Why Haven’t We Heard From All The Aliens? Because They’re All Dead!

Illustration of Kepler-186f, a recently-discovered, possibly Earthlike exoplanet that could be a host to life. (NASA Ames, SETI Institute, JPL-Caltech, T. Pyle)

In 1950, physicist Enrico Fermi raised a very important question about the Universe and the existence of extra-terrestrial life. Given the size and age of the Universe, he stated, and the statistical probability of life emerging in other solar systems, why is it that humanity has not seen any indications of intelligence life in the cosmos? This query, known as the Fermi Paradox, continues to haunt us to this day.If, indeed, there are billions of star systems in our galaxy, and the conditions needed for life are not so rare, then where are all the aliens? According to a recent paper by researchers at Australian National University’s Research School of Earth Sciences., the answer may be simple: they’re all dead. In what the research teams calls the “Gaian Bottleneck”, the solution to this paradox may be that life is so fragile that most of it simply doesn’t make it.To put this in perspective, let’s first consider some of the numbers. As of the penning of this article, scientists have discovered a total of 2049 planets in 1297 planetary systems, including 507 multiple planetary systems. In addition, a report issued in 2013 by the Proceedings of the National Academy of Sciences of the USA indicated that, based on Kepler mission data, there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way, and that 11 billion of these may be orbiting Sun-like stars.So really, there should be no shortage of alien civilizations out there. And given that some scientists estimate that our galaxy is 16 billion years old, there’s been no shortage of time for some of that life to evolve and crate all the necessary technology to reach out and find us. —> Read More