Are there any other living creatures in the Universe besides us, has anyone achieved the same level of civilization or a more intriguing question - has anyone forestalled us to such an extent that one can quietly fly to us, watch us and even influence events on Earth? What can be said by virtue of the scientific data available about the possibility of life in other worlds - about the existence of extra-terrestrial intelligence (the SETI¹ problem)?

We know for a fact that life in its simplest form appeared on Earth actually immediately after conditions had arisen for it on our planet - moderate temperature on the surface, water and atmosphere; all this happened close to 4 billion years ago. One of intriguing moments is the very moment of the birth of living organisms from inorganic, inanimate matter that can reproduce themselves, give birth to offspring, and gradually alter their structure. Most popular versions so far are the effect of meteorites with organic molecules getting to the planet surface or the origination of simplest organisms near volcanoes and under the influence of electric discharges.

On each of the hypotheses the initial "act of creation" could occur by no means on the Earth, - but rather on any body in the huge Universe. The volume, amount of the matter of the Universe are so great that the probability of favorable conditions for the advent of life surpasses the possibilities of our planet many billions (even billions of billions) times². Part of numerous stars in the Universe (possibly a third) may have satellites - cold planets revolving about them. The likelihood of the conditions to arise that may involve the advent of life, that is, simplest organisms capable of multiplying, is enhanced by many an order compared to the possibilities on Earth. Further, with the emergence of a substance (organic or, not improbable, any other)in any place in the Universe, with the propensity to multiply, it is easy to conceive its distribution (panspermatism or panspermism) on meteorites, comets and fine particles (star dust) moving in outer space. It has been closely established to-date that the fragments of matter - meteorites, etc. falling on the Earth often carry the fragments of organic molecules. Having found themselves in a favorable medium, they can become the embryos of the simplest organisms and, in particular, to initiate the onset of future evolution. It seems that asteroids and other celestial bodies travel in the Universe millions and billions of years, thus preserving the embryos of life that can turn into living organisms under favorable conditions.

The advent of life in the form of simplest creatures is followed by evolution of the latter - prolonged modifications, complication, adaptation to the environment - right up to multi-cellular complex organisms (Metazoa) and, eventually, as the crown of creation (in today's understanding) the appearance of conscious creatures - homo sapiens.

It has already been established today that violent catastrophes periodically happened on the Earth. At times up to 70-90% of living and plant organisms died out, but subsequently, those survived got adapted, altered, and new species acquired different, better qualities (for the survival and emergence of offspring) and often more complex organization. One succeeds in tracing the evolution of multi-cellular organisms and building a plausible true scheme of their variations - the tree of life.

At the end of the 20^th and beginning of the 21^st centuries many new factors have been obtained that contribute to understanding the advent and spreading of life. As was noted, organic molecules were found on some asteroids that fall on the Earth; Having found themselves on Earth in a favorable medium, these molecules triggered the evolution of living organisms. Another event that shocked scientists is the presence of planets in stellar systems located far from us. Beginning with the first³, approximately twenty new exo-planets are discovered every year. In all there are about 400 distant planets are registered today.В  They are largely the size close to Jupiter, but lately there have appeared means of observation capable of detecting objects the size of Earth. In March of 2009 the Kepler laboratory-telescope was put into the Earth's orbit alongside other devices which within three and a half years are to study around 100,000 stellar systems in our Galaxy with an eye to locating planets therein the size close to that of the Earth. It is assumed that close to 50 may be found, as well as 600 twice as large. So the information related to the problem under discussion is likely to grow in an avalanche.

It is logically inferred that conditions on the surface of a number of discovered planets may be acceptable for the development and evolution of life. These conditions may be suitable also in a more distant cosmos - on planets that are satellites of numerous distant stars of the Universe that are more difficult to observe.

