Number of fundamental questions have not yet found the definitive answer. However, the scientific community pursues its efforts with a will stronger than ever.

The quest of our previous history and that of our future is launched. When we will discover our original ancestor LUCA, we will only have questions about ou future. The search of our past will not indeed supply us with any answer, and maybe science will try to foresee future by discovering former worlds that has been able in the past to shelter an evolved form of life.

But if we find a form of life similar to our bacterium, can we say that it will have repercussions except the scientific circle? It hardly has to bet there that event would make it one of newspapers and that the earthly population would assimilate information to its usual speed no more to worry about it.

On the other hand, which would be the reaction of the humanity to the reception of a signal (radio or optics) that one would establish clearly as being of extraterrestrial essence? It is maybe in that case of figure that would be left fields free with philosophic and theological debates, relèguant scientific argumentation in the background by showing her its limits: the elaboration of hypotheses in front of speculations of the people...