Mars has some of the most highly varied and interesting terrain of any of the terrestrial planets, some of it quite spectacular: Olympus Mons: the largest mountain in the Solar System rising 24 km (78,000 ft. Mars has been known since prehistoric times. Mars' relatively low density compared to the other terrestrial planets indicates that its core probably contains a relatively large fraction of sulfur in addition to iron (iron and iron sulfide). Mars' atmosphere now seems to be both colder and dryer than measured by the Viking Landers (more details from STScI). Mars has a very thin atmosphere composed mostly of the tiny amount of remaining carbon dioxide (95. Mars is a difficult but rewarding target for an amateur telescope though only for the three or four months each martian year when it is closest to Earth. Mars in particular was, and is still, considered as the most earth-like of all planets, as it shows polar caps, an atmosphere with meteorological activity over a stony surface, a comparable rotation period (length of day), seasonal variations, and a temperature not too different from that of Earth, compared to every other planet of our solar system.

Mars

Mars was called Mavōrs in some poetry (Virgil VIII, 630), and Mamers was his Oscan name. Mars' bright appearance and reddish color stand out in the night sky. Mars is about half the size of the Earth. Mars is the fourth planet from the Sun and is commonly referred to as the Red Planet. Mars is the only planet where the average backyard astronomer can actually see the seasons change. Mars is one of the first things people look at when they get their first telescope, and it can remain a favorite observation target for as long as they own the telescope.

Surface

Though Mars is much smaller than Earth, its surface area is about the same as the land surface area of Earth. The surface of Mars is therefore much colder than the Earth would be at that distance from the Sun.

Mars is named after the Roman god of war. Mars can be seen from Earth with the naked eye. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. Mars is also scarred by a number of impact craters: a total of 43,000 craters with a diameter of 5 km or greater have been found. Mars has half the radius of Earth and only one-tenth the mass, being less dense, but its surface area is only slightly less than the total area of Earth's dry land. Mars lost its magnetosphere 4 billion years ago, so the solar wind interacts directly with the Martian ionosphere, keeping the atmosphere thinner than it would otherwise be by stripping away atoms from the outer layer. Mars also has the largest dust storms in the Solar System. Mars orbits half an astronomical unit beyond this zone and this, along with the planet's thin atmosphere, causes water to freeze on its surface.

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Niel Hudgens is a successful Webmaster and publisher of www.AstronomistsUnlimited.com . He provides more information about astronomy and astronomy issues that you can research in your pajamas on his website.