Mars:

Landforms

Mars has many unique landforms. One of them is Olympus Mons, a volcano of extremely gigantic proportions. It’s almost 16 miles high! That’s nearly twice the height of Mount Everest! The base of the volcano would cover almost the entire state of Arizona! Mars also has three other large volcanoes, though they are smaller than Olympus Mons. They are Arsia Mons, Pavonis Mons, and Ascraeus Mons. These four volcanoes are no longer active. The area in which these volcanoes lie is called the Tharsis bulge.

Another interesting landform is Valles Marineris. It’s a very long valley extending 2,100 miles southeast starting at the Tharsis bulge. That’s about the distance between California and New York! One spot in the valley is 4 miles deep. That’s more than four times as deep as the Grand Canyon. Also, its widest point is 440 miles across. That's equivalent to the distance between Washington D.C. and Boston, Massachusetts.

Hellas Planitia is a very interesting landform. It is a gigantic basin, an area of low land surrounded by higher land, in the southern hemisphere. Hellas Planita is the largest basin on Mars at 1,250 miles across! That’s the distance from New York to Kansas. Hellas Planitia was probably formed when a giant meteorite hit the surface of Mars.

A final important landform on Mars, and maybe the most important, is its polar ice caps, located at its north and south poles. These are important because if we ever try to colonize Mars, we will need a source of water. These ice caps grow during the winter and shrink during the summer. This happens the same way that it happens on Earth. When it gets cold enough, carbon dioxide and water freeze. When it gets warm they melt.

There are several differences between the northern and southern ice caps. The northern ice cap is made up of water and is about 620 miles across before it gets larger because of the cold. The southern ice cap is about a third of the size of the northern ice cap, and it is made up of water and carbon dioxide. In winter, the southern ice cap grows to be bigger than the northern ice cap.

Atmosphere

Mars has an atmosphere that’s very thin compared to Earth’s. Mars’s atmosphere is 95% carbon dioxide, about 3% nitrogen, and about 2% argon. Also, there are traces of other gases such as oxygen, carbon monoxide, and water vapor. Earth’s atmosphere is quite different. It’s 78% nitrogen, 21% oxygen, .9% argon, and .3% carbon dioxide along with traces of other gases.

Mars has three different types of clouds: large pink clouds made up of dust, blue clouds which scientists think are made up of ice crystals, and white clouds which are thought to be made up of water vapor.

Interior

Few things are known about Mars’s interior because no probes with the right kind of instruments have ever been sent to Mars. Scientists do have several guesses about it, though. They think that Mars has a crust, mantle, and core just like Earth. The estimated range of sizes for the crust is anywhere from 9 miles to 80 miles thick. Scientists believe that the core is quite large and mostly made up of iron and nickel.

Exploring Mars

The United States has launched many probes to explore Mars. The first one to take pictures of Mars was Mariner 4, launched in 1963. Since this probe did not have any of the technologies we have today, all it found were craters. This led people to believe that Mars was a lot like Earth’s moon. Later, Mariner 6 and 7 were launched. These probes took more detailed pictures, studied the atmosphere, and studied Mars’s gravity. In 1971, Mariner 9 was launched. Mariner 9 found that there were volcanoes and canyons on Mars. This changed the belief that Mars is like the moon to Mars is like the Earth.

In 1975, two more probes were launched. They were Viking 1and 2. The Viking probes consisted of orbiters and landers. The orbiters mapped Mars while the landers studied the soil and searched for life. These landers were the first on Mars.

In 1992, Mars Observer was launched. Its mission was to study the planet’s land, climate, and magnetic field. Unfortunately, a few days from reaching Mars, NASA lost contact with it. To make up for the loss, a new probe was constructed out of the leftover parts from the Mars Observer. It was called Mars Global Surveyor 96. This mission could result in sending manned spacecraft to Mars in 2011.

Mars Pathfinder was also launched in 1996. Mars Pathfinder had two parts, a lander and a rover. The lander studied the weather, while the rover studied surface materials. The rover looked at 15 different rocks, and the lander sent back several pictures.

A final probe launched was the Mars Polar Lander. It was launched in January of 1999. Its mission was to study the soil, temperature, wind pressure, and humidity. While the lander was landing, two microprobes were going to slam into the ground and look for water and signs of life. Unfortunately, when it was starting to land NASA lost contact with it. Nobody knows what happened to it, and we might not ever know.

Life on Mars

Is there life on Mars? Many scientists say there isn’t, but other scientists say there is. One reason scientists think that there is no life on Mars is because of its extreme temperatures. Temperatures can go as low as –207 degrees F to as high as 80 degrees F. During most of the day, water would be frozen and hard to get. Because of this, no human would be able to live on Mars. However, this does not rule out life forms such as bacteria. Also, because of Mars’s thin atmosphere, harmful radiation from the sun could reach the planet’s surface. This could easily burn any known living thing on the planet.

However, even with the extreme temperatures, thin atmosphere, and harmful radiation there is still a chance that there could be life on Mars. There are many cracks in the rocks and on the planet’s surface. These cracks could offer protection from the extreme conditions on the planet’s surface. Also, it would be possible for water to exist under the surface because the temperature wouldn’t change as much. One important piece of evidence to support the idea that there is life on Mars was found in 1984 when a meteorite was found in Antarctica. This meteorite was later identified as being from Mars. The meteorite contained objects that could be fossils of tiny bacteria.

Moons

Mars has two moons. Their names are Phobos and Deimos. These are the names of Mars’ (the God’s) two sons. Mars’ moons were probably asteroids that got pulled into orbit around the planet by its gravity. Both moons were discovered by Asaph Hall in 1887. Phobos and Deimos are some of the smallest moons in our solar system. Phobos is 17 miles wide, and Deimos is 9 miles wide. They’re mostly made up of rock and ice. Phobos and Deimos have many craters on them.

Phobos has many interesting features. One of them is a huge crater called Stickney. The asteroid that made Phobos’ biggest crater was so big that it nearly destroyed the moon. The pressure from the asteroid hitting it was so strong that it almost shattered Phobos. The valleys and grooves on Phobos are believed to be an effect of the asteroid hitting it.

Phobos is in danger of being destroyed! Its orbit is only 3,600 miles from the surface while Luna, Earth’s moon, is 250,000 miles away from Earth. Phobos’ orbit is lowering by about 6 feet every 100 years because of the gravitational pull of Mars. At this rate, in about 40 million years, Phobos will either crash into the surface of Mars or break up and form a ring.

Interesting Facts

Links to Another Great Site on Mars

"Grand Canyon." Encarta, 2001.

Bill Arnett. The Nine Planets. <http://www.seds.org/nineplanets/nineplanets> Last Visited: January, 2002.

Elvia Thompson. NASA. <http://www.nasa.gov> Last Visited: December, 2001.

Last Visited: December 2001

Mars Gazette. <http://www.amnh.org/rose/mars/pl5.html> Last Visited January, 2002.

Mars News. <http://www.marsnews.com/focus/life> Last Visited January, 2002.

Pasachoff, Jay. Science Explorer Astronomy Needham: Prentice Hall, 2000.

Robert Nemiroff, Jerry Bonnell. Astronomy Picture of the Day. <http://antwrp.gsfc.nasa.gov/apod/ap980531.html> Last Visited January, 2002.

Schaefer, Martha. "Mars Planet." Encarta, 2000.

Space Today, Tomorrow, and Always. </J0112188/> Last Visited: January 2002.

Spinrad, Hyron. "Mars." World Book Encyclopedia, 1999.  

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All pictures courtesy of NASA unless otherwise noted