Planets
Mars
The Red Planet, fourth from the Sun
About Mars
Mars is known as the Red Planet due to its reddish appearance caused by iron oxide on its surface. It has the tallest volcano in the Solar System, Olympus Mons.
Scientific Facts
Mars has a diameter of 6,779 km. Its day length is 24.6 hours. Surface gravity is 38% of Earth's.
Interesting Facts
Mars has two moons: Phobos and Deimos. A Martian year is 687 Earth days. The largest dust storms in the Solar System occur on Mars.
Fun Facts
Mars has the largest canyon in the Solar System (Valles Marineris). Footprints on Mars would take thousands of years to fade.
Discovery
Known to ancients; first observed through telescope by Galileo in 1610.