The Eight Planets
Name the eight planets in order from the Sun (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune), know that Pluto is a dwarf planet, and distinguish rocky inner planets from gas giant outer planets
What a learner can do afterwards
- List all eight planets in order from the Sun
- State that Pluto was reclassified as a dwarf planet in 2006
- Explain that the four inner planets are small and rocky while the four outer planets are large gas giants
1 · Read
Eight planets circle the Sun. Each one follows its own path, called an orbit. The planets closer to the Sun move faster and get more heat and light.
A memory trick can help: My Very Eager Mother Just Served Us Nachos. The first letter of each word matches the first letter of a planet, in order.
For a long time, people counted Pluto as the ninth planet. In 2006, scientists set clearer rules for what counts as a planet, and Pluto did not fit them. Now Pluto is called a dwarf planet.
The four planets closest to the Sun, Mercury, Venus, Earth, and Mars, are small and made of rock. The four planets farther out, Jupiter, Saturn, Uranus, and Neptune, are huge balls of gas called gas giants.
Eight planets orbit the Sun in order, four small rocky ones close in and four giant gas ones farther out, and Pluto is now a dwarf planet, not a full planet.
More to read
Key points: The solar system
Our solar system is like a big family with the Sun as the parent. About 4.6 billion years ago, a giant cloud of gas and dust collapsed and started spinning. Most of the stuff fell into the middle and became the Sun. The leftovers formed the eight planets, moons, asteroids, and comets. The four planets closest to the Sun (Mercury, Venus, Earth, Mars) are called the inner planets. They are small, rocky, and have few or no moons. The four outer planets (Jupiter, Saturn, Uranus, Neptune) are huge gas giants with thick atmospheres, many moons, and rings.
How Was Our Solar System Formed?
Imagine a giant spinning pizza made of gas and dust. That is how our solar system began! Gravity pulled the material tighter and tighter until the center got so hot it ignited as the Sun. The planets formed from the leftovers. Rocky planets grew close to the Sun where it was too hot for gas to stick around. Farther out, where it is cold, giant planets swept up gas and ice. That is why we have small rocky worlds inside and big gassy ones outside.
Features of Planets
Each planet has its own personality. Mercury zips around the Sun in just 88 days and has wild temperature swings. Venus spins backwards and traps heat under thick clouds. Earth is the only one we know with liquid water and life. Mars has the tallest volcano and a canyon as wide as the United States. Jupiter is so big all the other planets could fit inside it. Saturn floats on water if you had a bathtub big enough. Uranus rolls on its side like a barrel. Neptune has the fastest winds in the solar system.
Explore more
2 · Watch
به انگلیسیTake it off screen
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.