Much has been learned about the planet Mars since astronomers first began studying it with their telescopes. Some scientific findings proved to be factual, while others were found to be myths. Still, the work of early scientists was invaluable. It stimulated people's curiosity and served as the foundation for centuries of Martian exploration and fascinating discoveries.

Similarities with Earth

Throughout history, many people believed that Mars and Earth were twins. Both are terrestrial, or rocky, planets rather than gaseous. Both have atmospheres and surface features such as towering mountains, deep canyons, and valleys, as well as ice caps at both the northern and southern poles. Also, as Sir William Herschel discovered in the 1700s, both planets are tilted at similar angles: Earth at 23.45 degrees, and Mars at 25.19 degrees. Because of this tilt, certain areas of Mars and Earth are oriented toward the sun at...