Mars may have once supported life and could potentially support human life in the future. It is approximately 227 million kilometers from the Sun, giving it a surface temperature range of -18°F to +80°F. Mars has an atmosphere composed of carbon dioxide, argon, and other gases. Water is believed to have once flowed on the Martian surface, but evaporated due to the planet's high temperatures. One of Mars' moons is predicted to crash into Mars in the future.