If you have a chance to go to a country side where you may have a clear view of the sky at night, you probably will discover a red star. That is probably Mars. With its bright and reddish color, Mars stands out for and easily noticed since the ancient times (Discovery). In 1877, astronomer Giovanni Schiaparelli discovered several crisscrossing lines on Mars that he believed to be the canals of water (Discovery). Go along with the hypothesis that life existed on Mars, several processes has been made to prove hypothesis. However, is there really lives on Mars or people are just wasting their times and money to prove the thing that never exists?
Mars is a one of five planets that can be seen from Earth without using a binocular or a telescope. With that, it is well-known in every culture since long time ago. The official name for it "Mars" is adopted by the Roman, in honoring of their god of war; MARS because the reddish color remind everyone of blood and death (Discovery). It is also known as the "Red Planet" due to its reddish appearance from observation on Earth (Mars-Wikipedia).
With the effects of fictions and media like the movie War of the Worlds of H.G Wells that emphasizes on the existence of the Martians, another kind of intelligent creatures other than Earthman (Mars-Wikipedia). That creates more attention to Mars from people more than any other planets.
Living on Earth, an environment which you can find "life" exist everywhere you go, every step you put on the ground, every times you breath, there are millions of micro-living-form. It probably difficult for us to have clear understanding that not every other environment be suitable for life to exist, at least at the definition standards of how we, human, define: life. According to Shostak in his article, there are three requirements for life to exist: there must be raw materials, solvent, (water is considered as a priority choice), energy to drive the whole system to work (Shostak). Let apply this to the environment of planet Earth. We have raw materials: rock, coal, phosphor, sulfur, etc. This is necessary for the plant to develop on soil. Water is also another excess substance on our planet. We have enough water to keep all creatures alive. Plant, the base for all complex creatures to exist or other animals is both depend on water to transport substances inside its bodies. Don't forget that the Earth also receive large amount energy from the Sun everyday. That amount of energy helps the plant to transform carbon dioxide into oxygen for all creatures to use. Earth has all of the requirements, and the result is we have life on Earth.
Is Mars all qualified for this logic? If the answer is yes, life can be concluded to be existed on that blood-color planet. For the raw material requirement, it is probably not a problem on a rocky planet like Mars. The handful of elements necessary for life is available just about everywhere. The latter two requirements are coupled, since energy is necessary to keep fluid liquefied (Shostak). Mars is closer to the Sun than Earth, there is no reason that it is not receive enough energy for life to get working. However, there is one point that scientist has not discovered is if water or any kind of solvent exists on that dry planet.
By the mid 19th century, astronomers have known that Mars had certain similarities to Earth (Mars Wikipedia). One is both Earths and Mars have the same day's length (Mars Wikipedia). In addition, Mars' axial tilt was similar to Earth's, the length of each seasons on Mars compare to its year is in perspective as the lengths of season on Earth to Earth's year (Mars Wikipedia). Before human made any exploration to Mars, there was hope with the observations of periodic variations in light and dark patches, particularly in the polar latitudes, and long dark striations that could perhaps even be irrigation channels of liquid water. These observations led to the...