Mars, the Red Planet
From Earth, Mars looks like a red dot in the sky, even without a telescope. Mars was named after the Roman god of war, maybe because it is red like blood. When astronomers looked at Mars through a telescope, they saw dark lines. In 1877, Italian astronomer Giovanni Schiaparelli made a map of these dark lines. He called them “canali.” This is a word for a natural path made by water, but some people saw the word and thought he saw canals. Canals are made by people. Some people thought that if there were canals on Mars, there must be life. We don’t know how these features formed. Maybe it was by water, but there is no water on Mars now except a little bit frozen at the poles.
Mars is the fourth planet from the sun. It is a little smaller than Earth but takes about as much time to rotate on its axis as Earth. This means that one day on Mars is about the same as one day on Earth. It takes Mars about two years to go around the sun.
In 1609, Johannes Kepler studied Mars and thought it moved in a strange way across the sky. Others of this time thought planets went in a perfect circle around the sun. He proved that Mars does not travel this way. In fact, all the planets travel in an elliptical pattern, but Mars’ orbit is more elliptical than most.

The view from Spirit's hazard avoidance camera sent back February 24, 2009. Image courtesy http://nasa.gov
Because Mars is relatively close and has a thin atmosphere, it has been heavily studied both from Earth and from space. It currently has three satellites orbiting and studying the planet, the most of any planet other than Earth. Its surface has many landers from various missions, some working and some out of service. Spirit and Opportunity, twin rovers on opposite sides of the planet, are currently sending information about the Martian surface back to scientists.



