Mars is the fourth planet from the Sun. It is also one of our closest neighbours and because of this has often been talked about as a possible destination for humans. Many books have been written, and movies made about travelling and even living on Mars. It is easily visible from Earth with the naked eye. It often appears quite bright and reddish in the night sky. Mars was named after the ancient Roman God of War.
Mars is a dusty and rocky planet. It is believed that water may exist on Mars in the form of ice at its north and south poles. It is even possible that there is also water below its surface. Mars has a thin atmosphere which is mainly made up of carbon dioxide and would be poisonous to humans. No forms of life have yet been found on Mars but there may have once been. Even still the search for life on Mars continues. If any life-form exists on Mars today, many scientists believe it would be tiny organisms in protected niches just below the surface.
Over the centuries, many people have noted various features on the Martian surface, some of which they thought might be signs of life. For instance, dark markings cover about a third of the surface and change in colour depending on the season. They were once thought to be vast seas or areas of vegetation. A few astronomers even thought they saw straight lines that could have been canals. Scientists now know that there are no manufactured canals on Mars. The changes in the dark areas result largely from dust, which shifts along with the winds. One photograph taken of the surface of Mars even looked like a giant face but was later shown to be just shadows on the surface of Mars.
Now we know a lot more about Mars. We know for example that the biggest Volcano in the Solar System is on Mars. Its is called Olympus Mons and is 27km high. That’s over 3 times the height of Mt. Everest. We also know that Mars has seasons just like Earth. Spring and summer in the north last more than half the year. In the south the summer is shorter. Mars is also much colder than Earth. The temperature on the Martian surface varies widely during the course of a day, from about -83°C just before dawn to about -33°C in the afternoon. Mars also has many global dust storms carried by strong winds. A year on Mars is equal to 687 days. Mars spins on its axis at about the same rate as Earth so each day is roughly the same as here on Earth. Mars has two moons. They are named Phobos (‘Fear’) and Deimos (‘Terror’) after the sons of Ares, the Greek god of war.
From the 1960s to the 1980s, The United States and the Soviet Union sent many spacecraft to Mars. Scientists were able to gather data in the form of photographs and other observations in these missions. This information helped scientists to understand more about the geography and atmosphere of the planet. Beginning in the mid-1990s, missions to Mars became more elaborate. NASA sent the Mars Pathfinder to land on the planet and the Mars Global Surveyor to orbit Mars. They both arrived in 1997 and sent back information about the surface, interior and atmosphere of Mars. In April 2001 NASA launched another orbiting satellite, the Odyssey. The Odyssey gathered further information about the planet. It also helped NASA scientists communicate with two craft, called rovers, that were sent to Mars in 2003. The rovers – called Spirit and Opportunity – landed in late 2003 and early 2004.
If you look at the pictures on the Opportunity and Spirit pages you might notice that they resemble a certain Movie Character. Can you guess who?
Click the question mark to see if you were right.