For decades we have been searching for traces of life on Mars. Why? Probably out of curiosity, scientists know that the universe is so large that it is quite impossible that we are the only ones living in it. Considering our choices and the vastness of the universe or even our solar system, Mars is the only planet that we can easily reach and observe.
Before we were able to take a single picture of Mars, many of us already believe that little green men lived in Mars. Many movies showed Martians as such, they were highly advanced in terms of technology and quite friendly in nature. But all these beliefs were wiped out when Mariner 4 took a picture of Mars and it showed dry sandy surfaces with lots of craters just like the moon.
Hopes were down but the government decided to give it one more shot by sending the Vikings to further study the planet. The Viking took 16,000 images of Mars and atmospheric studies that suggests water in Ancient Mars.
From then on, the quest for life on Mars became the quest for liquid water on Mars. Since there seemed to be life wherever there is water, scientists believe that if we can only find minute traces of water in Mars in will not be surprising if we find life. Now, life doesn’t have to be multi-cellular organisms, a single celled organism is enough to prove that life exists or existed on Mars and it would also be enough to prove that we are not alone in the universe.
Since then different missions have been successfully feeding us data about Mars. Currently, the Phoenix Mars Lander discovered water ice on Martian soil, these bits and pieces of information is getting us closer to our goal of finding liquid water on Mars and eventually life.
Here is great 5 part video that discusses our quest for life or water on Mars