Free
Mars is called the red planet.
That’s because it looks like a bright reddish light in the sky at night. The red color comes from the minerals iron oxide and olivine on its surface. Some astronomers once thought that Mars might have intelligent life. Science fiction writers were inspired to write stories about invaders from Mars, or Martians.
In reality, Earth is “invading” Mars. We have sent different unmanned spacecraft to visit it. Some of them loop around the planet and study it from orbit. Others have made dangerous landings, and some have crashed into the surface while trying to land.
Visiting spacecraft show us that Mars is a cold, dusty, and bare planet. It has a very thin atmosphere that humans can’t breathe, made up mostly of carbon dioxide. It’s about one and a half times as far from the Sun as Earth. That means it’s much colder than Earth. A really hot summer day would be only about 70°F. Winter temperatures drop to nearly 200 degrees below the freezing point of water (32°F).
