Enthusiastic and charismatic scientist well known for its popularizing works on space sciences, Hubert Reeves said in #666 of the French magazine of scientific popularization "Sciences et Avenir," in August 2002:
Why can life exist only on planets identical to the Earth?
"Nothing is less certain! One of the fundamental discoveries of these ten last years is that life is much more robust than it was thought. Previously, it was imagined that life exist only within very narrow physical limits. Since then, life was observed in acidic media, with practically negative PH, as well as in very basic environments. It proliferates in very salty waters, in brackish muds, in the ices of the South Pole, at temperatures of 110°C, without light. Bacteria resist radiations which would kill anybody among us 50000 times. That life is more resistant than previously thought raises questions. Nowadays, one is much less categorical, the discovery of our ignorance inclines us to be more modest. It is said that perhaps there is still dormant life on Mars, since certain bacteria seem to be able to hibernate during milion years. Nobody dares to say that life can appear only appear on twin sister of the Earth anymore."
Source: http://www.sciencesetavenir.com/encouv/p666/a23218.html Thanks to this site's visitor Yves who shown this article to me.
During a series of conferences in 2000, such the one given October 17 at the Marie-Gérin-Lajoie Room of the Quebec University in Montreal, Hubert Reeves explained:
"One could think that there are perhaps other civilizations on other planets. This is only within the range of the possible and not a certainty, but suppose another planet than the Earth where life appears and develops. There is a fundamental phenomenon of life on Earth which is competition, i.e. the living beings must eat and risk to be eaten in their turn. Within the framework of the biological studies by Darwin, one sees very well that the growth of complexity, i.e. biological evolution, is centered much around these phenomena of competition, of struggle for survival. In this struggle, the favoured beings are those who have certain advantages. It can be long teeth or claws, but, for the human beings, the advantage which enabled us not only to survive but to threaten all the other animal species, is intelligence. The intelligence develops science, which one day or the other develops industry, nuclear energy... One can think that what occurs on our premises probably happened or will more or less happen on any inhabited planet. Once again, it is only an assumption but it is a plausible assumption. If this is the case and if the logistics of life is systematically accompanied by the appararition of intelligence and the works of that intelligence (technology, industrialization...) one can think that we are not the only one in this situation."