Today there is the following version of the origin of sophisticated forms of life. The planets that have conditions for the existence of protein bodies are "impregnated" by asteroids or other space material falling on them. Then, comes the evolution and complication of organisms and given the scenario which occurred on the Earth, we see that this complication may bring about over billions of years the emergence of intelligence, intellect in one of the species. It may lead to what we observe now on the Earth - a civilized community that fully harnessed our planet.

(It is natural to assume that the evolution on other planets suitable for life might begin billions of years later or earlier than on the Earth: plentiful stars and accumulations of substance that we observe are at most different stages of the transformation of matter).

Our highly developed civilization has been in existence for some 100 years out of 4 billion, i.e., about 10 ^-5 % out of the total time of evolution. It is precisely in this period that information is generated from the Earth in the form of radio signals, nuclear explosions in the atmosphere, TV and, at times, laser radiation which other civilizations might have noticed. Today we might discover other civilizations with the aid of modern radio telescopes, computers and other equipment capable of trapping and analyzing signals from space. But, unfortunately, now we face not very favorable attributes of our highly advanced civilization, namely, means of mass destruction - nuclear, chemical and biological weapons that have come into being over the same hundred years and in such amounts that they can completely ravage our planet. It is not ruled out that other means of destruction will appear in the near future based on nanotechnology, genetic engineering, robotics or other new fields of science.

Further, a more important sacramental question arises: how long will the advanced civilization with weapons of self-annihilation exist? Will it use them as it did before with other weapons at all stages of drive for the means of existence and territory to dominate over others? At all stages of our history (and long evolution) the strongest (and in recent period better armed), even more aggressive and cruel turned out victorious and conquered others. What may happen now when a war or large armed conflict will most likely lead to total collapse?

If intelligent societies destroy themselves at a certain stage of evolution and the period of their existence and the time when they can send a signal and receive it from others are infinitesimal (for mankind it is of the order of 10 ^-5 % of the total time of the evolution of life - see above), the signals to each other most likely do not coincide in time, to say nothing about their attenuation due to considerable distances.

Thus, the analysis of two problems - "the threat of self-annihilation of civilization” and "why the Universe is silent" brings about the following version:

1. The time of the existence of highly-advanced civilizations (may be our civilization as well) is rather limited and
2. Signals from such civilizations (information about them) are, as a rule, not received by other planets because they are too short-lived and do not coincide in time⁴. If this is the case, it is clear why we fail to see or hear anyone: civilizations cease to exist soon after they start generating information outside.

Finally, we draw a rather essential conclusion: one can ensure a sustainable development only by radically changing the system of behavior, methods of settling conflicts in human society - for example, by accomplishing the scenarios described in the book "Civilization in the 21^st Century. In this case, the Earth would evolve along a new path, possibly rare in other worlds.

In summary - some optimism. Of course, given a large number of inhabited planets in the Universe there is a chance that certain advanced civilizations do succeed in settling their internal discords peacefully andl exist for a long time. Then it is more probable they detect each other, maybe even for the exchange of information, collaboration in cognizing and assimilating the Universe.

See illustrations at - http://www.youtube.com/watch?v=BwzXE__fsJE

_________________________________________________________________

Notes

1.SETI - Search for Extra-Terrestrial Intelligence

2.Reasoning from our conventional life experience it is difficult for us to conceive such big numbers. In general, in studying the Nature we more often face unusual notions, scales and digits. The knowledge to manipulate them, analyze the new unknown objects allows studying the world in greater detail and in many cases taking a more correct pattern of behavior. In the current century this may relate to the problem of the preservation of life on the Earth.

3.The planet called Bellerophon, discovered in 1994 (1995?), has the mass 150 times greater than that of the Earth and revolves around the star 51 (reads as "fifty first") Pegasi, barely perceptible by the unaided eye. The distance from the Earth is 50 light years.

4.One may raise a question how to combine the notions about a short-term existence of civilizations and billion-year long travels of the embryos of organic molecules on asteroids. The answer is simple: the molecules are not that clever so as to be able to destroy the medium where they dwell.