MarsMars is the fourth planet from the sun and the last of the solid, non-gaseous planets in our solar system. Mars is the seventh largest planet in our solar system. The diameter is approximately 4,220 miles. The equatorial circumference is approximately 13,259 miles. Earth's equatorial circumference is about 24,901 miles, so Mars' equatorial circumference is about 53.2% of Earth's. The radius of Mars' core is 1,056 miles. The area is 55,742,106 square miles, or about 28% of Earth's area. The volume of Mars is 163,115,609,799 cubic kilometers. The mass is approximately 641,693,000,000,000,000,000,000 kilograms. The average density of Mars is 3,933 kilograms/meter3. The average density gives clues about the planet's composition, such as how much metal it contains and whether the planet is solid or gas (Mars Facts). Mars is made up of many different materials. The crust and surface are primarily iron-rich basalt rock, similar to the thin crust of the Earth. The mantle consists of silicate rock and the core is probably a core of iron, nickel and sulfur. However, scientists are unsure whether the core is a hot liquid or a cooled metal and whether or not it has two distinct layers like Earth's. The composition of Mars is similar to that of Earth. The main gases that make up Mars' atmosphere are carbon dioxide (CO2), argon (Ar), nitrogen (N2), oxygen (O2), and carbon monoxide (CO). There is approximately 96% carbon dioxide, 1.93% argon, 1.89% nitrogen, 0.145% oxygen and less than 0.01% carbon monoxide. The atmosphere of Mars also contains other gases in very small quantities, called trace gases. Mars' atmosphere is about 100 times less dense than Earth's (Mars Facts). The temperature on Mars is colder than on Earth because it is further from the sun. Middle of paper ......temperatures and climates on Mars, the possibility of humans reaching the planet and surviving, are realistic according to scientists. Mars One, a community of scientists who believe in this reality, has already started collecting applications for those who want to take a one-way trip to Mars. They plan to start making these trips in 2024 (Human settlement on Mars). It may not seem realistic to be able to start a human colony on Mars in just ten years, but it is possible. Mars One. Mars One, and Web. May 9, 2014. “Mars Exploration. » National Geographic. National Geographic, nd Web. May 7, 2014. “Mars Facts.” » Mars Facts-Mars Exploration Program. NASA, nd Web. May 1, 2014 "Mars: Moons." Exploration of the solar system. NASA, nd Web. May 11, 2014. “The Moons of Mars”. The Moons of Mars. Np, and Web. May 7 2014.