We will, no doubt, never know.  Many eminent scientists have long been convinced that it is, to use an astronomical understatement, highly improbable, that among the billions of galaxies, each with a hundred billions stars and the ten billion billions of planets that make up the Universe, there is only one, tiny, insignificant planet – ours – which has intelligent life.  Some of these same scientists, fifty years ago, at the time of the launching of Pioneer 10 and 11, fearing that there is, in fact, such life out there, opposed the sending into space of Carl Sagan’s famous golden plaque, designed and destined to introduce us to potential extra-terrestrials, because this, they felt, would allow the latter to identify our location in the cosmos and to . . . attack us !  Orson Welles redivivus : “Mars Attacks !”, the famous radio hoax which caused uncontrolable panic in the U.S.  The message of the fearful scientists was similar to that of Descartes, centuries before, who however had far more down-to-earth motivations : “Qui bene vixit, bene latuit” (“He who has lived well has lived well-hidden”).  Let’s keep our existence secret; it’s safer.  Today well-heeled celebrities do not have accessible phone-numbers, e-mail or snail-mail addresses available to their cohabitants of Planet Earth.  At the time of the Pioneers, some did not want even our situation in the Universe to be known to outsiders.

One thing of which we can be certain is that whether or not there are little green people out there, there is no God, no Creator of the Universe, no Intelligent Divine Designer, just stupid evolution which may or may not have produced life elsewhere.  Personally, I am not sure I would count on our possible galactic neighbors to help us solve our existential and ecological problems.  They and we should stay at home, minding our own terrestrial or extra-terrestrial business.

Whether we are alone or not, we will continue, “sine die”, to live as though we were.