Study Map

The Solar System

Outer space is an amazing place, and it's pretty cool knowing that you're a part of it. Earth is a planet in what's known as a solar system. From where you live on Earth, you can see parts of the solar system when you look up at the sky, especially at night. You can see even more if your parents have a telescope that you can look through. The moon, stars, and sun are all parts of the solar system. But do you know exactly what a solar system is?

The sun that keeps you warm is actually a star. The sun and everything that orbits or travels around it make up the solar system. Planets like Earth are moving very fast around the sun. The moon, meteoroids, and comets also travel around the sun. This solar system is billions of years old, and it isn't the only one out there. In fact, it's just one of the billions in the Milky Way galaxy!

The sun is huge, and because it's so big, it has a lot of gravity. What is gravity? Gravity is a force that pulls things together. On Earth, gravity is what keeps you from floating away. The sun's gravity is so strong that it pulls planets toward it. That's pretty scary when you think about how hot the sun is! The good thing is that planets like Earth are also trying to pull away from the sun. It's like a tug of war! Because they're being pulled in two directions, planets don't get too close or too far away from the sun.

There are eight major planets in our solar system. The four largest are Jupiter, Saturn, Neptune, and Uranus. These planets are called gas planets because they're mostly made of gases. The four planets closest to the sun are called terrestrial planets, and instead of gas, they have surfaces made of dirt and rock. These planets are Mercury, Venus, Earth, and Mars. Most of the planets have at least one moon. Jupiter has more than 50! Other planet-like objects in the solar system are the dwarf planets, which include Pluto, Eris, Ceres, Makemake, and Haumea.

Asteroids are also objects in the solar system. There are thousands and thousands of asteroids, which are rocky objects that aren't the shape or size of planets. They are typically much too small to be considered planets. Most of them are in the asteroid belt between Jupiter and Mars. There are also asteroids in other parts of space, and some even come close to Earth! Other small objects in the solar system are comets and meteoroids. Comets are small chunks of frozen gas, dust, and rock. A meteoroid is a chunk of rock or debris. If it enters Earth's atmosphere, it's called a meteor. Have you seen a picture of a meteor that has a bright tail or trail? That happens because it heats up when it enters the planet's atmosphere. If a piece of it hits the ground, that's called a meteorite.