- Mars is the 4th planet from the Sun and last of the terrestrial planets.
- Mars is named after the Roman god of war.
- A common nickname for Mars is "The Red Planet."
- Many people once believed Mars to possess intelligent life. This belief resulted from the discovery of lines that appeared to be too straight to occur naturally. It was later discovered, however, that the lines weren't as straight as previously believed, and thus it was realized that there was no proof for intelligent life on Mars.
- Of all the planets other than Earth, Mars is the most hospitable to life.
- Martians, or extraterrestrials from Mars, are a common character in science fiction books and movies.
It takes Mars 687 (Earth) days to orbit the sun.
Mars in the only planet, other than the Earth, that has polar ice caps. They are called Planum Boreum (northern cap) and Planum Australe (southern cap).
Mars is tilted on its axis by about 25.19 degrees, which is similar to the axial tilt of the Earth (22.5 degrees). This means that Mars has seasons like the Earth, although they last nearly twice as long.
Mars has the second most eccentric orbit out of all the planets in the Solar System, which means that its orbit is the second least like a circle.
In the book 'Gulliver's Travels', the author Jonathon Swift wrote about two moons of Mars, about 150 years before they were discovered.
Mars has no magnetic field, although some scientists believe that Mars did have a magnetic field about 4 billion years ago.
Water ice has been found under the surface of Mars, mostly below the polar caps.