Huge, amazing spaceship run for several miles hanging right above Los Angeles; he fills the sky and gives birth in the city ominous darkness. Fortress in the form saucers take positions at key points above the planet - above the main cities of the world. Hundreds of jubilant spectators gather on the roof of a skyscraper, closer to the star guests; earthlings want to be the first to welcome the alien visitors in Los Angeles.

Has sagged silently over the city for a few days, life slowly reveals the belly. Shoots out a sheaf applause laser beams. The burnt skyscraper; the city was a wave of destruction, for a few seconds, turning it into a pile of charred debris.

In the movie "independence Day" aliens represent our most deeply hidden fears. In the movie "ET" we project on the same alien own dreams and fantasies. Throughout the history of mankind would not let the thought of alien creatures that inhabit the other worlds. In 1611, the astronomer Johannes Kepler, relying on the most advanced scientific knowledge of that time, talked in his Sleep on the journey to the moon. He wrote that during this trip people can meet intelligent aliens and alien plants and animals. But science and religion often contradict each other about life in space, and the result of this contradiction sometimes ends up in tragedy.

A few years earlier, in 1600, in Rome was burned alive in the former Dominican monk and the philosopher Giordano Bruno. To humiliate Bruno, the clergy, before you burn at the stake, they stripped him naked and hung upside down. What did the teachings of Bruno so dangerous? He asked a simple question: is there life beyond Earth? Like Copernicus, Bruno was convinced that the Earth goes around the Sun, but unlike Copernicus he felt that there, in space, lives, perhaps countless others like us. (The Church decided that it is easier and more convenient to burn the author insane idea, than to think seriously about the possible existence of billions of other saints, popes, churches and Jesuses.)

Four hundred years the memory of Bruno was not allowed to live in peace historians of science. But now Bruno avenged. About twice a month astronomers find in space about some star new planet. At the moment it is known about the existence of various stars of about 300 planets, so the prediction of Bruno in respect of extrasolar planets has come true. But one question still remains unanswered. Maybe the milky Way galaxy jam-Packed full of planets, but how many of them are suitable for life? And if in space really there is intelligent life, what can science to say about it?

Of course, hypothetical meeting with aliens cause in society fervent interest, fascinate many generations of readers and viewers. The most famous incident occurred on October 30, 1938, in Halloween; then actor and Director Orson Welles decided to make fun of the American public. He had based the novel by H. G. wells ' war of the worlds" and prepared a series of short allegedly news. These messages were transmitted in the broadcast of the national radio company of CBS, interrupting dance music and hour after hour reproducing the script invading Martians Land and the subsequent collapse of civilization. Millions of Americans hit the panic from the "news" that in Grovers mill, new Jersey, landed machine from Mars that they shoot deadly rays, destroy entire cities and are going to take over the world. (Later the Newspapers wrote that in the area began a spontaneous evacuation of residents tried to leave it; there were eyewitnesses who claimed that smell in the air poisonous gas and I see flashes of light in the distance.)

In the 1950s interest to Mars rose again; in fact, astronomers discovered on Mars strange mark resembling a giant letter M in the amount of several hundred kilometers. Then in came comments: the letter M sure means Mars is a peaceful Martians serves earthlings signal, like a stadium during a football match support group to spell out the name of your favorite team. (Other ominous objected: actually, the grade is the letter W, not M, and W means, of course, the war. In other words, actually Martians announce the Ground war!) Arising mini-panic soon subsided, and the mysterious letter M has disappeared as suddenly as they appeared. Apparently, the illusion was caused by sand storm that covered the whole surface of the planet, but the tops of four major volcanoes. These four peak and has developed in crude form the letter M or W
The scientific search for extraterrestrial life

Serious scientists engaged in the search of possible extraterrestrial life, say about this life - if it exists - it is impossible to say anything definite. However, based on our knowledge of physics, chemistry and biology, you can make a few General assumptions about the nature of extraterrestrial life.

First. Scientists believe that the key factor for the emergence of life in the universe is liquid water. "Seek water is a mantra repeated astronomers, looking for evidence of the existence of extraterrestrial life. Liquid water, unlike most other liquids, is the "universal solvent" and capable of dissolving a striking number of various chemicals. This is an ideal environment for the emergence of more complex molecules. In addition, a molecule of water is very simple, it can be found everywhere in the Universe, while others solvents are rare.

A second. We know that carbon is very likely component life. The fact that the carbon atom tetravalent, and thus can communicate with up to four other atoms, creating a molecule incredible complexity. In particular, it easily forms long carbon chains - the main element of hydrocarbon compounds and all organic chemistry. Other tetravalent elements of a number of possible chemical compounds not so rich.

A graphic illustration of the indispensability and the importance of carbon can serve as the famous experiment of Stanley Miller and Harold Urey, held in 1953 Experiment showed that life is, in principle, can occur spontaneously as a natural side effect of chemical processes with participation of carbon. The scientists took the solution of ammonia, methane and other toxic substances - those who, in their opinion, should have been present on Earth in its initial epoch, is placed in a closed vessel and exposed a weak electric current. After that, I could only wait. After a week in a vessel showing signs of spontaneous formation of amino acids. Electric current was enough to break the links in ammonia and methane, and then rebuild the atoms in the molecules of amino acid precursor protein. In a sense, life really can occur spontaneously! (Later amino acids were found in the composition of meteorites and gas clouds in the depths of space.)

