11 Amazing Planet Facts for Kids

Our solar system is full of surprises. On one planet the Sun rises in the west, a year on another lasts 84 Earth years, and the biggest planet could hold more than 1,300 Earths. These 11 amazing planet facts for kids are easy to read aloud, remember, and share the next time you look up at the night sky.

In our home, trips through space often begin curled up together on the sofa. Our son has declared Saturn his favorite planet, naturally because of those enormous, glowing rings. Whenever he picks up our planet book, he usually turns to Saturn first and then checks which world is coldest, biggest, or fastest. Even though he knows many pictures in our book “Planet Book for Kids: We Are the Planets” by heart, he loves looking through it again and again.

1. There are eight planets in our solar system

The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. They all travel around the Sun. Pluto was once called the ninth planet, but it has been classed as a dwarf planet since 2006.

2. Mercury is the smallest planet

Mercury is both the smallest planet and the closest one to the Sun. Its surface becomes extremely hot during the day and bitterly cold at night. Mercury has almost no protective atmosphere, so it cannot hold on to heat.

3. The Sun rises in the west on Venus

Venus spins in the opposite direction from most planets. The Sun would rise in the west and set in the east. Venus is also the hottest planet because its thick atmosphere traps heat like an enormous blanket.

4. Earth is the only known planet with life

Earth sits at a distance where liquid water can exist. Water, a protective atmosphere, and suitable temperatures create conditions where plants, animals, and people can live. Earth races around the Sun at roughly 67,000 miles per hour (107,000 km/h).

5. Mars has the largest volcano in the solar system

Mars is called the Red Planet because its soil contains lots of iron that has rusted. It is home to Olympus Mons, the largest known volcano in the solar system. The volcano is more than twice as tall as Mount Everest.

6. More than 1,300 Earths could fit inside Jupiter

Jupiter is the biggest planet in our solar system. By volume, more than 1,300 Earths could fit inside it. Its famous Great Red Spot is an enormous storm that has been swirling for a very long time.

7. Jupiter's moon Ganymede is bigger than Mercury

Jupiter has more than 100 known moons. The largest is Ganymede, and it is even bigger than Mercury. It is still a moon because it travels around Jupiter rather than orbiting the Sun directly.

8. Saturn could theoretically float on water

Saturn is made mostly of gas and has a lower average density than water. In an impossibly enormous ocean, it would theoretically float. Its famous rings are made from countless pieces of ice, rock, and dust.

9. A year on Uranus lasts 84 Earth years

Uranus is so far from the Sun that it takes 84 Earth years to complete a single orbit. Uranus is tilted almost completely on its side and seems to roll around the Sun.

10. Neptune has the strongest planetary winds

Neptune is the outermost of the eight planets. Winds in its atmosphere can blow faster than 1,200 miles per hour (2,000 km/h). Before astronomers spotted Neptune through a telescope, mathematicians had already predicted where it should be.

11. Pluto is now a dwarf planet

Pluto was described as the ninth planet for many years. Since 2006, it has officially been a dwarf planet because it has not cleared other objects from the area around its orbit. Pluto has mountains made of water ice, a thin atmosphere, and five known moons.

Quick planet facts to remember

• Our solar system has eight planets.
• Mercury is the smallest planet, while Jupiter is the largest.
• Venus spins in the opposite direction from most planets.
• The largest volcano in the solar system is on Mars.
• Saturn could theoretically float because of its low average density.
• Neptune has the strongest winds of any planet.

Frequently asked questions about planets for kids

Which planet is closest to the Sun?
Mercury is the closest planet to the Sun. Venus is hotter on average because its thick atmosphere is extremely good at trapping heat.

Which is the biggest planet?
Jupiter is the biggest planet in our solar system. Its diameter is about eleven times wider than Earth's.

Which planet has the clearest rings?
All four outer giant planets have rings, but Saturn's bright ring system is by far the easiest to see from Earth.

Discover more space facts in “We Are the Planets”

All eight planets, the Sun, Pluto, asteroids, and a comet introduce themselves in our lovingly illustrated children's book “We Are the Planets”. Short explanations and extra “Did you know?” facts make the solar system approachable for children ages 4 to 8. A quiz with answers and an activity page let young readers use what they have learned right away.

Take a closer look at the planet book

Which planet fact amazed your child the most, and which planet is their favorite? Tell us in the comments!