Mars's year is 687 Earth days long, almost 2 Earth years! But Mars's day is only 24 hours and 37 minutes long, nearly the same as ours.
Mars's Atmosphere and Weather
Mars's atmosphere is made of carbon dioxide like Venus's, but instead of being hot it is very cold on Mars. There is hardly any water vapor or oxygen in Mars's atmosphere. Mars's temperatures are -190* to 80*F. Most of the time the temperature only goes up to 32*F though.
The atmosphere pressure is about 100 times less than here on Earth. If people ever go to Mars, we will have to wear spacesuits to protect ourselves from the low temperatures and pressure. Mars has some clouds made of mostly carbon dioxide and some water vapor.
Mars has a tilted axis of 24*, a little more than Earth's 23.5*. Mars also has seasons that are caused by the solar heat on the planet. When Mars is close to the Sun, it is winter in the north and summer in the south. When Mars is far from the sun, it is the other way around.
Evidence of water in Mars's past can be seen in many places. Examples are the ancient riverbeds that were shaped by water. There probably is water still on Mars in the ice state, or permafrost (a frozen mixture of soil and ice).
Mars has two moons, Phobos and Deimos. Both are small and irregular in shape. Some people believe that they were asteroids who got too close to Mars and are now orbiting it. Phobos is only 14 miles in diameter, Deimos is about half its size. Deimos is the smallest moon in our solar system.
A Dry Planet
Martian Moons