Third. The basis of life - can replicate themselves a molecule called DNA. In chemistry replicating molecules are extremely rare. It took hundreds of millions of years, on the Earth, most likely in the depths of the oceans, formed the first DNA molecule. It is believed that, if we could conduct an experiment Miller-Urey length in a million years in the amount of the earth's oceans, the DNA molecules could be spontaneously appear. One of the most likely areas where in the beginning of earth's history could accidentally be the first on the planet, the DNA molecule is designated volcanic outputs on the bottom of the ocean, the so-called "black smokers". The activity of these hot springs could serve as a convenient source of energy for the first DNA molecules and the first cells - long before the appearance of photosynthesis and plant. We still unknown others, in addition to DNA, carbon-containing molecules that can replicate themselves, but rather, all other replicating molecules in the Universe will be something similar to the DNA molecule.

To summarize. For life, apparently required liquid water, hydrocarbon compounds and some form of self-replicating molecules like DNA. Using these fairly common criteria, we can estimate the frequency with which it occurs in the Universe is intelligent life. One of the first such evaluation was conducted by Cornell University astronomer Frank Drake in 1961, If you take 100 billion stars in the milky Way galaxy, you can estimate what proportion among them are the stars with the same characteristics as our Sun. You can then estimate the share of suitable stars, near which is the planetary system.

More specifically, the Drake equation allows to calculate the number of civilizations in the Galaxy by multiplying several variables, including:

• speed of birth of stars in the Galaxy;

• the fraction of stars that have planets;

• the number of planets suitable for life conditions near each star;

• the fraction of planets on which actually occurs life;

• the share of the planets, where they develop intelligent life;

• the share of the planets, a civilization which is able and want to communicate with other civilizations;

• life expectancy civilization.

Based on reasonable estimates and multiplying all of these can be mostin particular, we will see that in only one of the milky Way galaxy may be from 100 to 10 000 planets that have a reasonable life. If intelligent life forms evenly distributed across the Galaxy, it can be expected that one of such planets may be found to be "close" - just a few hundred light years from our Solar system. In 1974 Carl Sagan made another assessment; in his opinion, in our galaxy the milky Way may be up to a million of civilizations.

These theoretical arguments, of course, have given additional arguments of those who try to detect the signs of the existence of extraterrestrial civilizations. Optimistic estimates of the number of stars in the Galaxy, suitable for intelligent life, gave scientists the opportunity to begin a serious search for radio signals from outside; speech in this case goes about the signals that can radiate planet with a developed civilization - like television and radio signals, which are actively radiate our own planet last 50 years.
Listening to aliens

The project of the search for extraterrestrial intelligence SETI originates from the article, written in 1959 physicists Giuseppe Kokk?nion and Philip Morrison. This article made a strong effect. The authors suggested that catching signals from extraterrestrial civilizations better on radio-frequency from 1 to 10 GHz. (Signals with a frequency below one gigahertz mutes the radiation of fast-moving electrons, and at frequencies above ten gigahertz any signal will have a strong distortion due to the noise, which emit oxygen molecules and the water in our own atmosphere.) The most promising they found that the frequency of 1420 MHz - frequency radiation of ordinary hydrogen, the most abundant element in the Universe; they proposed to start the search for signals from outer space it is at this frequency. [Frequencies close to this value, convenient for extraterrestrial communication, known as the "water box".)

However, the search for intelligent signals near the window, in what have not resulted. In 1960, Frank Drake has initiated the project "Ozma" (named after the Queen of Oz); signals were supposed to be searched using a 25-meter radio telescope in green Bank, West Virginia. Reasonable signals could not find anyone, in the framework of the project "Ozma", nor under any other of the many projects that over the years there have begun to scan the night sky.

In 1971, NASA proposed to undertake the financing of the SETI project. This project, also known as project "Cyclops", involved the use of a thousand radio telescopes and was supposed to cost $ 10 billion. No wonder it over a zilch. Financing still managed to get, but for a much more modest project - send into space carefully encrypted message to other civilizations. In 1974, a message containing 1679 bit, was sent with a giant radio telescope in Arecibo in Puerto Rico in the direction of the globular cluster M13, located at a distance of 25 to 100 light-years from us. This little message is a picture size : 23 x 73 points; scientists have identified it the position of the Solar system, put the image of human beings and several chemical formulas. (Considering the distance in question, the answer can be expected not earlier than 52 166 years.)

The U.S. Congress all these projects have made not too impressive, even when, in 1977, was registered signal, known in history under the name of "Bay". It was possible to see a sequence of letters and numbers, which seemed not random and spoke like about the presence of extraterrestrial intelligence. (Admittedly, not all scientists who had seen the signal "Bay"were confident in its non-random.)

