The Solar System's planets

The Solar System has 8 planets. Their names are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. This post will teach you all about them.

Mercury

Mercury is the 1st planet from the Sun, which means it is the closest to the Sun. It has no moons. It is the smallest planet in the Solar System, and is covered with craters. Mercury orbits the Sun in only 88 days. That is faster than any planet.

Mercury cannot support life. During the day, it is super hot, and during the night, it is super cold. Mercury is a rocky inner planet, which means that a spacecraft could land on its surface, and an astronaut could stand on its surface. They probably would not want to, due to the planet’s extreme temperatures.

Fun facts

It would take about six years for a spacecraft to travel to Mercury from Earth.

Venus

Venus is the 2nd planet from the Sun. It has no moons. You would think that Mercury was the hottest planet, because it is closest to the Sun. If you think that, you are wrong. Venus is the hottest planet. Why is that? Venus has the thickest atmosphere of all the planets. This thick atmosphere holds in heat, making the planet very, very, very hot.

Not only is Venus the hottest planet, it is also the brightest planet. Venus is surrounded by thick clouds. Sunlight bounces off of these clouds, making the planet appear to glow. Venus will look like the brightest star in the night sky.

Venus has many volcanoes. In fact, it has so many that scientists think that it has the most volcanoes in the Solar System.

Mercury spins counter-clockwise, and the Sun rises in the east and sets in the west. But Venus spins clockwise, meaning that the Sun rises in the west and sets in the east. Only two planets spin clockwise.

Fun facts

It would take about six months for a spacecraft to travel to Venus from Earth.

Venus is so hot that sometimes it looks like it glows in the dark!

Earth

Earth is the 3rd planet from the Sun. It has one moon. Earth is about the same size as Venus, meaning it has about the same amount of gravity. Earth is the largest of the inner planets. Earth is also the fifth biggest planet in the Solar System.

Earth is the only planet in the Solar System that can support life. To support life, a planet needs three things: oxygen, water, and food. Earth has all of these things.

There is a very interesting story about how Earth’s moon was created. Some scientists think that, when the planet was young, an object the size of Mars crashed into Earth, sending a large amount of debris into space. Over time, the debris joined together to form the moon.

Only one-third of Earth’s surface is dry land. Everything else is oceans. Earth’s oceans are so big that Earth looks like a blue marble from space.

All the planets go around the Sun on a fixed path, called an orbit. It takes Earth one year, or 365.24 days, to orbit the Sun. Since it does not take exactly 365 days to orbit the Sun, an extra day is added to the month of February every 4 years. These years are called leap years.

Fun facts

It would take about two days for a spacecraft to get to the Moon from Earth.

Earth’s core is so hot that it can melt rock and turn it into liquid.

Mars

Mars is the 4th planet from the Sun. It has two moons, Deimos and Phobos. Some scientists think that in a few million years, one of Mars’s moons will crash into the planet, and the other will float into space. Mars is nicknamed the “Red Planet”, because of its red, rusty dust.

Mars is home to the Solar System’s largest volcano, Olympus Mons. It is 16 miles (25.7 km) high and as wide as the Hawaiian islands.

Did you know that Mars has its own Grand Canyon? Well, it does! It is called the Mariner Valley. It is as long as the US is wide. It makes the Grand Canyon seem very small!

Scientists think Mars is more like Earth than any other planet in the Solar System. They believe that Mars used to have rivers, and maybe even an ocean, millions of years ago. They are still searching for water on Mars.

Fun facts

It would take about nine months for a spacecraft to travel to Mars from Earth.

Scientists believe that Mars’ moons were once asteroids.

Jupiter

Jupiter is the 5th planet from the Sun, and is the largest planet in the Solar System. It has at least 50 moons, possibly 67. All the outer planets have rings, and that includes Jupiter. Jupiter has thin, hard-to-see rings. Even though they’re so hard to see, the rings still have names. Their names are Gossamer, Main and Halo.

Jupiter’s stripes are formed from gases, storms and clouds.One of these storms has been raging for hundreds, maybe even thousands, of years. It is the size of about three Earths, and is called “The Great Red Spot”.

All the outer planets are almost completely of gases. This is why they are called “gas planets”. Jupiter’s surface is an ocean of different gases and water.

Jupiter’s four biggest moons, Europa, Io, Callisto, and Ganymede, can be seen at night with a pair of binoculars. Europa’s surface is mostly ice. Io has active volcanoes. Callisto is about the size of Mercury. Ganymede is the biggest moon in the Solar System.

Fun facts

If the Sun were as tall as a typical front door, Jupiter would be about as big as a basketball.

It would take about 13 months for a spacecraft to travel to Jupiter from Earth.

Saturn

Saturn is the 6th planet from the Sun and is the second-largest planet in the Solar System. It has at least 53 moons, possibly 62. 

The planet is sometimes called the “Lord of the Rings”, because of its beautiful rings. It has seven main rings made from icy particles. Some pieces of ice are as small as a speck of dust. Others are as large as mountains!

Titan, Saturn’s biggest moon, is covered in a thick, golden haze. Only very powerful telescopes and cameras can see through the haze to Titan’s surface.

Fun facts

If Saturn could be put in a big enough ocean, it would float!

If there were cars in space, it would take them over one week to drive across some of Saturn’s rings.

Uranus

Uranus is the 7th planet from the Sun. It has at least 27 moons, and 13 rings made from dust particles. They are very hard to see. One day on Uranus lasts for 17 hours. Uranus is so far away from the Sun that it takes 84 years to complete an orbit.

Uranus’ moons are named after characters in old books. Here are the names of four of Uranus’ biggest moons: Titania, Oberon, Ariel, and Umbriel.

Have you ever wondered why Uranus’ rings look like they are going up and down instead of side to side? Scientists think that, a very long time ago, a large object crashed into Uranus. This made it tilt onto its side, along with its rings.

Fun facts

It would take about eight years for a spacecraft to travel to Uranus from Earth.

If the Sun were as tall as a typical front door, Uranus would be about as big as a baseball.

Neptune

Neptune is the 8th planet from the Sun. It has at least 13 moons, possibly 14. It has several hard-to-see rings made from unknown particles. It takes 165 years for Neptune to orbit the Sun. This means that its winter lasts about 40 years.

Neptune has very powerful winds. They blow at 1,000 miles an hour (1,609 km/h). Storms on Neptune can last for a very long time, and they are much, much stronger than storms on Earth. One of these storms is called “The Great Dark Spot”.

Neptune’s largest moon is called Triton. Triton’s surface looks like a cantaloupe. It has many volcanoes which explode a mix of gas and dust. Triton is one of the coldest places in the Solar System, so when a volcano erupts, the gas and dust instantly freeze, and falls to the surface like snow.

Fun facts

A spacecraft travelling to Neptune from Earth would have nowhere to land since Neptune is a gas planet and has no surface.

If you enjoyed this post, I'll be writing another post about the Sun soon. Watch out for it!