Mars, the fourth planet from the sun, has interested people for thousands of years, according to BBC News. However, whereas the people of ancient Greece and Rome found Mars fascinating for its red color, people today are more interested in finding water on the planet.
Mars is red because of the iron oxide, commonly called rust, that according to NASA makes up between 5 and 14 percent of the planet's soil. Yet Mars' red color was once believed by many ancient peoples to be because the planet was covered in blood. For this reason, the planet is named after the Roman god of war, Mars. The Greeks also named the planet after their god of war, Ares, and the Babylonians called it Nergal, which means "Star of death."
Scientists believe that water used to flow on Mars because of its canyons. In fact, Mars' Noctis Labyrinthus, meaning "labyrinth of the night," is the largest system of canyons in the solar system. The current atmosphere on Mars, which is mostly composed of carbon dioxide, prevents the existence of liquid water. Water can exist as ice or vapor on the planet, and scientists still believe that Mars might contain liquid water.
Another interesting fact about Mars is the way it influenced the Renaissance debate about the position of Earth in the solar system. While it was commonly believed in that time that Earth was the center of the universe, Nicholas Copernicus argued that Earth must orbit the sun because it overtakes Mars during its orbit, causing Mars to appear to move backwards in the sky.