The History Of Mars

Also known as “The Red Planet,” Mars received its name from the Roman god of war. To the Greeks, the planet was known as “Ares,” or war god. It is known as “The Red Planet” because its rocks and soil are a reddish color, and the Romans and Greeks felt this was similar to blood spilled during a war.

The reddish color of the soil is due to a large amount of iron being present, and as one of Earth’s closest neighbors, its surface features are often viewed using a telescope, and lengthy debates have arisen about the possibility of life on Mars. Scientists believe Mars is 4.6 billion years old.

The Orbit Of Mars

The orbit of Mars is oval in shape, with a more elongated pattern than many of the other planets. On Mars the Sun “rises” in the East and “sets” in the West. The perihelion, or point at which the planet is closest to the sun, is 128 million miles (207 million km), whereas its aphelion, or the point at which the planet is farthest from the sun, is 155 million miles (249 million km). Depending on the orbits of Mars and Earth, the two planets can be as far away as 249 million miles (401 million km) or as close as 34 million miles (54 million km). The orbit of Mars is approximately 687 Earth days, while a day on Mars is 24 hours and 37 minutes.

As a result of Mars tilting on its axis, the Sun will only reach various areas of the Martian surface, resulting in seasons being produced like here on Earth.

Expeditions To Mars

There have been numerous successful expeditions to Mars because of its close proximity to Earth. The first expedition to occur was by the United States in 1964 using the Mariner 4 spacecraft. This was followed in 1969, by Mariner 6 and Mariner 7 spacecrafts, to each visit the atmosphere of this planet. Mariner 9 was then placed into orbit around Mars in 1971. It was successful in detailing 90 percent of the surface features currently known about this planet.

The next expedition to Mars was the Viking Mission. Its main purpose was to land on Mars, and look for signs of life on the planet. This occurred between 1975 and 1976, and was the first expedition to have the spacecraft land on Mars. The Viking Mission was successfully able to take soil samples, but was unsuccessful at finding life on Mars.

In 1996, the Mars Pathfinder and the Mars Global Surveyor were the next missions launched to Mars. The Pathfinder was sent to land on the planet, whereas the Global Surveyor was only sent to orbit around it.

The Mars Pathfinder was able to touch down in 1997. It released a small rover called Sojourner. Sojourner traveled over Mars sending detailed photographs back to Earth of the planet’s surface.

Even though it only orbited Mars, the Global Surveyor spacecraft had the important task of determining the height of different elevations on “The Red Planet.” This was done using a laser beam. It was also instrumental in creating maps of the Martian surface.

The United States then launched the Mars Odyssey Mission probe in 2001. The orbiting probe was able to analyze the surface of Mars and confirm the presence of water ice, available in large quantities at the poles.

Following this expedition to the planet, the European Space Agency sent spacecrafts during the Mars Express Mission in 2003, while the United States launched the Spirit and Opportunity Missions. Spirit and Opportunity’s main functions were to confirm the presence of liquid water on Mars, while measuring sulfur levels in the soil and rocks. Spirit and Opportunity were able to transmit data for more than the originally planned 90 days.

The most recent expedition to Mars was the Mars Reconnaissance Orbiter, which was sent from Earth in August 2005. It arrived on Mars in March 2006, and is expected to look for interesting areas on the Martian surface to explore.

Exploring A Day On Mars

Time-wise, a day on Mars is only a couple of minutes longer than a day on Earth, however staying a Martian year would be more than 600 Earth days.

Mars does not have a thick cloud cover like Venus, and the composition of oxygen in its atmosphere is only 0.13 percent, compared to 21 percent on Earth. The highest concentration of any gas on Mars is carbon dioxide, with a level of 95.3 percent.

The temperature of Mars varies depending on the altitude someone is standing at. At higher altitudes, the temperature is around – 266 degrees Fahrenheit, but it can reach 20 degrees Fahrenheit closer to the surface.

While On Mars, it would be apparent that the landscape is similar to Earth. Mars contains similar plains, valleys, volcanoes, and other geographical features found on Earth. Most of the plains on Mars are located within its Northern hemisphere, while most of the canyons are more distributed around its Equator. These canyons have been termed the “Valles Marineris”, and it occupies a distance of about 2,500 miles.

Even though someone would think the largest volcanoes would be on Venus or Earth, they are actually located on Mars, with many of them resembling the shape of volcanoes found in Hawaii.

Like Mercury, it is evident while exploring Mars, impact basins and craters are also part of its geography. These impact basins and craters are more common in the Southern hemisphere of the planet. The most famous one is the Hellas Impact Basin with a measurement of 1,300 - 1,400 miles in width.

Based on the presence of carbon and liquid water, Mars is the most likely planet of the planets to have life, if it is present. It has been debated in the past few years that Mars at one time in its history could have possess other life forms, or life forms are hiding in cracks or caves. However, to date no life forms have been found on Mars.

The Satellites Of Mars

There are two satellites associated with Mars – Deimos and Phobos. They were discovered in 1877 by Asaph Hall. Both of these tiny moons are not completely circular, with Phobos having an average diameter of 13 miles, and Deimos being approximately 8 miles in diameter. Phobos orbits Mars every 11 hours, while Deimos completes a full orbit in 30 hours.

The surface of Deimos and Phobos is unremarkable and similar to Earth’s moon, with numerous craters and impact basins. It is believed that Deimos and Phobos are really asteroids captured in the gravity of Mars.

Statistics About Mars

References

Encyclopedia Britannica. "Mars.” 2006. Encyclopedia Britannica Premium Service. 2006 http://www.britannica.com/eb/article-54222

National Aeronautics and Space Administration (N.A.S.A). “Mars: Facts & Figures.” 2006 http://solarsystem.nasa.gov/planets/profile.cfm?
Object=Mars&Display=Facts

Squyres, Steven W. "Mars." 2004. World Book Online Reference Center. World Book, Inc. http://www.worldbookonline.com/wb/Article?
id=ar346000

Mars Images