Mars Is Red Because Its Surface Is Rusty

The nickname Red Planet is literal. NASA explains that Mars is frequently called the Red Planet because iron minerals in the Martian dirt oxidize, or rust, causing the surface to look red. People noticed the color long before anyone knew the cause. NASA notes that the Egyptians called the planet Her Desher, meaning the red one. NASA’s page gives a few other details about the planet. Mars completes one rotation every 24.6 hours, very close to a day on Earth, and Martian days are called sols. A year on Mars lasts 687 Earth days. Mars also has two small moons, Phobos and Deimos, that may be captured asteroids. It is the only planet where rovers have been sent to roam the landscape.