Rust in the soil creates the Red Planet's signature color.
Size: Mars is about 4,212 miles (6,779 kilometers) in diameter.
Distance from the Sun: Mars is the fourth planet from the Sun and orbits roughly 142 million miles (229 million km) away.
Orbit around the Sun: It takes 687 Earth days for the Red Planet to go around the Sun one time.
Rotation: Mars spins on its axis at about the same speed as Earth does. It takes 24 hours and 37 minutes (about 1 Earth day) for Mars to rotate one time.
Surface: There are lots of dry channels on Mars, and they look like Earth's river channels. Most scientists believe water once flowed on the martian surface, but new studies suggest there still may be water in some places at and under the surface.
Mars has the largest canyon (Valles Marineris), and the highest volcano (Olympus Mons) in the solar system.
If Valles Marineris were on Earth, it would span the United States, from New York on the East Coast to California on the West Coast. The canyon is about 1,300 miles (2,100 km) long, 300 miles (500 km) wide, and about 5 miles (8 km) deep.
Olympus Mons is about three times higher than Mount Everest. It rises above the Martian surface 14 miles (22 km). This giant volcano's base is the size of the state of Missouri.
The planet's reddish color is caused by rust (iron oxide) in the soil.
The polar ice caps on Mars are made of frozen carbon dioxide, or dry ice, plus a seasonal coating of water ice.
Atmosphere: The martian atmosphere is very thin and made of carbon dioxide (95 percent), nitrogen (3 percent), argon and other gases (1 percent).
Temperature: The lowest surface temperature on Mars is 190° F (123° C), while the hottest temperature is 90° F (32° C).
Escape velocity: To escape the gravity of Mars, you have to travel 11,200 miles (18,000 km) per hour, compared to 25,000 miles (40,200 km) per hour necessary to escape Earth's gravity.
Other information: Because the Red Planet's color reminded ancient astronomers of blood, they named the planet after their gods of war. Mars was the Roman god of war, while Ares was the Greek version.. The planet's two moons also have names that relate to war. Phobos means "fear," and Deimos means "panic." Phobos is about 17 miles (27 km) in diameter and Deimos is about 9 miles (14 km).