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Mars Geology:

So Familiar, Yet So Different!

Mars, also known as the Red Planet has many of the same characteristics as Earth. Many features of Mars, though, are entirely exclusive to that planet. It has taken numerous years for humans to begin to understand about Mars and its history. In the near future with the help of advancing technology and space travel, we hope to find out more about Mars than we’ve ever thought possible. There are many interesting facts, both simple and complex, that have fascinated me throughout this project.

Mars, the fourth planet from the sun, has a diameter of 6,790 kilometers which is a little more than half the size of Earth. Even though Mars is much smaller, the surface area is equal to the total land area on Earth, due to the fact that 70% of Earth’s surface is covered by liquid water. Unlike the Earth, Mars currently has absolutely no liquid water on its surface and is covered by bare rocks and dust. Physical features on the planet, however, suggests that great rivers and possibly seas once existed. Perhaps the Martian atmosphere once was thicker and could sustain water on its surface forming the polar ice caps, which continue to grow and recede with the seasons. In the distant past running water made the Martian climate wet and warm. Now the majority of the planet is a cold, dry desert. What events would have caused such drastic changes to this planet’s environment?

Mars also has many other land features such as huge canyons, massive volcanoes, polar ice caps and vast lands of sand dunes. The huge canyons, which are 5 times as deep and 10 times as long as the Grand Canyon, show evidence of marsquakes and landslides. Massive volcanoes rise from the surface to heights greater than twice the height of Mount Everest. Three of these volcanoes are visible to the west as dark red spots. Craters of all sizes cover the land, making Mars look similar to the Arizona desert. The dust storms on Mars can develop and build up so enormously that they cover the entire planet. Most of the time the skies are the color of butterscotch while the sunsets and sunrises bring pink and red skies along with a blue tinted sun. Having learned from physics that this only happens when there are small amounts of nitrogen in the atmosphere, Earth would rarely ever see these spectacular conditions.

In 1976 the Viking 1 orbiter photographed a mountain which appeared to be a wind-sculpted mesa resembling a human face. The face-like appearance might have been due to the lighting conditions at the time the photographs were taken. Writers have popularized the idea that the “face” was carved by intelligent beings. The odds are high that of all the millions of features photographed on Mars, one would resemble a face. But humans have the tendency to recognize patterns that are familiar to them. The same thing happens to us when we look at the clouds here on Earth.

Data collected from spacecrafts suggests the interior of Mars is made of a thin crust, a mantle, and a core, similar to Earth’s. The core is believed to be composed of iron or maybe even less dense materials, such as a mixture of sulfur and iron. Mars, with clouds, fog, storms, and river beds, is a familiar yet altogether different world. It is the similarities that intrigues us all, or is it the differences?

In 1877, the astronomer Asaph Hall discovered the moons of Mars. He named then Phobos and Deimos after the sons of Ares, the god of war in Greek mythology. Phobos, Greek for fear and Deimos, which means panic, both served as Ares’ chariot attendants. The moons’ origin is based on a theory that they are captured asteroids. Phobos, like most small bodies in the solar system, is irregular in shape and measures 27 kilometers by 19 kilometers. Phobos orbits Mars once every 7 hours, giving observers on Mars two chances to see it in one day. Phobos’ orbit is 6,000 kilometers(3,750 miles) above the surface. Mars is slowly pulling Phobos inward and the rate is gradually increasing. In about 40 million years Phobos will either crash into Mars or be torn into pieces, which would continue to orbit as a ring of debris around Mars. Deimos is the smaller of the Mars’ moons but is further away from the planet’s surface than Phobos. Deimos measures 15 kilometers by 11 kilometers. The surface of Deimos is smoother than Phobos due to a thicker layer of debris, called regolith. Deimos moves much slower than Phobos, orbiting Mars once every 30 hours. Phobos and Deimos are also thought to be similar to carbonaceous asteroids and contain up to 20% water in their minerals, which makes this a potential water hold for future space travelers. These moons could now possibly be Mars’ most important resources.

Mars is very similar to the Earth in its rotation rate and tilt of its axis. Both also have similar daily and seasonal changes. However, the atmosphere on Mars is composed of primarily of carbon dioxide with small amounts of other gases. Compared to the breathable air on Earth, with only .03% CO₂, Mars has over 90% more carbon dioxide in its thin atmosphere. The atmospheric pressure is estimated at about 1/150^th that of the Earth. Even though Martian air contains only 1/1000^th as much water as our air, the small amount of water still condenses to from clouds. Even local patches of early morning fog can form in valleys and a thin layer of frost has also been seen at the Viking Lander 2 site covering the ground each winter morning. The average temperature of Mars is about -67° F, while the surface temperatures range from -207° F at the winter pole to 80° F on only the dayside during the summer. It would be very difficult to sustain life on Mars due to the extreme temperature ranges on the surface.

The idea of life on Mars has been lingering in people’s imaginations since the late 1800s, when Percival Lowell came up with the theory that an alien civilization built series of “canals” on Mars. Up until the 1960's it was widely thought that seasonal changes seen on Mars might be due to plant life. But in 1976, Viking orbiters 1 and 2 mapped the Martian surface and revealed that the valley networks and flood channels were overlaid with impact craters. In 1971, the Mariner 9 spacecraft made the first global map of Mars and discovered the northern hemisphere had a very Earth like surface. The Mariner 9 also proved that intelligent life did not exist on Mars and that Lowell’s “canals” never existed. Scientists had to assume that even if there was life on Mars in the past, it should have left some organic residues in the soil. Specific searches on the surface for chemical evidence resulted both negative and inclusive.

Mars is a very interesting planet, even though it’s very similar to Earth, humans have a lot

more to learn about the “Red Planet”. I believe someday soon we will be able to travel to Mars and learn more about it. In my opinion, Mars has the potential to be the next logical destination for space travel.

The Volume Library Southwestern / Great American, Inc., Volume 1, pages 342-343 1998

Final Project