Mars is the fourth planet from the sun and also the seventh largest in the solar system. The month “March” was derived from its name. Mars has been known and observed since the ancient times. It is many times called the Red Planet. It is believed that people associated Mars’ red color with bloodshed and war; thus giving the reason behind its name. People have been studying this planet for centuries and have always been intrigued by Earth’s closest celestial neighbor.
In 877, Mars’ moons Phobos and Deimos were discovered by Asaph Hall. It wasn’t until 1965 though, that the first close up photos were taken when NASA sent the Mariner 4 to visit the Red Planet. These photographs were the world’s first pictures taken of a planet besides Earth. It wasn’t long after that, in 1976, that NASA sent space crafts to actually land on Mars. They sent two, the Viking 1 and 2. Next, in 1977, the first wheeled rover explored it. Many observations were made and valuable information was discovered, which only increased scientists’ curiosity about Mars and its past. Visits and studies starting in 2002 have been dedicated to analyzing the frozen water found on Mars. Strong evidence was found by the Mars Expedition Rovers that there was once liquid on its surface that probably formed the canals and canyons that have been observed. Many other studies and explorations have also been performed to determine its characteristics, interactions with the rest of the solar system, and possible life on the Red Planet.
Of the nine planets in the solar system, Mars is the seventh largest with a mass of 6.421x1023 kilograms, an average density of 3.95 gm/cm3, and an equatorial radius of 3,393 kilometers. “If the sun were as tall as a typical front door, Earth would be the size of a nickel, and Mars would be about as big as an aspirin tablet.” (http://solarsystem.nasa.gov/planets/proile.cfm?Object=mars) It is only slightly smaller than Earth; its surface area is almost equal to Earth’s dry land surface area. Its surface gravity is also smaller. Mars has a surface gravity of 3.72 m/sec2 with a pull of only 38% of Earth’s gravity. This means that if a person weighed 100 pounds on Earth, he or she would only weigh 38 pounds on Mars. It has a rotational period of 24.62 hours, longer than Earth’s rotational period.
Mars has two moons, Phobos and Deimos, named for the sons of the Greek god Ares. Phobos means panic or fear, which is also where the work “phobia” comes from. Deimos means flight, to run away. They are both very small compared to Earth’s moon and are two of the smallest moons in the solar system. They were also not formed in the same way. Most likely, they are fragments of larger space objects that have been broken apart. This accounts for their irregular shape and cratered surface. Phobos is about 27 kilometers long and only orbits 3,000 miles above Mars' surface. It makes one orbit in a little over seven hours and about three orbits...