The recent discovery of a great number of potentially habitable exoplanets raises the Fermi paradox again: why haven’t we still come into contact with aliens? Climatologists might have finally given a plausible answer.
The great physicist of the 20th century Enrico Fermi, when asked about the possibility of the existence of extraterrestrial civilizations, answered with a counter-question: “So where are they?”
According to the scientist, any intelligent species after having reached the level of interstellar travel would inevitably fill the entire galaxy, including our Earth, in a short (by cosmic standards) period of time.
Many experts have tried to find the answer to the Fermi paradox. Some of them question the fundamental feasibility of interstellar travel, while others believe that any intelligent civilization, in the end, must self-destruct.
Each discovery of a new potentially habitable exoplanet raises the question of extraterrestrial intelligence. According to current estimates, only in the Milky Way there must be hundreds of millions of planets suitable for life.
More recently, a rocky exoplanet with a mass equal to 17 Earths was discovered. Previously it was thought that the atmosphere of such celestial bodies should be so dense that the temperature and pressure at their surface would not allow them to sustain life.
However, as it turned out, “Mega-Earth” has a relatively thin atmosphere, which means that there is a completely new major category of potentially habitable worlds.
So why hasn’t mankind still come in contact with extraterrestrial intelligence?
It is possible that the cause lies in climate change. At the same time, it is not necessary that the intelligent life should self-destruct with the constant rise of the temperature of the biosphere. Stellar evolution can lead to the fact that the climatic conditions may get worse long before the intelligent life emerges on the planet.
But then how to explain the fact of our existence on Earth?
According to calculations, the surface temperature of the Sun has increased by 4% over the past 500 million years, which means that the temperature on Earth would be increased by 10° C. However, current data suggest rather the opposite effect.
If you extrapolate the data for the entire history of life on Earth, in four billion years, the average temperature would be increased by 100° C, i.e. the first living organisms were to appear in permafrost. But scientific data show that at that time our planet was already covered by oceans.
The answer given by scientists is simple and yet surprising: Earth was incredibly lucky. Geological and then biological processes on our planet were combined with the increasing flow of heat from the sun.
The Earth’s atmosphere has evolved in such a way that it was able to effectively reflect the sunlight, keeping the perfect climate necessary for the development of life on the planet over billions of years, the evolution of which eventually led to the emergence of intelligent species – humans.
It is highly unlikely that among the hundreds of millions of potentially habitable worlds there is a large number of planets capable of regulating their climate for a sufficiently long period of time before the emergence of intelligent species. It is quite possible that this is the answer to the Fermi paradox.