth warm enough to live on.

Without light from the Sun, there would be no plants or animals-and, therefore, no food and we wouldn't exist.

Heat and light might be important for life on Earth, but the Sun sends other stuff, too. The Sun sends lots of other energy and small particles toward Earth. Earth's protective magnetic field and atmosphere shields us from most of the energy and particles. But sometimes a big stream of these particles reaches Earth and interacts with the gases at the outer edge of our atmosphere. This causes streams of light in the sky, called auroras.

The Sun's Neighbors

In our solar system, the closest planet to the Sun is Mercury. Our Sun's closest star neighbor is called Proxima Centauri. It is approximately 4 light-years away.

What does the Sun look like?

First of all, you should never look directly at the Sun without very special protective eyewear. But NASA has many great pictures of the Sun for you to look at! Scientists use telescopes with filters to capture images of the Sun. These images help us learn about our star. The photo below was taken by a NASA spacecraft called the Solar Dynamics Observatory.

Have any spacecraft visited the Sun?

A spacecraft would easily burn up if it tried to fly into the Sun. However, NASA's Parker Solar Probe is flying closer than any other robotic explorer ever has. It will be flying inside the Sun's atmosphere, or corona. This spacecraft will help us learn more about how the Sun works and how solar activity starts. This helps us to be more prepared!

More fun facts about the Sun!

The Sun goes through ups and downs in activity like solar flares. It gets more active with more sunspots and then less active over a period of 11 years. This is called the solar cycle.

The Sun has been getting slowly brighter since it was born. A couple of billions of years ago, the Sun was a little dimmer than it is now.

The Sun contains almost ALL of the material in our solar system. 99% of it. All the planets, asteroids and comets add up to less than 1% of the total.

The Sun is so far away that it takes light about 8 minutes and 20 seconds for it to get to us - and light is the fastest thing in the universe.

For more information visit:
NASA Science

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The light of daytime comes from our closest star: the Sun. Learn more about it!

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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Kids learn about the planet Mars of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

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Kids learn about the planet Venus of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

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Kids learn about the planet Jupiter of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

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All About Pluto and Dwarf Planets for Kids: Astronomy and Space for Children - FreeSchool

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Guide to Dwarf Planets: Ceres, Pluto, Eris, Haumea and Makemake for Kids - FreeSchool

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Kids learn about the planet Saturn of the Solar System including its rings, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

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Kids learn about the ice giant planet Uranus of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

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Kids learn about the ice giant planet Neptune of the Solar System including fun facts, mass, day, year, and distance from the Sun. Astronomy for kids and teachers.

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Astronomy for Kids: Learn about the Dwarf Planet Pluto

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Kids astronomy. What is Pluto like? How do we know about this dwarf planet? Why is Pluto no longer considered a full planet of the Solar System?

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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Saturn’s moons includes stunning images. Learn more about Saturn’s moons at DK Find Out!

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Saturn’s moons includes stunning images. Learn more about Saturn’s moons at DK Find Out!

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DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

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Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

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Planet Mercury Overview Mercury-the smallest planet in our solar system and nearest to the Sun-is only slightly larger than Earth's Moon. Its surface is covered in tens of thousands of impact craters. From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and [...]

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Mercury is the smallest planet in our solar system. It's just a little bigger than Earth's moon. It is the closest planet to the sun, but it's actually not the hottest. Venus is hotter.

Along with Venus, Earth, and Mars, Mercury is one of the rocky planets. It has a solid surface that is covered with craters. It has no atmosphere, and it doesn't have any moons. Mercury likes to keep things simple.

This small planet spins around slowly compared to Earth, so one day lasts a long time. Mercury takes 59 Earth days to make one full rotation. A year on Mercury goes by fast. Because it's the closest planet to the sun, it doesn't take very long to go all the way around. It completes one revolution around the sun in just 88 Earth days. If you lived on Mercury, you'd have a birthday every three months!

A day on Mercury is not like a day here on Earth. For us, the sun rises and sets each and every day. Because Mercury has a slow spin and short year, it takes a long time for the sun to rise and set there. Mercury only has one sunrise every 180 Earth days! Isn't that weird?

Structure and Surface

Mercury is the smallest planet in our solar system.

Mercury is a terrestrial planet. It is small and rocky.

Mercury doesn't really have an atmosphere.

Time on Mercury

A day on Mercury lasts 59 Earth days.

