Wondering why aliens, if they exist, have not showed up on Earth yet? Well, this is because early life forms went extinct soon after their existence, according to a team of astrobiologists. The paper is published in the journal Astrobiology.
If life ever sprouted on other planets in the latter’s early days, it would have been short-lasting. Such is the conclusion of astrobiologists from The Australian National University (ANU). The researchers have named this concept the Gaian Bottleneck. One of the prediction of the Gaian Bottleneck is that most fossils in the universe would come from microbial life having gone extinct, and not from evolved multicellular species – dinosaurs or humanoids – because these would need billions of years to develop.
Why can’t life be sustained on the ‘habitable planets’ (as many scientists like to think of them) in the universe? Answering this question, lead author Dr Aditya Chopra from the ANU Research School of Earth Sciences, mentions the fragility of early life, explaining that, generally, it would not evolve fast enough to be able to survive. The team deduced that life on other planets would be destroyed as a consequence of runaway heating or cooling because, as Chopra points out, the majority of “early planetary environments” are not stable. Rather, for surface temperatures to be kept stable, greenhouse gases have been be regulated by the life forms.
The researchers suggest that besides Earth, Venus and Mars might have also been habitable once. Still, Venus became extremely hot while Mars froze only a billion years following their formation. This would have been the result of the failure of early microbial life (if it ever existed on the two planets) to strike a balance in the fast-changing environment. On the other hand, life on our planet is likely to have been fundamental in stabilising its climate.
According to Chopra, their explanation can solve the mystery as to why signs of aliens have not been found. Aliens have not contacted us, not because of issues of intelligence or pertaining to the origin of life, but because sufficiently-rapid evolution of biological regulation of the planetary surfaces is rare; the life that did exist at the beginning could not evolve to stabilise the environment for its existence to be sustained, and it, therefore, went extinct. This early extinction, would explain it all.
So, you can kiss goodbye to the possibility of having humanoids, alien creatures, monsters, and what not, from the other planets contacting us.