Learn about the Inner Planets — Passage and Quiz

Our solar system is an amazing place filled with planets, moons, asteroids, and more. Today, we're going to learn about the inner planets. These are the planets closest to the Sun, and they're also called the rocky planets because they're made mostly of rock and metal.

There are four inner planets: Mercury, Venus, Earth, and Mars. Mercury is the smallest and closest to the Sun. It's very hot during the day and very cold at night because it doesn't have much of an atmosphere to keep it warm. Venus is often called Earth's twin because it's about the same size as our planet, but it's much hotter - even hotter than Mercury! This is because Venus has a thick atmosphere that traps heat.

Earth is our home planet. It's the only planet we know of that has life. Earth has everything we need to survive: water, air, and the right temperature. Mars is often called the Red Planet because of its reddish color. It has mountains, valleys, and even ice caps at its poles.

The inner planets are different from the outer planets in many ways. They're smaller and denser, meaning they're packed tightly with heavy materials like rock and metal. They also have few or no moons. Mercury and Venus have no moons, Earth has one moon, and Mars has two small moons.

These planets formed closer to the Sun, where it was too hot for gases like hydrogen and helium to stick around. That's why they're made mostly of heavier materials. The inner planets also have solid surfaces that you could walk on (if you had a spacesuit, of course!).

Learning about the inner planets helps us understand our place in the solar system. Each of these worlds is unique and fascinating, and scientists are always discovering new things about them. Who knows? Maybe one day, humans will visit these other rocky worlds and learn even more!