A year on Mercury lasts 88 Earth days.

Mercury's Neighbors

Mercury does not have any moons.

Mercury is the closest planet to the sun.

Venus is Mercury's neighboring planet.

Quick History

Mercury has been known since ancient times because it can be seen without advanced telescopes.

Mercury has been visited by two spacecraft: Mariner 10 and MESSENGER.

What does Mercury look like?

For more information visit:
NASA Solar System Exploration

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Mars is a dusty, cold, desert world with a very thin atmosphere.

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Jupiter is the fifth planet from our Sun and is, by far, the largest planet in the solar system - more than twice as massive as all the other planets combined.

Jupiter's stripes and swirls are actually cold, windy clouds of ammonia and water, floating in an atmosphere of hydrogen and helium. Jupiter's iconic Great Red Spot is a giant storm bigger than Earth that has raged for hundreds of years.

Jupiter is named for the king of the ancient Roman gods.​

The biggest planet in our solar system has a large presence in pop culture, including many movies, TV shows, video games, and comics. Jupiter and its moons were notable destinations in "The Expanse" series, while various Jovian moons provide settings for "Cloud Atlas," "Futurama," "Power Rangers," and "Halo," among many others. In the movie "Men in Black" when Agent J - played by Will Smith - mentions he thought one of his childhood teachers was from Venus, Agent K - played by Tommy Lee Jones - replies that she is actually from one of Jupiter's moons.

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Jupiter is the fifth planet from our Sun and is, by far, the largest planet in the solar system - more than twice as massive as all the other planets combined. Its iconic Great Red Spot is a giant storm bigger than Earth, and has raged for hundreds of years.

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Saturn is the sixth planet from the Sun and the second largest planet in our solar system. Adorned with a dazzling system of icy rings, Saturn is unique among the planets.

It is not the only planet to have rings, but none are as spectacular or as complex as Saturn's. Like fellow gas giant Jupiter, Saturn is a massive ball made mostly of hydrogen and helium.

The farthest planet from Earth discovered by the unaided human eye, Saturn has been known since ancient times. The planet is named for the Roman god of agriculture and wealth, who was also the father of Jupiter.

Perhaps the most iconic of all the planets in our solar system, Saturn is heavily present in pop culture.

It provides a backdrop for numerous science fiction stories, movies, and TV shows, comics, and video games, including the "Cthulhu Mythos," "WALL-E," "2001: A Space Odyssey," and "Star Trek." In Tim Burton's film "Beetlejuice," a dusty, fictional Saturn is populated by giant sandworms. And in the 2014 movie "Interstellar," the wormhole that enables the astronauts to travel to another galaxy appears near Saturn.

Saturn is also the namesake of Saturday, arguably the best day of the week.​

Discover More Topics From NASA

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Planet Saturn Overview Saturn is the sixth planet from the Sun and the second largest planet in our solar system. Adorned with a dazzling system of icy rings, Saturn is unique among the planets. It is not the only planet to have rings, but none are as spectacular or as complex as Saturn's.

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Uranus is the seventh planet from the Sun, and has the third-largest diameter in our solar system. It was the first planet found with the aid of a telescope, Uranus was discovered in 1781 by astronomer William Herschel, although he originally thought it was either a comet or a star.

It was two years later that the object was universally accepted as a new planet, in part because of observations by astronomer Johann Elert Bode. Herschel tried unsuccessfully to name his discovery Georgium Sidus after King George III. Instead, the scientific community accepted Bode's suggestion to name it Uranus, the Greek god of the sky, as suggested by Bode.​

Go Farther

Everything you need to know about Uranus.

Uranus In Depth

Ten Things to Know About Uranus
Pop Culture

Uranus is the source of more than a few jokes and witty (and not so witty) puns, but the ice giant and its moons has been a serious destination various fictional stories, and on TV shows such as "Doctor Who." The radioactive element uranium was named after Uranus when it was discovered in 1789, just eight years after the planet was discovered.

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The seventh planet from the sun with the third largest diameter in our solar system, Uranus is very cold and windy.

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Planet Neptune Overview Dark, cold and whipped by supersonic winds, giant Neptune is the eighth and most distant major planet orbiting our Sun. More than 30 times as far from the Sun as Earth, Neptune is not visible to the naked eye. In 2011, Neptune completed its first 165-year orbit since its discovery.

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There are more planets than stars in our galaxy. The current count orbiting our star: eight.

