Theories on the Existence of Alien Life

Contrary to what people might think, the idea of the existence of alien life is not a modern one.

Maxim Trevelyan
Writer, Ravenclaw

Contrary to what people might think, the idea of the existence of alien life is not a modern one. Cosmic pluralism, or the belief that there are other inhabited planets beyond earth reaches as far back as the second century, if not further back. So, it is no wonder that several theories developed about human contact with extra terrestrials. This article presents some of the more popular ones. 

I will start with two theories that show the humanity’s slight egoism. First is the Rare Earth hypothesis, developed by Peter Ward and Donald Brownlee. They state that evolution of life and sentience is incredibly complex, especially its continued survival, requiring an improbably combination of astrophysical and geological events and circumstances. That Earth, and consequently humans, is lucky in that regard, thus being one of the few planets with life. The other ego-centric theory was proposed by Dr. Peter Behroozi called “The Early Birds”. Behroozi supposes that in the whole picture of the birth of the universe, Earth was formed quite early and thus humanity is the first civilization to be formed, but not necessarily the last.

Dr. Aditya Chopra also celebrated humanity’s luck and ingenuity with The Gaian Bottleneck theory, where the idea is that an alien civilization existed, but supposed that it died off. Chopra says that it is possible that due to the slow evolution of alien life on their home planets, the civilizations could not adapt and as a consequence, failed to survive.

NASA, and other organizations, remind us quite often that what we understand as alien life might not be as we know it. A popular theory amongst scientists, it says that while alien life might exist, there are no little grey or green men, but rather microscopic life-forms or, according to Lord Martin Rees, non-organic machines.

Fermi Paradox is a very famous theory on alien life, but the main crux of it is “The Great Filter”. Earth was subjected to five mass extinction events, but despite it all, complex creatures have evolved on it. Perhaps other planets that supported life were subjected to planet changing events as well, but unlike the lifeforms of Earth, their creatures just simply did not survive the ordeal.

The Great Silence is a theory that I find most interesting as it is the closest theory to what we usually perceive as alien life and its interactions with humanity. Simply put, alien life exists and it is incredibly advanced, so they see humanity as not worthy of significant interaction besides observation and possible experimentation. Why would a giant bother with an ant?

What do I think? The answer that I usually give when someone asks me whether I believe in the existence of extra terrestrial life is the theory of a “Galaxy Far, Far Away”. The Universe itself is incredibly vast. The scientists believe that 46.5 billion light-years is the distance to the edge of the currently observable universe. Of that, we only scanned around 40.000 light-years of the universe. It is highly probable that alien life does exist, but it is incredibly far away from Earth, so far that our current technology cannot reach it.

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Sources
https://en.wikipedia.org/wiki/Extraterr ... in_fiction
https://pubmed.ncbi.nlm.nih.gov/26789354/
https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
https://www.forbes.com/sites/curtissilv ... 846662318d
https://aeon.co/ideas/to-find-aliens-we ... nt-know-it
https://en.wikipedia.org/wiki/Great_Filter
https://earthsky.org/space/meti-worksho ... at-silence