In a recently released scientific model known as the Gaian Bottleneck, researchers are now suggesting that alien life is already extinct, and that’s why we’ve never been contacted by extraterrestrial beings.
The study was conducted by astrobiologists at the Australian National University (ANU), and its findings have been featured on Thursday, January 21, in the journal Astrobiology.
Dr. Charles Lineweaver, associate professor of physical and mathematical sciences, worked alongside Dr. Aditya Chopra, affiliated with the Research School of Earth Sciences.
Together, they determined that even though there may be numerous habitable planets, strewn across the universe, the probability that their conditions can remain stable enough in order to allow life to evolve is actually extremely low.
This theory is known as the Gaian Bottleneck, and has been thoroughly detailed in the newly released study. Basically, what scientists are now inferring is that finding habitable worlds doesn’t really bring us any closer to discovering intelligent extraterrestrial life forms, because such creatures never even existed in the first place.
Apparently, even if a distant world were to fulfill all the requirements needed for it to support life, such hospitable conditions would only be maintained temporarily, allowing just simple microorganisms to flourish.
In a relatively short while, the planet would undergo a process of thermal runaway, or on the contrary experience exceptionally rapid cooling. As a result, organisms that were just beginning to appear would soon be obliterated, to the point where the evolution of life would be halted in its tracks.
Thus, more advanced life forms would never manage to emerge, and the planet would once again become a barren, inhospitable world.
This may explain Fermi’d paradox, which emphasizes how surprising it is that no traces of alien civilizations have ever been found, although the vastness of the universe suggests there’s a high probability that habitable, Earth-like planets do indeed exist.
Researchers have been supporting their Gaian Bottleneck hypothesis with two examples from our own galaxy: Venus and Mars.
While it’s true that 4 billion years ago the two planets were probably able to support life, just like Earth, they never maintained their hospitable conditions. Instead, the Red Planet turned excessively cold, while the Morning Star became excessively hot.
On both these planets, microbial life was never able to evolve or to become stable enough, and that’s why the Earth is now surrounded just by lifeless worlds, with little hope of ever finding cognizant alien beings.
Experts at the SETI (Search for Extraterrestrial Intelligence) Institute have been quick to reject the Gaian Bottleneck hypothesis, claiming that some life forms may be able to adapt even to unfavorable environmental conditions.
For instance, senior astronomer Seth Shostak believes that while “early Armageddon” on distant planets is indeed a likely scenario, sometimes changes triggered by mass extinctions actually allow certain species to flourish, and to evolve into more and more advanced creatures, that could even become sentient.
That’s exactly what happened on our planet, when natural cataclysms helped life forms become more diverse and advanced, with human beings eventually becoming the pinnacle of evolution.
In response, Chopra and Lineweaver have declared that they have full faith in their Gaian Bottleneck theory. As they explained, Earth proved to be an exception to the rule, because organisms were able to keep greenhouse gases within optimal boundaries, thus allowing surface temperatures to remain at relatively steady values.
However, more often than not, life at its earliest beginnings is overly fragile, and fails to adapt rapidly enough in order to thrive.
As a result, the two study authors now predict that even if fossils were to be found on other planets, they would surely pertain to microbial organisms, not to more complex creatures whose evolution would have to span across millions or billions of years.
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