Mars is the fourth planet in order from the Sun and the second smallest planet in the Solar System, after Mercury. Named after the Roman god of war, it is often referred to as the "Red Planet" because the iron oxide prevalent on its surface gives it a reddish appearance.
Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys, deserts, and polar icecaps of Earth.
- The average surface temperature on Mars is a frigid -63°C (-81°F) compared with Earth's average of 14°C (57°F).
- The length of a Martian day is 24 hours 37 minutes.
- The length of a Martian year is significantly longer than Earth's at 687 days.
- The gravity on Mars' surface is 62% lower than it is on Earth. At just 0.38 of the Earth standard (3.7 vs 9.8 m/s^2), a person who has a mass of 100 kg (220 lbs.) on Earth would have the same 100-kg mass on Mars but the weight on earth of 980 N would only be 373 N on Mars.
- The diameter of Mars is 53% of Earth's, making it the second smallest planet in the solar system.
- The surface gravity of Mars is 38% that of Earth, so if you weigh 100 pounds on Earth, you would weigh only 38 pounds on Mars.
- A year on Mars is 687 days but a day on Mars is only 40 minutes longer than ad day on Earth.
- Mars has the largest mountain/volcano in the Solar System. Olympus Mons is a shield volcano, three times the height of Everest standing at nearly 22km with a 600 km diameter. It is almost the size of France and some scientists believe that it's still active.