Mars

• At about 1/3 the size of Earth, Mars is the second-smallest planet in the Solar System after Mercury.
• The planet's red colour is caused by iron oxide on its surface.
• The gravity on Mars is about 37% of Earth gravity, so you could jump nearly three times higher on Mars.
• It has a thin atmosphere (about 1% of Earth) that is composed mostly of carbon dioxide, and not breathable by humans.
• Mars is colder than Earth. The temperature can get as high as a nice day on Earth (30°C) in Summer near the equator, but most of the time it's well below 0°C (down to -175°C at the poles).
• A day on Mars is slightly longer than a day on Earth.
• Mars has a more elliptical (oval-shaped) orbit than most other planets in the Solar System. This make its seasons uneven lengths and more extreme.
• Mars has two moons (Phobos & Deimos) that may be captured asteroids. The innermost moon, Phobos, is being pulled towards the planet and will eventually get ripped apart by tidal forces. This will result in Mars having a ring system (a bit like Saturn's) that will last for millions of years.
• The diameter of Mars is about half that of Earth.
• Earth has three times the surface area of Mars but two-thirds of Earth is underwater, meaning that Earth and Mars have about the same area of dry landmass.
• Mars has the tallest volcano in the Solar System (Olympus Mons). It used to be known as the tallest mountain in the Solar System but in 2011 a mountain on the asteroid Vesta (in Rheasilvia Crater) was found to be about the same height.
• Mars has the worst dust storms in the Solar System. They can cover the entire planet and last for months at a time.
• On Mars the sky is red during the day and turns blue at sunset.
• Mars used to have flowing water on the surface.
• People have never been to Mars but we have sent lots of robots there to learn about it. In fact you can say that Mars is the only planet inhabited entirely by robots (as far as we know).
• Mars is the most likely planet that people will be able to travel to and live on in the foreseeable future.
• Pieces of Mars have been found on Earth. In the distant past, asteroids or comets hitting Mars would have blasted many tons of the planet into space. Eventually some pieces found their way to Earth and fell as meteorites. We know they're from Mars because every planet has a unique chemical "fingerprint".

See also:

• The moons of Mars
• Mars FAQ