MARS

M a R s

Mars known as the red planet, is the fourth planet from the sun and the outermost rocky planet. In the 19th century, astronomers first observed what ere thought to be signs of life in Mars. These signs included apparent canal like marking on the surface, and dark patches that ere thought to be vegetation. It is now known that the "canals" are an optical illusion, and the dark patches are areas where the red dust that covers most of the planet has been blown away. the fine dust particles are often whipped up by winds into dust storms that occasionally obscure almost all the surface. Residual dust in the atmosphere gives the Martian sky pinkish hue. The northern hemisphere of Mars has many large plains formed of solidified volcanic lava, where as the southern hemisphere has many craters and large impact basins. There are also several huge, extinct volcanoes, including Olympus Mons, which at 600 kilometers across and 25 kilometers high, is the largest known volcano in the solar system. The surface also has many canyons and branching channels. The canyons are were formed by movements of the surface crust, but the channels are thought to have been formed by flowing water that has now dried up. the Martian atmosphere is much thinner than Earth's with only a few clouds and morning mists. Mars has two tiny, irregularly shaped moons called Phobos and Deimos. Their size indicates that they may be asteroids that have been captured by the gravity of Mars.