Diameter: 4,194 miles or about half the diameter of Earth
Number of moons: 2
Length of year: 687 Earth days
Temperature: -266°F to -62°F
Mars is mainly made of rock, with a metallic core.
Mars is the fourth planet from the Sun, and is about half as big as
Earth. Mars is covered with red rocks, and has white ice caps at the
poles. There are huge volcanoes and lots of craters on the surface.
Some scientists think they may have found evidence that primitive life
forms existed on Mars long ago. There is no life known to exist on Mars
today.