Planet Facts: Lesson for Kids

Instructor: Jeremy Cook

Jeremy has been teaching in elementary education for 13 years and holds a master's degree in Education

They're big, they're round and they circle a giant ball of hot gas. Can you guess what they are? Planets are amazing places full of mystery and wonder. This lesson will teach you the basics of planets and even those in our own solar system.

What is a Planet?

What do you think of when you hear the word planet? I'll bet you think of Earth or Mars or maybe even Saturn or Jupiter. But did you know that a planet is just a celestial body that makes a circular or elliptical orbit around a star? That's what the definition of a planet is. Notice how I said star and not Sun. While the planets in our solar system orbit around the Sun, there are planets in other solar systems and other galaxies that orbit around their own stars. Just imagine that many of the billions of stars we can see at night have their own planets orbiting around them. That's pretty amazing.

Mars is the fourth planet in our solar system. It has a rocky surface

Planets usually come in two major categories; rocky planets and gas giants. Rocky planets have a rocky surface and can have varying types of atmospheres. Astronauts could walk on the surface of a rocky planet. Earth and Mars are both rocky planets. Gas giants are made of various condensed gases and don't have a hard rocky surface, so we would not be able to land and walk around on them. Jupiter and Saturn are example of gas giants.

Our Planets

Right in our own solar system we have eight planets and several dwarf planets. Dwarf planets resemble the shape of regular planets, but often have odd orbits and are very small. Pluto, which was once our ninth planet, is now called a dwarf planet. Our first four planets, Mercury, Venus Earth and Mars, are called the inner planets and have rocky surfaces.

The planets in our solar system

The last four planets in our solar system are gas giants with tiny cores and no rocky surface. Jupiter, Saturn, Uranus and Neptune are the outer planets. There are several other dwarf planets in the solar system and astronomers are finding new celestial bodies year after year.

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