For years people questioned whether or not the surface of Mars was or had ever been covered in vegetation, water or other forms of organic life (Dr. David R. Williams). After landing, the Viking rover successfully answered this question - yes. The machines used in the Viking missions discovered a vast amount of land formations that only occur in the presence of large, flowing water. While observing these outflow channels in the southern hemisphere of the planet, scientist were able to conclude that rainfall was once present. The images received showed that at one time water had battered the land creating vast valleys which stretched on for thousands of kilometers. Some channels are even estimated to flow up to ten thousand times that of the Mississippi River (). The images go beyond just a few water channels, scientists believe that the entire terrain of Mars used to be completely different than it is now. It is suspected that the planet was once covered in an immense amount of water, much like Earth. Chemical analysis by the Viking landers supports this theory as the data revealed that the surface was once completely immersed in water. It is believed that at the very least, bacterial life was once present on the planet’s surface based on the human understanding of evolution and …show more content…
When they were sent, the Viking landers were equipped to carry out three important experiments to determine whether or not there was life present on the rocky planet. One of these experiments was dubbed, the Labeled Release (or LR) apparatus. The function of the LR experiment, which was basically a robotic arm, was that it allowed the rover to scoop up trace amounts of foreign soil (from the surface and from under rock) and then mix it with a drop of water. The water itself carried nutrients and radioactive carbon atoms. Scientists anticipated that if there were life-forms, they would use up the nutrients and in response, release carbon dioxide or methane gas. The LR was equipped with a radiation detector to identify any of these chemical compounds. To limit the chance of outlying factors, several controlled experiments were designed. The rovers treated some samples with fluctuating heat and some with different exposure to light, leaving some samples in the dark for several months. In these cases, the idea was that the varying conditions would kill off any photosynthetic organisms. The control samples’ results were negative, however, the initial samples came back as positive. The team was astonished as they believed they had just found the first evidence for life on Mars. The crew’s excitement was short-lived as the tests that