Living organisms which exist on earth are open self-regulating and self-replicating systems. Their most important functional components are biopolymers, namely, proteins and nucleic acids. Quite general scientific considerations indicate that life ought to exist beyond the limits of the earth, somewhere in the universe, if not on other planets of the solar system. At present, we know only organisms which exist on earth; reports on the finding of microorganisms in meteorites have not been confirmed up to now.