Mars 101:
The facts and the fiction

Despite its warm, reddish color, Mars is a very cold place. The temperature rarely rises above freezing and can go as low as -225 degrees Fahrenheit. Even on the warmest days, it only occasionally climbs to zero degrees Fahrenheit (-18 degrees Celsius) and from day to night it can drop as much as 212 degrees Fahrenheit (100 degrees Celsius).

Like Earth, Mars has seasons, due to the tilt of its axis in relation to the Sun. Images taken this year by the Hubble Space Telescope showed that the change of seasons is sweeping and violent: A long frozen winter gives way to a "summer" featuring pink dust storms, with winds up to 300 miles per hour, spawned when the planet's elliptical orbit brings it closest to the sun.

The Martian atmosphere is 96.5 percent carbon dioxide with only small amounts of oxygen. Nitrogen, carbon monoxide, argon, neon, and krypton are also present.

In 1877, Italian astronomer Giovanni Schiaparelli discovered apparent lines in the Martian surface. He called them "channels," but when his discovery was translated into English, it became "canals." Unfortunately this led some over-enthusiastic astronomers to speculate about the existence of life there. American astronomer Percival Lowell championed the belief that the "canals" carried melted water from the polar ice caps to irrigate crops and bring water to the cities. By 1909, astronomers had shown that even the "channels" were illusionary, but the belief in intelligent life on Mars lingered.

In 1938, Orson Welles broadcast a radio play about a Martian invasion of New Jersey based on H.G. Wells' "The War of the Worlds." Many listeners thought it was real and panicked.

Today we know that if there were any little green men on Mars, they'd be dead.

The reddish soil takes its color from oxidized (rusted) iron. The sky is pink due to red dust in the air.

Water exists on Mars in the form of ice and vapor, but it's too cold for water to exist in liquid form.