A long time ago, Tom asked me this question. I gave Tom an answer in class, but now I’m getting around to writing about it. Remember, when people talk about space, planets, and stars, we need to use a lot of guesses. Let’s go get red!
Mars is a planet in our solar system. There are 8 planets going around the sun and Mars is the fourth one, right after Earth. The core of our planet, Earth, is made of a metal called iron (I – ern). Core means the ball in the very middle of a planet. Sometimes, this metal is found on top of the Earth too. Many things like bicycles, cars, buildings, and ships are made of iron. Just like Earth, Mars has a core made of iron too.
When iron touches oxygen (ox – i – jen), it starts to change. It turns into a thing called iron oxide. (ock – side) The easy, normal name we use for iron oxide is rust. There is oxygen in the air and water. After iron starts to rust, it will change from dark gray to red or orange. So now we know that Mars looks red because it is covered in rust. But why is there so much rust on Mars?
The rust on Mars is actually just a very thin layer on top. In most places, the rust is only about 1 cm thick. The wind on Mars blows this rust dust around the whole planet. Volcanoes on Mars are much bigger than volcanoes on Earth. Some astronomers think that these huge volcanoes pulled a lot of iron from the core and blow it out onto the top of Mars. Then, the iron changed into rust to give Mars the red color. Some astronomers think Mars had water on it a long time ago, and maybe air, so the iron changed to rust with the oxygen in the water or air.