The inner, rocky planets are Mercury, Venus, Earth and Mars. NASA's newest rover - Perseverance - landed on Mars on Feb. 18, 2021. The outer planets are gas giants Jupiter and Saturn and ice giants Uranus and Neptune.

Beyond Neptune, a newer class of smaller worlds called dwarf planets reign, including longtime favorite Pluto. Thousands more planets have been discovered beyond our solar system. Scientists call them exoplanets (exo means "from outside.")

Planets of our Solar System

What is a Dwarf Planet?

They key difference between a planet and a dwarf planet is the kinds of objects that share its orbit around the Sun. Pluto, for example, has not cleared its orbit of similar objects while Earth or Jupiter have no similarly-sized worlds on the same path around the Sun. Like planets, dwarf planets are generally round (Haumea looks like an overinflatred football) and orbit the Sun.

There are likely thousands of dwarf planets waiting to be discovered beyond Neptune. The five best known dwarf planets are: Ceres, Pluto, Makemake, Haumea and Eris. Except for Ceres, which lies in the main asteroid belt, these small worlds are located in the Kuiper Belt. They're considered dwarfs because they are massive, round, and orbit the Sun, but haven't cleared their orbital path.

Real-Time, Interactive Solar System

Real-Time, Real Data: Your Galactic Neighborhood

This simulated view of our solar system at the top of this page (and below) runs on real data. The position of the planets, moons and spacecraft are shown where they are right now. This digital orrery (a model of the solar system) runs on a light, mobile-mobile friendly version of NASA's Eyes on the Solar System software.

This snapshot focuses on active NASA missions and select ESA missions. Showcasing the entire operating international fleet is too much of a data wallop at the moment (but we are working on it!). Active international missions such as Japan's Akatsuki Venus Orbiter and ESA and Japan's Mercury-bound BepiColombo are not yet available.

Use the HD button to upload higher resolution imagery of the planets. It may not work properly on older mobile devices. Have fun, and keep exploring.

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There are more planets than stars in our galaxy. The current count orbiting our star: eight. The inner, rocky planets are Mercury, Venus, Earth and Mars. NASA's newest rover - Perseverance - landed on Mars on Feb. 18, 2021. The outer planets are gas giants Jupiter and Saturn and ice giants Uranus and Neptune.

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These rocky fragments are leftovers from the beginning of our solar system.

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Moons come in many shapes, sizes, and types. A few have atmospheres and even hidden oceans beneath their surfaces.

How Many Moons Are in Our Solar System?

Naturally-formed bodies that orbit planets are called moons, or planetary satellites. The best-known planetary satellite is, of course, Earth's Moon. Since it was named before we learned about other planetary satellites, it is called simply "Moon."

According to the NASA/JPL Solar System Dynamics team, the current tally of moons orbiting planets in our solar system is 293: One moon for Earth; two for Mars; 95 at Jupiter; 146 at Saturn; 28 at Uranus; 16 at Neptune; and five for dwarf planet Pluto.

Astronomers also have documented more than 470 satellites, or moons, orbiting smaller objects, such as asteroids, dwarf planets, or Kuiper Belt Objects (KBOs) beyond the orbit of Neptune. These moons are called s mall-body satellites.

Most planetary moons probably formed from the discs of gas and dust circulating around planets in the early solar system, though some are captured objects that formed elsewhere and fell into orbit around larger worlds.

Scientists are very good at spotting tiny moons orbiting distant, giant planets. So many tiny moons have been found that the International Astronomical Union, which governs official names of planets and moons, will no longer name the smallest moons unless they're of "significant" scientific interest. There are likely thousands more moons awaiting discovery in our solar system.

Moons in Our Solar System Stories

Moons in our Solar System

NASA - Pluto and Its Moons: Charon, Nix and Hydra

A pair of small moons orbiting Pluto, which were discovered by NASA's Hubble Space Telescope

Discovered in 2005, the two moons are roughly 5,000 times fainter than Pluto and are about two to three times farther from Pluto than its large moon, Charon, which was discovered in 1978.
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Hubble Discovers a Fifth Moon Orbiting Pluto

A team of astronomers using NASA's Hubble Space Telescope is reporting the discovery of another moon orbiting the icy dwarf planet Pluto.

