Mars, it is the fourth planet from the sun. It is closet planet to earth. Mars is the planet with more solar exploration than any other planet in our universe. Mars is the one planet that has an atmosphere similar to ours. Mercury, Venus, and Pluto have had all of their atmospheres burned off and Jupiter, Saturn, Uranus, and Neptune all have atmospheres that are hundreds of time more violent than the calm atmospheres of Earth and Mars. Mars is also the only planet in which we have identified that there was once water on the surface of the planet. We have discovered huge canyons that resemble the ones on Earth. This is also the reason why we believe that the Red Planet might have once had or still does have life on it."
Before space exploration, Mars was considered the best candidate for harboring extraterrestrial life. Astronomers thought they saw straight lines crisscrossing its surface.
Orson Welles, March 1, 1937
Mars, 2001, with the southern polar ice cap visibl...
Mosaic image of Mars as seen by Viking 1, 22 Febru...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 color 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. The interior of Mars is known only by inference from data about the surface and the bulk statistics of the planet. The most likely scenario is a dense core about 1700 km in radius, a molten rocky mantle somewhat denser...