1 Astrobiology and SETI: the possible solution of the Fermi paradox Aleksandr V. Bukalov The Centre of Physical and Space Researches, IIS, Melnikova str., 12, Kiev-050, 04050, Ukraine e-mail: boukalov@gmail.com Basing on the new physical approach in description of the characteristics of live matter, the author obtained a numerical values for mass of living matter in the Universe, quantity of biospheres in the Universe (N bio ~3.3·10 18 ), quantity of biospheres in the Galaxy (N~5·10 7 ). The calculated average distance between biospheres in the Galaxy is l ≤ 40 light years. However, the probability of disclosure of an extra- terrestrial civilization, analogous to Earth one, is too small, P~10 -5 . It is shown, that a paradigm of the expansive and extensive development of the modern technological civilization in the bounds of SETI is useless principally, as for planetary civilization exist demographic, power, destructive and genetic-adaptive natural barriers, and limits of continuous growth and cosmic expansion. A strategy of intensive growth of civilization using the low-energy quantum technologies is more realistic. In that case, the radiation of civilization becomes low and it is very difficult to detect such civilization in the electromagnetic diapason. It is the possible solution of astro-sociological Fermi paradox. Key words: SETI, quantity of biospheres in the Universe, life in Galaxy, strategy of the civilization growth, astrobiology, communication, thermodynamics. PACS: 87.10.-e, 96.55.+z 1. Introduction The determination of the inhabited planets quantity is rather complex problem today. The detection of the gigantic clouds with organic molecules in the Galaxy points out that in Cosmos there are natural resources for the alive matter creation (nuclein and aminoacids) under the suitable conditions on certain planets. Recent investigations of the Mars meteorites provide us to make a conclusion about the existence of some life forms on this planet. This conclusion is supported by the known fact of the existence on Mars of the dryed rivers beds. Besides, recent investigations provided the detection of the freezed water under the Mars surface. The organic molecules were detected in the comet matter, which also can be treated as concentrators of organics and the primary reactions of the organic molecules synthesis, especially under the drawing near the Sun and other analogous stars. The last 20 years investigations showed that some alive microorganisms are extremely proof against the action of unfavorable factors and are able to survive in the space vacuum conditions. 2. The quantity of biospheres in the Universe The mentioned facts totality proves us to make a conclusion that the life was not sure born on Earth (or even on Mars) but populated the Earth when the suitable conditions was risen on the planet after cooling. Thus the Earth biosphere is not a unique one and the only in the Galaxy and Universe. Then the regular question arises: what is the quantity of inhabited planets? Till the lately time it