Mars - Named After a Roman God of War from Ancient Times

One of Earths next door neighbors in the solar system is Mars. Mars was named after a Roman god of War from ancient times. (Squyres, 1) Mars has many questions and possibilities due to it's complex environment. Is or was there ever life on the planet? Many different observations from Earth and from spacecraft have been performed to try to understand this 4.6 billion year old planet. (Squyres, 1)

Mars is the farthest terrestrial planet from the Sun and orbits between Earth and the asteroid belt. Many of studies on Mars have shown some characteristics to be similar and different between Mars and Earth. In 1666, J.D Cassini was the first person to identify the rotational period of Mars. (Life on Mars, 1) Cassini observed Mars by a refractor having small object glasses and long focal lengths for high magnification over a series of nights and had noted that the planet rotates slightly slower than Earth. He was able to accurately calculate the rotational period as twenty-four hours and forty minutes. (Harland, 3) Cassini was right in that Mars orbit is slightly more stretched out than Earth and most of the other planets. Since Mars has an elliptical orbit, at different oppositions Mars is at a different distance from Earth and the closer Mars is to us, the larger it can appear. "The distance from Mars to the Sun can be as little as about 128,390,000 miles (206,620,000 kilometers) or as much as about 154,860,000 miles (249,230,000 kilometers)" (Squyres,2). The length of the Martian year is 687 Earth days by calculating how many days it takes Mars to travel once around the Sun. (Squyres,2) Mars has a mass of 7.08X 1020 tons about ten times less mass than Earth. (Squyres,

2) The density of mars is very low when comparing it to Earth's density, at only one percent the density of Earth's.(Arny, 254) In the textbook "Explorations: An Introduction to Astronomy" it described Mars density to be "so low that, although the Martian atmosphere is mostly carbon dioxide, it creates only a very weak greenhouse effect" (Arny, 254). An interesting characteristic of Mars is the gravitational force. Since Mars is smaller and less dense than Earth it makes the force of gravity only thirty-eight percent of that on Earth. (Squyres, 2) On the NASA website it described the gravitational force on mars to " a person standing on Mars would feel as if his or her weight had decreased by sixty-two percent. And if that person dropped a rock, the rock would fall to the surface more slowly than the same rock would fall to Earth" (Squyres, 2).

The physical features of Mars include a crust, mantle and core. Most of the northern hemisphere of Mars has a lower elevation which makes the crust thinner than in Mar's southern hemisphere. The average thickness of Martian crust is 30 miles. (Squyres, 2) In the text, Astronomers believe "Mars has cooled and its crust thickened to perhaps twice the thickness

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