The moon is estimated to be irregular in shape and 6 to 15 miles across. It is in a 58,000-mile-diameter circular orbit around Pluto that is assumed to be co-planar with the other satellites in the system.
Read More

If you lived on one of Pluto's moons, you might have a hard time determining when, or from which direction,...
Read the Story

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How Many Moons Are in Our Solar System? Naturally-formed bodies that orbit planets are called moons, or planetary satellites. The best-known planetary satellite is, of course, Earth's Moon. Since it was named before we learned about other planetary satellites, it is called simply "Moon." According to the NASA/JPL Solar System Dynamics team, the current tally [...]

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Venus is the second planet from the Sun and is Earth's closest planetary neighbor. It's one of the four inner, terrestrial (or rocky) planets, and it's often called Earth's twin because it's similar in size and density. These are not identical twins, however - there are radical differences between the two worlds.

Venus has a thick, toxic atmosphere filled with carbon dioxide and it's perpetually shrouded in thick, yellowish clouds of sulfuric acid that trap heat, causing a runaway greenhouse effect. It's the hottest planet in our solar system, even though Mercury is closer to the Sun. Surface temperatures on Venus are about 900 degrees Fahrenheit (475 degrees Celsius) - hot enough to melt lead. The surface is a rusty color and it's peppered with intensely crunched mountains and thousands of large volcanoes. Scientists think it's possible some volcanoes are still active.

Venus has crushing air pressure at its surface - more than 90 times that of Earth - similar to the pressure you'd encounter a mile below the ocean on Earth.

Another big difference from Earth - Venus rotates on its axis backward, compared to most of the other planets in the solar system. This means that, on Venus, the Sun rises in the west and sets in the east, opposite to what we experience on Earth. (It's not the only planet in our solar system with such an oddball rotation - Uranus spins on its side.)

Venus was the first planet to be explored by a spacecraft - NASA's Mariner 2 successfully flew by and scanned the cloud-covered world on Dec. 14, 1962. Since then, numerous spacecraft from the U.S. and other space agencies have explored Venus, including NASA's Magellan, which mapped the planet's surface with radar. Soviet spacecraft made the most successful landings on the surface of Venus to date, but they didn't survive long due to the extreme heat and crushing pressure. An American probe, one of NASA's Pioneer Venus Multiprobes, survived for about an hour after impacting the surface in 1978.

More recent Venus missions include ESA's Venus Express (which orbited from 2006 until 2016) and Japan's Akatsuki Venus Climate Orbiter (orbiting since 2016).

NASA's Parker Solar Probe has made multiple flybys of Venus. On Feb. 9, 2022, NASA announced the spacecraft had captured its f irst visible light images of the surface of Venus from space during its February 2021 flyby.

As Parker Solar Probe flew by Venus in February 2021, its WISPR instrument captured these images, strung into a video, showing the nightside surface of the planet. Credit: NASA/APL/NRL

In June 2021, three new missions to Venus were announced. NASA announced two new missions, and ESA announced one:

VERITAS: NASA's VERITAS, or Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy, will be the first NASA spacecraft to explore Venus since the 1990s. The spacecraft will launch no earlier than December 2027. It will orbit Venus, gathering data to reveal how the paths of Venus and Earth diverged, and how Venus lost its potential to be a habitable world.

DAVINCI: NASA's DAVINCI mission will launch in the late 2020s. After exploring the top of Venus's atmosphere, DAVINCI will drop a probe to the surface. On its hour-long descent, the probe will take thousands of measurements and snap up-close images of the surface. The probe may not survive the landing, but if it does, it could provide several minutes of bonus science.

EnVision: ESA has selected EnVision to make detailed observations of Venus. As a key partner in the mission, NASA is providing the Synthetic Aperture Radar, called VenSAR, to make high-resolution measurements of the planet's surface features.

Go Farther

Everything you need to know about Venus.

Venus In Depth

Ten Things to Know About Venus
Pop Culture

Because it's so bright and easy to see in the sky, Venus has played a role in popular culture since ancient times, inspiring writing and song:

It was called the most beautiful star in the sky by Homer, author of "The Iliad" and "The Odyssey" - two of the oldest and most important works in Greek literature.

More recently, Venus became a popular venue for 20th-century science fiction writers, including Edgar Rice Burroughs ("Pirates of Venus," 1934); Arthur C. Clarke ("Before Eden," 1961); and C.S. Lewis ("Perelandra," 1943).

