If life can occur in one place in the universe, then there is a high possibility that it's occurred somewhere else-even if we don't know about it. Life on other planets would only be an impossibility if the universe was devoid of life altogether, i.e. if we didn't exist-we are proof of alien life! COnsider the number of galaxies, and the number of solar systems in those galaxies-it is a mathematical certainty that E.T. is out there-but not in the form we expect.