What is Extraterrestrial Life?
Extraterrestrial is defined as things located or that occur off of earth or not within the atmosphere of earth, while the term life is far more difficult to define. For the purposes of defining extraterrestrial life, it might be easiest to say, that life would be anything that is living, from single-celled organisms to multi-celled complex organisms (like plants or animals), that didn’t come from earth. Depending upon a person’s imaginations and theories, extraterrestrial life can conjure up the images of aliens with semi-humanoid features and with intelligence enough to eventually contact humans. Alternately, some people may view forms of life on other planets as mostly microbial in nature, and suggest that earth is the only planet where life in more complex forms evolved. Despite the fact that scientists have not yet found true evidence of extraterrestrial life, there are some theories that we found and accidentally killed small microbes on Mars during the Viking 1 and 2 explorations
Extraterrestrial life is a type of life that may exist outside of Earth. There is no proof of existence of this kind of life. Extraterrestrial forms, especially ones who are believed to be intelligent, are known as aliens. The study of alien life is called exobiology. The beliefs in extraterrestrial life forms came from the ancient Egyptians, Babylonians, and the Sumerians. This started around 7th century, B.C. At this time, atomists in Greece took the idea and argued about an eternal life and that there were “visitors watching”. Humans are made of carbon and water, which also may be true for other life forms. Silicon is usually considered the most likely alternative. There is evidence to suggest that silicon-based life is unlikely. Astronomers have failed to find the simplest precursors to silicon-based biochemistry. Complex carbon-based compounds are abundant in space, but in the case of silicon, most of what we have observed in space are simple oxides of silicon.
