Flashmag Digizine Edition Issue 107 July 2020 - Page 184


Flashmag July 2020 www.flashmag.net

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We can also establish an approximate number of this number, if we consider that there are certainly 100 billion "lands" in the Milky Way: we can count 1022 planets, the size of Earth, roughly speaking, in the whole Universe! Naturally, we can also say that chances for life to exist there seem innumerable, which would confirm the luck of researchers to discover a planet where life could develop… and worse if we talk beyond the universe henceforth of the multiverse, the theory which admits the existence of several universes we have no number in mind, if not infinity.

Nowadays, however, if researchers have discovered suns similar to ours (which is essential to hope that life can exist on a planet) ... they have not found a solar system similar to ours, despite decades of uninterrupted work on the whole Earth!

We are therefore at a turning point in our vision of the Universe, as the astronomer Franck SELSIS, of the Laboratory of Astrophysics of Bordeaux states: "The planetary systems that we have been discovering for a dozen years present an astonishing diversity, facing this reality, our solar system will soon be exceptional! "

Indeed, our solar system is perfectly known, and designed in a very favorable way for conditions suitable for life on earth: with small rocky planets grouped all around their star, then gaseous more distant . A whole theory concerning their creation had been exactly established, and served as a model ... but! Among all the "suns" examined, only planets of great diversity were found. The solar system appears to be entirely atypical and exceptional; computer simulations have established the existence of at least a hundred different planetary systems. Astronomers then demonstrated that the formation of a system comparable to ours, where the rocky planets and gas giant planets rotate in almost circular orbits (which requires extremely precise initial conditions) is extremely rare. Their cautious but clear conclusion is: "... in all of the planetary systems of the Universe, those that resemble ours are the exception rather than the rule. "

New logics are proposed in front of so many unexpected facts, and it is humbly that all our knowledge is forced to these inevitable revisions. Of course, exobiologists therefore know more precisely what to look for, but at the same time they discover the enormous additional difficulties that await them until they find a solar system corresponding to our own.

Years ago, for example, they discovered a rocky exo-planet much like Earth, called MOA-2007-BLG-192Lb, which sparked new hope. But they noticed that it revolves around a small red star very different from our Sun, and that there must therefore a temperature below -220 ° C reigning there…