Australian author Shirley Hazzard won the 1980 National Book Critics Circle Award for fiction with her book, "The Transit of Venus," about two orphaned sisters. American author John Gray used the planet and its masculine counterpart to explain relationships in his 1992 book "Men Are From Mars, Women Are From Venus."

A song called "Venus" was teen idol Frankie Avalon's first No. 1 hit when it topped the Billboard Hot 100 chart in 1959. A decade later, a different song called "Venus" by the Dutch rock band Shocking Blue topped the charts in several countries. In 1986, British pop group Bananarama had a No. 1 hit in the U.S. with their cover of the song.

More recently, Venus has been a backdrop for video games such as Transhuman Space, Battlezone, and Destiny. And in the Disney animated film "The Princess and the Frog," Ray the firefly falls in love with Venus, "the evening star," as he has mistaken it for another firefly.

Kid-Friendly Venus

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Venus is the second planet from the sun and our closest planetary neighbor.

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Jupiter's Moons: Crash Course Astronomy #17

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How Saturn's Moons Could Help Us Live in Space

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Newsela | Exploring The Planets: Mercury

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Mercury is the smallest of the planets in our solar system. Similar to Earth's moon, it has a rocky surface with impact craters and plunging cliffs. The temperature shifts dramatically between day and night, making the planet inhospitable for human life.

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Venus is the closest planet to Earth and is also the most similar in size, mass and volume.

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Newsela | Exploring The Planets: Jupiter

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Saturn, the second-largest planet in the solar system, is best known for its amazing rings.

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Facts about Uranus, including its size and distance from the sun, the gases it is made of, its dark rings and more

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Newsela | Exploring The Planets: Neptune

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Neptune is huge and stormy and has the fastest winds ever discovered in the solar system.

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Newsela | Exploring Our Solar System: The dwarf planet Pluto

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Pluto is a dwarf planet, and its oval orbit, small size and other features make it unlike the eight planets.

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Kid's learn about the science of stars like our Sun. Giant hot balls of gas and energy made mostly of hydrogen and helium.

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The Sun is the star in the center of our solar system. It is a yellow dwarf star. It gives off energy as light. That includes light, infra-red energy (heat), ultraviolet light and radio waves. It also gives off a stream of particles, which reaches Earth as " solar wind". The source of all this energy is nuclear fusion. Nuclear fusion is the reaction in the star which turns hydrogen into helium and makes huge amounts of energy.

The Sun is a star like many others in our Milky Way galaxy. The Sun is a type of star called a G-type main-sequence star based on its spectral class. It has existed for a little over 4.5 billion years. It is going to continue for at least as long. The Sun is about a hundred times as wide as the Earth. It has a mass of . This is 333,000 times the mass of the Earth. 1.3 million Earths can fit inside the Sun.

Scientists think that the Sun started from a very large cloud of dust and small bits of ice about 4.567 billion years ago.

At the center of that huge cloud, gravity caused the material to build up into a ball. Once this got big enough, the huge pressure inside started a fusion reaction. The energy this released caused that ball to heat and shine.

The energy radiated from the Sun pushed away the rest of the cloud from itself, and the planets formed from the rest of this cloud.

Composition

The Sun is mainly composed of hydrogen and helium. All elements heavier than hydrogen and helium, accounts for less than 2% of the mass of the Sun.

Photosphere

Atmosphere

Five layers make up the atmosphere of the Sun. The chromosphere, transition region, and corona are much hotter than the outer photosphere surface of the Sun. It is believed that Alfvén waves may pass through to heat the corona.

The minimum temperature zone, the coolest layer of the Sun, is about 500 kilometres (310 miles) above the photosphere. It has a temperature of about 4,100 K (3,830 °C; 6,920 °F). This part of the Sun is cool enough to allow simple molecules such as carbon monoxide and water to form. These molecules can be seen on the Sun with special instruments called spectroscopes.

The chromosphere is the first layer of the Sun which can be seen, especially during a solar eclipse when the moon is covering most of the Sun and blocking the brightest light.

The solar transition region is the part of the Sun's atmosphere, between the chromosphere and outer part called the corona. It can be seen from space using telescopes that can sense ultraviolet light. The transition is between two very different layers. In the bottom part it touches the photosphere and gravity shapes the features. At the top, the transition layer touches the corona.

