These can vary from a storm over a small area, to gigantic storms that cover the entire planet. They tend to occur when Mars is closest to the Sun, increasing global temperature. Though it is often referred to as the Red Planet, Mars actually has many colors.
At the surface colors such as brown, gold and tan are present. Mars has many evidences of a watery past, with ancient river valley networks, deltas and lakebeds, as well as rocks and minerals on the surface that could only have formed in liquid water.
Some features suggest that Mars experienced huge floods about 3. Near the northern polar cap is the There are two permanent polar ice caps on Mars. When they are exposed again to sunlight the carbon dioxide sublimates and sometimes create water-ice clouds. The dichotomy of Martian topography is striking, northern plains flattened by lava flows contrast with the southern highlands, pitted and cratered by ancient impacts.
Mars is scarred by a number of impact craters: a total of 43, craters with a diameter of 5 km 3. The largest confirmed of these is the Hellas impact basin, a light albedo feature clearly visible from Earth. The volcano Olympus Mons, is an extinct volcano in the vast upland region Tharsis, which contains several other large volcanoes. Olympus Mons is however the greatest, in fact it is the largest volcanoe detected in the entire Solar System, it has about three times the height of Mount Everest.
The large canyon, Valles Marineris also known as Agathadaemon in the old canal maps, has a length of 4, km 2, mi and a depth of up to 7 km 4. The length of Valles Marineris is equivalent to the length of Europe and extends across one-fifth the circumference of Mars. By comparison, the Grand Canyon is only km mi long and nearly 2 km 1.
Valles Marineris was formed due to the swelling of the Tharsis area, which caused the crust in the area of Valles Marineris to collapse. It is 10 times longer and 10 times wider than the Grand Canyon. Mars also has sand on its surface, made up from basaltic rock, thus having a grey color. When the wind blows, dunes are created including series of parallel ridges in crater floors, also horseshoe-shaped dunes are created. Mars also has dust devils, towering vortices of wind similar to tornadoes.
When the dust devils blow the red dust around on the greyish basaltic plains, they can leave behind complex and beautiful curlicues. Mars actually has avalanches. Cliffs towering above the surface that hold different materials can be dislodged in the spring when carbon dioxide thaws, creating tremendous cascades of rock and dust. Once upon a time, though, wind and water flowed across the red planet.
Not so today: Though water ice abounds under the Martian surface and in its polar ice caps, there are no large bodies of liquid water on the surface there today. Mars also lacks an active plate tectonic system, the geologic engine that drives our active Earth, and is also missing a planetary magnetic field. But in the ancient past—up until about 4.
What shut down the Martian dynamo? Scientists are still trying to figure out. The peak is so massive, it curves with the surface of Mars. If you stood at the outer edge of Olympus Mons, its summit would lie beyond the horizon. The gorges span about 2, miles and cut up to 4.
The valleys get their name from Mariner 9, which became the first spacecraft to orbit another planet when it arrived at Mars in About 4.
The highlands of the southern hemisphere, however, are studded with many extinct volcanoes, and the crust there can get up to 62 miles thick. What happened? At some point in the distant past, the red planet gained its two small and irregularly shaped moons, Phobos and Deimos. The two lumpy worlds, discovered in , are named for the sons and chariot drivers of the god Mars in Roman mythology. How the moons formed remains unsolved. But recent models instead suggest that they could have formed from the debris flung up from Mars after a huge impact long ago.
Deimos, the smaller of the two moons, orbits Mars every 30 hours and is less than 10 miles across. Its larger sibling Phobos bears many scars, including craters and deep grooves running across its surface. Scientists have long debated what caused the grooves on Phobos. Since the s, humans have robotically explored Mars more than any other planet beyond Earth.
Currently, eight missions from the U. But getting safely to the red planet is no small feat. He also discovered a strange feature on the planet that became known as Syrtis Major. On November 28, , Mariner 4 was launched successfully on an eight-month voyage to the Red Planet. It made its first flyby on July 14, , collecting the first close-up photographs of another planet.
The pictures showed many impact craters, some of them touched with frost in the chill Martian evening. The Mariner 4 spacecraft was able to function for about three years in solar orbit, continuing long-term studies of the solar wind environment and making coordinated measurements with Mariner 5.
Galileo was found guilty of heresy and was sentenced to life imprisonment and forced to recant. In secret, he wrote another book, which was smuggled out of the country and published in France. His work is now considered the foundation of modern physics.
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