Humanity has not yet established contact with extraterrestrial civilizations or has not found traces of extraterrestrial life because most of the potentially inhabited planets are most likely formed by ice-covered water worlds, said Alan Stern, the head of the New Horizons mission, at the annual planetary conference DPS in the US Provost.
“Oceans worlds are one of the most ideal environments for the birth of life, the conditions in the waters of such planets are almost independent of which stars they revolve around, how far away they are from them and how long such a star has to live.” They are not threatened by supernova explosions , meteorite impacts, sudden climate changes and other events that can destroy life on Earth, “explains Stern.
More than half a century ago, the American astronomer Frank Drake developed a formula for calculating the number of civilizations in the Galaxy, with whom contact is possible, trying to assess the chances of discovering extraterrestrial intelligence and life.
The physicist Enrico Fermi, in response to a sufficiently high estimate of the chances of interplanetary contact by Drake’s formula, formulated a thesis now known as the Fermi paradox: if there are so many alien extraterrestrials, why does humanity not observe any of their tracks?
This paradox scientists have tried to solve in many ways, the most popular of which is the hypothesis of the “unique Earth”. It says that for the emergence of intelligent beings, unique conditions are necessary, in fact, a complete copy of our planet. Other astronomers believe that we can not communicate with aliens because the galactic civilizations either disappear too fast for us to notice them, or because they actively hide the fact of their existence from humanity.
Stern proposed his own explanation of this phenomenon, which does not require the existence of galactic “camarillas” of rational races or justifications for the uniqueness of the Earth.
Studying the lists of newly discovered exoplanets that are inside the “life zone”, a special area of the orbit where water can exist in liquid form, the planetologist from NASA drew attention to the fact that many planets, similar in size to the Earth, are not stony celestial bodies, but oceanic worlds. They can be either completely covered with liquid water or the ice crust under which the icy ocean lies, similar to those found on satellites of Saturn and Jupiter.
This observation made him think about how often life can arise on such planets, which will influence the probability of its origin and how such water forms of life can establish contact with mankind.
As his calculations showed, such oceans, covered with a thick crust of ice, should be much more friendly for the birth and development of life than the “open” planets, similar to the Earth. As Stern believes, if extraterrestrial life exists, then it most likely lives in the depths of such water worlds.
“The inhabitants of such worlds will not even suspect that there are stars, cosmos and other planets in the Universe, the closest equivalent of our space program will be the access to the surface of their water world, so neither we nor they will suspect about the existence of each other, – concludes the scientist.