The is the outer atmosphere of the Sun and is much bigger than the rest of the Sun. The corona continuously expands into space forming the solar wind, which fills all the Solar System. The average temperature of the corona and solar wind is about 1,000,000-2,000,000 K (1,800,000-3,600,000 °F). In the hottest regions it is 8,000,000-20,000,000 K (14,400,000-36,000,000 °F). We do not understand why the corona is so hot. It can be seen during a solar eclipse or with an instrument called a coronagraph.

The heliosphere is the thin outer atmosphere of the Sun, filled with the solar wind plasma. It extends out past the orbit of Pluto to the heliopause, where it forms a boundary where it collides with the interstellar medium.

Visible features

Sunspots, prominences and flares become rare, and then numerous, and then rare again, every 11 years.

A solar eclipse appears when the moon is between the Earth and Sun. The last total solar eclipse occurred on Dec. 26, 2019, and was visible from Saudi Arabia, India, Sumatra and Borneo, with a partial eclipse visible in Australia and much of Asia.

A lunar eclipse happens when the moon passes through the shadow of the Earth which can only occur during a full moon.The number of lunar eclipses in a single year can range from 0 to 3. Partial eclipses slightly outnumber total eclipses by 7 to 6.

Solar weather

Solar weather affects us on Earth. Solar weather (also called space weather) includes sunlight and the solar wind. Solar flares shoot a lot of very hot gas out from the Sun. If a solar flare is aimed towards Earth, protons - subatomic particles with positive electric charge - can be shot at Earth at high speed, and a solar storm could result. This could cause electrical blackouts or block radio signals. It damages satellites in orbit. Radiation from an extreme solar storm could be very dangerous for astronauts, so they must be protected. The Earth's magnetic field and atmosphere usually protect us from flares.

Solar flares can also cause an aurora. Auroras look like beautiful curtains of shimmering light. They are called Northern Lights (Aurora Borealis) if they are near the North Pole. They are called Southern Lights (Aurora Australis) if they are near the South Pole. Solar weather affects other planets, too. We have pictures of auroras on every planet except Mercury and Pluto.

Just like we can get Earth weather forecasts, we can get Solar weather forecasts. Forecasters study the Sun to figure out when flares will happen. They try to tell when solar storms will hit Earth. They also try to tell when solar storms will go to other parts of the Solar System.

Planetary system

The Sun has eight known planets. This includes four terrestrial planets ( Mercury, Venus, Earth, and Mars), two gas giants ( Jupiter and Saturn), and two ice giants ( Uranus and Neptune). The Solar System also has at least five dwarf planets, an asteroid belt, numerous comets, and a large number of icy bodies which lie beyond the orbit of Neptune.

Observation and effects

The brightness of the Sun can cause pain from looking at it with the naked eye; however, doing so for brief periods is not hazardous for normal non-dilated eyes.

Viewing the Sun through light-concentrating optics such as binoculars may result in permanent damage to the eyes.

Partial solar eclipses are hazardous to view because the eye's pupil is not adapted to the unusually high visual contrast.

Ultraviolet light from the Sun has antiseptic properties and can be used to sanitize tools and water. It also causes sunburn, and has other biological effects such as the production of vitamin D and sun tanning.

Exploration of the Sun

Early space probes designed to collect information about the sun were NASA's Pioneers 5 through 9 and the Helios 1 and 2. Those were in the 1950s, 60s, and 70s. They collected a lot of data about the Sun. The Parker Solar Probe is a NASA robotic spacecraft launched in 2018 and currently en route to probe the outer corona of the Sun. It will approach to within 9.86 solar radii (6.9 million kilometers or 4.3 million miles) from the center of the Sun and by 2025 will travel, at closest approach, as fast as 690,000 km/h (430,000 mph), or 0.064% the speed of light.

A memory card containing the names of over 1.1 million people was mounted on a plaque and installed below the spacecraft's high-gain antenna on May 18, 2018. The card also contains photos of Parker and a copy of his 1958 scientific paper predicting important aspects of solar physics.

On 29 October 2018 at about 1:04 p.m. EDT, the spacecraft became the closest ever man-made object to the Sun. The previous record, 26.55 million miles from the Sun's surface, was set by the Helios 2 spacecraft in April 1976.

Fate of the Sun

Astrophysicists say our Sun is a G-type main-sequence star in the middle of its life. In a billion years or so, increased solar energy will boil away the Earth's atmosphere and oceans. In a few more billion years, they think the Sun will get bigger and become a red giant star. The Sun would be up to 250 times its current size, as big as 1.4 AU (210,000,000 kilometres; 130,000,000 miles) and will swallow up the Earth.

