What makes Mars look red?

On a clear night, a little reddish dot shines in the dark sky. That dot is Mars, a planet far, far away. Picture lying on the cool grass and looking up at it.

People call Mars the Red Planet. But why does Mars look red? Let's find out together.

Mars has no grass, no trees and no seas. Its ground is all rocks, stones and fine dust. Those rocks and that dust give Mars the color we see from far away.

Inside the rocks of Mars hide small bits of metal. It is the same kind of metal a nail is made from. This metal is the start of the red.

Think of an old nail left out in the rain. Air and water touch it, day after day, and slowly change it. What color do you think that old nail turns?

It turns orange and red! We call that crumbly coat rust, which means the red skin that grows on old metal. Air and water turn the metal into rust.

Long ago, water and air touched the rocks of Mars, day after day. So the bits of metal in those rocks turned into rust too. That is how the rocks of Mars got their red.

Rust is soft and crumbly. Over a long, long time, the rusty rocks broke apart into fine red dust. That dust now covers the ground of Mars.

Wind on Mars picks up the rusty dust and blows it around. The wind spreads it over flat ground, over hills and into big round holes. So most of Mars wears a red coat of dust.

Sunlight shines on Mars and bounces off all that rust. The rusty dust sends back a reddish light. That light travels all the way to your eyes, so the dot glows red.

Air and water turned the metal in the rocks of Mars into rust. That red rust dust covers Mars, so Mars looks red.

Far away, the wind blows the rusty dust over the quiet hills of Mars. And the little red dot glows on in the dark sky.