Mars is called the red planet because it looks like a bright reddish light in the nighttime sky.
The red color comes from the presence of 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. A variety of unmanned spacecraft have been launched to visit Mars. Some spacecraft loop around the planet and study it from orbit, others have made treacherous landings, and some have crashed trying to land.
Visiting spacecraft show us that Mars is a cold, dusty, and barren planet. It has a very thin atmosphere—made up mostly of carbon dioxide—that is not breathable by humans. Because Mars is about one and a half times as far from the Sun as Earth, it is also much colder. A really hot summer day would be only about 70°F. Winter temperatures plunge to nearly 200 degrees below the freezing point of water (32°F).