Earth's fate is still a bit of a mystery. In the long term, the Earth's future depends on the Sun, and the Sun is going to be fairly stable for the next 5 billion years. Calculations suggest that the Earth might move to a wider orbit. This is because about 30% of the Sun's mass will blow away in the solar wind. However, in the very long term the Earth will probably be destroyed as the Sun increases in size. Stars like the Sun become red giants at a later stage. The Sun will expand beyond orbits of Mercury, Venus, and probably Earth. In any event, the ocean and air would have vanished before the Sun gets to that stage.

Images for kids

In Spanish: Sol para niños

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On a clear night we can see what looks like thousands of stars in the sky. The fact is, there are actually trillions of stars in the sky. Many are so far away we cannot see them without a special telescope. Scientists think the universe is so large that even with special telescopes, they are not even close to being able to see all the stars in the universe. Find out many different interesting facts about stars.

Our sun, the center of our solar system, is a star.

Stars are suns, but they are very far away from Earth, so they look very small.

Our sun is an average size sun.

Some stars are much larger than our sun. A star known as W26 is probably the largest star that astronomers have identified. Scientists estimate that W26 is about 1500 times larger than our sun. W26, which is a red supergiant star, is located in the Milky Way about 14,000 light years from Earth.

W26 is not the closest star to Earth. Alpha Centauri is the closest star to Earth at a distance of 24 trillion miles (38 trillion kilometers) or 4 light years away.

Stars also have different colors. The color of the star is related to its temperature and how long the star will burn.

The hottest stars are blue or white.

Yellow stars have a medium temperature. Our sun is a yellow star and is about 60,000 K at the surface.

The coolest stars are orange and red stars.

Blue stars, which are also the hottest stars, burn out the quickest.

White and yellow stars have an average life span.

Scientists think that red stars burn the longest.

As they age, giant, very bright stars like giant blue stars will swell into a supergiant. They will then explode and when they do, scientists call them a supernova. Soon after, the supernova will collapse to form a black hole. Black holes are very dense material with an extremely high gravitational pull. The gravity in a black hole is so great that even light cannot escape.

A supernova is very bright. It may be brighter during its last few seconds than the total light released by our sun over the next 200 million years.

A pulsar is the result of when a hot giant star explodes. A tiny spinning neutron star sometimes results from this type of exploding star. A pulsing flash of light is given off by a pulsar. The light is so great that astronomers are able to see pulsars a great distance away using a telescope.

Neutron stars have extremely high magnetic fields. Scientists think that a neutron star may have a magnetic field trillions of times stronger than our sun.

Nebula is clouds of dust and gas in space. Some nebula is the result of stars that exploded.

Astronomers are not sure if all stars have planets like our own solar system. Planets are very difficult to see over long distances, so until we have better telescope technology, we may not know the answer.

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Learn some facts about stars to help teach about space and astronomy. Scientists study the stars to help them understand how the universe may have been created. Studying the stars also helps us to understand how large is the universe.

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How big is the Sun?

The Sun is the biggest object in our solar system, with a distance of 695,508 kilometres from centre to surface. It contains 99.86% of the mass of the entire solar system and could contain roughly 1.3 million Earths.

The Sun is an average-sized star. Some stars are just a tenth of its size, while others are more than 700 times bigger. Due to its huge mass and strong gravity, the Sun is a near perfect sphere.

How hot is the Sun?

The core is the hottest part of the Sun, at 15 million degrees Celsius. This is hot enough to sustain thermonuclear fusion, when hydrogen atoms are fused together to form larger helium atoms. This releases an extraordinary amount of energy which in turn is released as heat and light.

The energy produced at the core takes up to a million years to reach the outer layer known as the convective zone. At this point the temperature drops to around two million degrees Celsius. By the time it gets to the surface the temperature is down to a much cooler 5,973°C - but it's still hot enough to boil diamonds.

In the Sun's atmosphere, known as the corona, the temperature begins to rise again to roughly two million degrees Celsius. As distance from the core of the Sun grows wider, the temperature would be expected to drop. This dramatic increase in temperature in the atmosphere is one of the star's biggest mysteries.

What is the Sun made of?

The Sun is a ball of gas and plasma - around 91% of it is hydrogen gas. Under intense heat and gravitational force this is fused into helium during nuclear fusion.

