The reason why we haven’t found any signs of alien civilizations could be rather simple, according to the idea that alien life may be extinct due to rapid climate change. This concept comes from two astrobiologists the Australian National University, Charley Lineweaver and Aditya Chopra and the study was published in the journal Astrobiology.
Their idea comes as an alteration to the Fermi paradox. This theory can be basically summarized as a complete contradiction between the probability of extraterrestrial life existing in the Universe and our lack of evidence concerning its existence. There are an almost infinite number of stars and planets present in the universe, which in turn causes the probability of alien life rather high.
Up to this point, Kepler has discovered over 1,000 potentially life-sustaining planets that have a Goldilocks orbit around a Sun-like star, not too close and not too far. But the idea coming from the two astrobiologists states that evolution from microbial life to multicellular stages is too slow for it to exist given the rapid climate changes present on such planets.
For instance, in ancient times, Earth, Mars, and Venus could have all housed microbial life. But Mars lost its atmosphere at a fast rate while Venus became too hot to sustain life. On the other hand, Earth’s climate change was somewhat slowed by the large quantity of cyanobacteria that released oxygen into the atmosphere, effectively regulating the amount of greenhouse gasses present, making the planet habitable.
If microbial life isn’t able to keep up the pace when it comes to planetary changes, it will become extinct. Another theory would be that this type of alien life would simply stop evolving at one point due to the limitations installed by the planet itself. Scientists will gain a greater deal of knowledge in regards to this idea once we pierce Europa’s icy shell.
The moon is covered in ice but it is generally considered that beneath its crust, large oceans are present alongside thermal vents that keep the interior at a constant temperature. This could function as a type of incubator for microbial life, but this is still in the realm of allegations until we will actually be able to gather viable evidence from the moon.
The alleged fact that alien life may be extinct due to rapid climate change may be extensively viable if we take into account how no signs of alien life have been discovered up to this point. The only hints that extraterrestrial life would have been present on a planet will more than likely be unicellular fossils instead of dinosaur or proto-humanoid remnants.