Our Solar System .... Mars.
Mars is the fourth planet from the Sun and is commonly referred to as the Red Planet.
The rocks, soil and sky have a red or pink hue. The distinct red colour was observed by stargazers throughout history.
It was given its name by the Romans in honour of their god of war. Other civilizations have had similar names.
The ancient Egyptians named the planet Her Descher meaning the red one.
Before space exploration, Mars was considered the best candidate for harbouring extraterrestrial life.
Astronomers thought they saw straight lines crisscrossing its surface. This led to the popular belief that
irrigation canals on the planet had been constructed by intelligent beings. In 1938, when Orson Welles broadcasted
a radio drama based on the science fiction classic War of the Worlds by H.G. Wells, enough people believed in the tale
of invading Martians to cause a near panic.
Another reason for scientists to expect life on Mars had to do with the apparent seasonal colour changes on the planet's
surface. This phenomenon led to speculation that conditions might support a bloom of Martian vegetation during
the warmer months and cause plant life to become dormant during colder periods.
In July of 1965, Mariner 4, transmitted 22 close-up pictures of Mars. All that was revealed was a surface containing many
craters and naturally occurring channels but no evidence of artificial canals or flowing water. Finally, in July and September
1976, Viking Landers 1 and 2 touched down on the surface of Mars. The three biology experiments aboard the landers discovered
unexpected and enigmatic chemical activity in the Martian soil, but provided no clear evidence for the presence of living
micro-organisms in the soil near the landing sites. According to mission biologists, Mars is self-sterilizing. They believe
the combination of solar ultraviolet radiation that saturates the surface, the extreme dryness of the soil and the oxidizing
nature of the soil chemistry prevent the formation of living organisms in the Martian soil. The question of life on Mars
at some time in the distant past remains open. Other instruments found no sign of organic chemistry at either landing site,
but they did provide a precise and definitive analysis of the composition of the Martian atmosphere and found previously
undetected trace elements.
The atmosphere of Mars is quite different from that of Earth. It is composed primarily of carbon dioxide with small amounts
of other gasses. Martian air contains only about 1/1,000 as much water as our air, but even this small amount can condense
out, forming clouds that ride high in the atmosphere or swirl around the slopes of towering volcanoes. Local patches of
early morning fog can form in valleys. At the Viking Lander 2 site, a thin layer of water frost covered the ground each
winter. There is evidence that in the past a denser Martian atmosphere may have allowed water to flow on the planet.
Physical features closely resembling shorelines, gorges, riverbeds and islands suggest that great rivers once marked the
The average recorded temperature on Mars is -63° C (-81° F) with a maximum temperature of 20° C (68° F) and a minimum
of -140° C (-220° F). Carbon dioxide, the major constituent of the atmosphere, freezes out to form an immense polar cap,
alternately at each pole.