When the plasma is heated to the temperatures seen on the Sun, it contains so much energy that the charged particles can escape the star's gravity and blow out into space. This is called solar wind - under certain conditions, when it hits Earth's atmosphere it can cause auroras, such as the Northern Lights.

In addition to hydrogen and helium, scientists have detected at least 65 other elements in the Sun. The most abundant of these include oxygen, carbon, nitrogen, silicon, magnesium, neon, iron, and sulphur.

Does the Sun rotate?

Yes. Even though the Sun is not solid like Earth, it still has a rotation as the plasma swirls around its surface. On average, it takes 27 Earth days for the Sun to rotate once on its axis, but different parts move at different speeds. The equatorial regions take just 24 days to rotate and the polar regions more than 30.

What are sunspots?

Sunspots are cooler parts of the Sun's surface, and occur in the photosphere. The temporary splodges across the surface appear darker to us than the warmer plasma surrounding it.

These cooler spots can be up to 50,000 kilometres across. They are thought to be caused by interactions with particularly strong regions of the underlying magnetic field, which slightly reduce the radiation coming up from the core, cooling the surface.

What are solar flares?

Solar flares are the largest explosive events in the entire solar system. They occur when the magnetic fields associated with the sunspots convert energy into heat and accelerating particles, ejecting it into space.

They are characterised by a burst of photons - or light - at almost every wavelength. Scientists usually measure the ultraviolet rays, X-rays and gamma-rays coming from the solar flares. These typically show up as bright flashes on the surface of the Sun, and can last from just a couple of minutes to a few hours.

What type of star is the Sun?

The Sun is currently a yellow dwarf. Like all stars, it began as a contracting nebula - effectively a cloud of dust and gas.

As each particle has its own tiny gravitational pull, the dust and gas began to coalesce into a protostar. As this mass is pulled together and collapses in on itself it generates heat. If it becomes big enough it will eventually get sufficiently hot to fuse hydrogen into helium. This was how the Sun formed.

The celestial object then enters its main sequence stage, during which the outward pressure of nuclear fusion is balanced by the inward pressure of the stars own gravity. The Sun is currently in this stable phase.

When will the Sun explode?

It won't. When all of the hydrogen in its core is burned up, it exits the main sequence stage.

As a relatively small star, the outer layers of the Sun will collapse in on themselves, creating temperatures hot enough to fuse helium into carbon. At this point the pressure will cause the star to rapidly expand outward to form a red giant.

For the Sun, this is expected to occur in about five billion years. It is likely to engulf Mercury and Venus - and potentially even the Earth.

It will eventually shrink to become a planetary nebula with a white dwarf at its core.

Where is the Sun in the Milky Way?

There are an estimated 100 billion galaxies in the known universe. The Sun and its eight planets, including Earth, reside in one known as the Milky Way. Our galaxy is around one quintillion kilometres across, or 100,000 light years.

The Sun is in a spiral arm of the Milky Way called the Orion Spur. This branches off from the galaxy's Sagittarius arm. The Sun and our solar system are orbiting around the centre of the Milky Way at a speed of 720,000 kilometres per hour. It takes 230 million years to make one complete orbit.

What is a solar eclipse?

Sometimes the Moon comes between the Sun and Earth. If all three are aligned, the Moon can block the Sun entirely, casting a shadow on Earth and causing a solar eclipse. This is because even though the Sun is 400 times larger than the Moon, the Moon is 400 times closer to Earth.

Solar eclipses occur roughly every six months, but total solar eclipses, in which the Sun is completely obscured by the Moon, are much rarer. They tend to occur around every two years, although often in remote areas of the Earth. These total eclipses can last for as little as a few seconds, but never longer than seven minutes.

How do we study the Sun?

Due to its extreme temperatures studying the Sun with spacecrafts is incredibly difficult. We have to rely on observations using telescopes and cameras on Earth satellites.

However, in 2020 the European Space Agency and NASA launched the Solar Orbiter, which will enter an elliptical orbit of the Sun allowing unprecedented observations.

After taking three and a half years to reach the Sun, it will begin a seven year mission to study the stars solar wind, magnetic fields, and plasma. It will orbit as close as 42 million kilometres from the Sun's surface, closer even than Mercury.

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Explore facts about the Sun, the star at the centre of our solar system. Discover how big and hot it is, what it's made of and what sunspots and solar flares are. Plus, what is the future for the Sun - will it explode?