MARS MISSIONS FINDINGS AND REASONS FOR THE QUEST
Mars, the fourth planet from the sun and the seventh largest, is a favourite among astronomers at NASA. ... It is believed that although there are no present signs of life (none that have been found as to date that is) there was once enough resources within the planet to support life on Mars. It’s for this reason that there have been so many successful and non-successful missions to mars. Mars has been known since prehistoric time. In early history, mars was much like Earth, almost all of its carbon dioxide was used up to form carbonate rocks. But lacking the Earths plate tectonics, Mars is unable to recycle any of this carbon dioxide back into its atmosphere and so cannot sustain a significant greenhouse effect. The surface of Mars is therefore much colder than the Earth would be at that distance from the Sun. Mars is the last of the "inner planets. ... Mars is about half the size of Earth and has two moons, Phobos and Deimos. ... Although Mars does have seasons, the temperature only varies from cold to extremely cold. Mars is smaller and, because of its greater distance from the Sun, cooler. ... Interestingly, unlike Earth the significant eccentricity (elliptical shape) of the martian orbit means that the seasons on Mars are also affected by varying distance from the Sun. ... Missions to Mars over the past decades have been plenty and there are still plenty more to come. ... How does the composition of Mars differ from the Earths and how have the two planets evolved differently? ... How does the composition and state of the interior of Mars differ from the Earths? ... Is Mars still geologically active? ... Was there an early dense atmosphere on Mars? ... Did Mars once have oceans? ... What changes in climate has Mars experienced over its geologic history and what caused those changes? ... How stable is the climate of Mars today? ... Did chemical evolution take place on Mars – leading to the formation of prebiotic organic molecules? ... If life once arose, is it to be found anywhere on Mars today? (Center For Mars Exploration, http://cmex-www. ... htm) Since our first close-up picture of Mars in 1965, spacecraft voyages to the Red Planet have revealed a world strangely familiar, yet different enough to challenge our perceptions of what makes a planet work.