Out of the billions of solar systems, there has to be a chance that a least a couple planets have the ability to support life. Life may have developed on the planets like life developed here, but it may have developed differently also. Are they more intelligent than we are or are they single-celled organisms? It goes back to how life on Earth started. In the early days of Earth, we learned that the atmosphere was just carbon monoxide, but plants produced oxygen. Some of earth's fossil records indicate that within a billion year period of it's formation as a planet, as soon as heavy bombardment by asteroids ceased, primitive organisms such as bacteria and algae evolved and spread around the globe very quickly. This mystery makes it hard for us to figure out how life would arise on other planets. In order to help people figure out what planets out there could support life and may have life on them, we have to look at what life needs to survive. It is believed that if a planet looks like Earth and has liquid water and oxygen, then this would present strong evidence for its having life. If there is other life out there, what are the chances of finding it in our lifetime, or even our children's lifetime. Conditions have to be just perfect to develop life. But under the right circumstances life can arise. The question still stands. Does life exist on other planets? Are they intelligent? Will we ever really know?.
