The question of Martian life is an age-old one. There are many theories on the history of Mars, and its inhabitants, or lack thereof.
The history and origin of Mars is widely debated, mostly between evolutionists and creationists, though the debate is mainly focused on the origin of the Universe, and not Mars specifically. Nevertheless, since Mars is part of the Universe, its origin must have been included in the origin of the Universe (McGuire). Evolutionists hold the belief that the Universe was formed by various gases combining and creating a "big bang" which, in turn, formed the planets. Creationists argue that this is too random an event, and on to great a scale to form all the microscopic complexities of organisms, and the great expanses of the Universe. Creationists believe that God (or some form of deity) Created the Universe by divine power, and that the above mentioned complexities could only be achieved by a Supreme Being.
The age of Mars has been reported to be between 3.6 billion and 1.3 billion years old, "depending on who you ask" (Erjavec, 1). These ages come from the estimated ages of meteorites found on Earth that are believed to have originated on Mars (Meteorites from Mars, 1). The meteorites were dated using radiometric dating methods (Erjavec, 1).
The most widely accepted theory of life on Mars is that of the recently conceived primitive, or microscopic, life may have existed on early Mars. "A NASA research team at the Johnson Space Center and at Stanford University has found evidence that strongly suggests primitive life may have existed on Mars more than 3.6 billion years ago" (Release: 96-160, 1). Many meteorites have landed on earth, but only 12 are believed to have originated on Mars. These 12 were determined to be from Mars...