V the American astronomers have lost hope of funding from the Federal government and decided to turn to the private funds. Was founded non-profit SETI Institute in mountain view, California, and launched the project "Phoenix"; the project studies thousands nearest stars solar class of radio-1200-3000 MHz. Director of the Institute chose Dr. Jill Tarter, which was the prototype of the character jodie foster in the movie "Contact". (In this project are extremely sensitive devices that can detect radiation regular aerodrome radar from a distance of 200 light years.)

Since 1995, the SETI Institute, with a budget of 5 million. a year already scanned more than a thousand stars. But tangible results still there. However, Seth Shostak, senior astronomer at the SETI project, with unfailing optimism believes that the System of telescopes Allen part 350 antenna, which is now under construction in 400 km to the North-East from San Francisco "will find the signal before 2025".

A novel approach to the problem demonstrated astronomers from the University of California at Berkeley; in 1999, they launched the SETI@home project. The idea of the project is to attract the millions of owners of personal computers, whose cars most of the time simply do nothing. Those involved in the project, downloaded from the Internet and install on your computer a software package that operate in a screensaver, and therefore do not deliver to the owner any inconvenience. These programs involved in decoding of the signals received by the telescope. Until now joined the project 5 million users from over 200 countries of the world; together, they spent electricity more than a billion dollars, but each user participation in the project cost is inexpensive. This is the most large-scale collective computer project in the history; it could serve as a model for other projects that require large computing power. However, so far the SETI@home project also found no reasonable signal.

The blatant lack of results after several decades of hard work forces supporters of an active search for extraterrestrial intelligence to find answers to difficult questions. One of the obvious shortcomings of the project can be demonstrated by the fact that the search is only at certain frequencies of the radio spectrum. There are suggestions that other civilizations instead of radio signals using a laser. Compared with the radio lasers have several benefits; thus, the shorter the wavelength means that the signal can carry more information. But the laser signal is a thin beam on one strictly a given frequency, so it is extremely difficult to detect and register.

Another disadvantage, obviously, it may be the wrong choice of radio bands. Extraterrestrial civilizations, if they exist, can use a variety of compression methods, or, say, to break messages into small packages, as it is done today in the Internet. It may well be that, listening to compressed messages, distributed in addition to several frequency bands, we will hear only white noise".

But even with all the very serious problems facing SETI, it is reasonable to assume that in this century we will be able to register signals of extraterrestrial civilizations - provided, of course, that such civilizations exist. And this event, if happens, will be a turning point in the history of the human race.
Where are they?

The fact that SETI not found so far no signs of presence in space of signals from other intelligent beings, forced scientists to look more closely at the assumptions that underpin the Drake equation for intelligent life on other planets. The latest astronomical discoveries suggest that our chances to find in space intelligent life are very different from those calculated by Frank Drake in 60-s of the last century. The likelihood of intelligent life in the Universe there is both more and less than previously thought.

First, new studies show that life can exist in such conditions, which are not envisaged by any equations Drake. Before, scientists believed that liquid water can exist only at a certain optimal distance from the star, in the "zone of life" (Land is the "most suitable" distance from the Sun. Not too close or the oceans just boils, and not too far - otherwise the oceans will freeze; no, the distance from the earth to the Sun is optimal for life.)

Therefore, scientists have got a real shock when astronomers have found evidence that liquid water may exist under the icy crust of Europa, a moon of Jupiter. Europe is far beyond the "zone of life" and at first glance does not satisfy the conditions of the Drake equation. However, it tidal forces act, which may be enough to melt the ice cover of the satellite and form in Europe permanent liquid ocean. Europe turns around Jupiter, and the tremendous gravitational field of the planet shrinks satellite, like a rubber ball, creates tension and friction deep in the crust, and this in turn can cause the melting ice. Only in our Solar system more hundreds of satellites; this means that it outside the "zone of life"may be many moons with livable conditions. (And 300 famous giant planets in other solar systems can also be frozen moon suitable for life.)

Moreover, scientists believe that the Universe is quite possible, there are many wandering planets that do not address more around its star. Due to the tidal forces of any such satellite wandering planet may have under the crust of ice liquid oceans, and therefore life. But such planets (and, naturally, their satellites) cannot be detected by our instruments, because we are in their search based on the light of the Central star.

Given the fact that the number of moons in any solar system, likely far exceeds the number of planets, and also taking into account the likely presence in the Galaxy millions of wandering planets, the number astronomical bodies with those or other forms of life in the Universe may be much greater than previously thought.

However, other astronomers based on a variety of factors, conclude that the chances of life on planets within the "zone of life", should be probably much lower than estimated Drake.

Firstly, computer calculations show that for existence in the solar system, life requires the presence in it of the planet-giants like Jupiter (this planet will discard flying comets and asteroids, constantly clearing away space of your system). If our Solar system were not of Jupiter, the Earth is constantly bombarded would meteorites and comets, and life on our planet would not be possible. According to the assessment of Dr. George Wetherill, an astronomer at the Carnegie Institution in Washington, don't be in the Solar system, Jupiter and Saturn, the Earth would be a thousand times more collisions with asteroids and terrible catastrophes that threaten the life on the planet (like the one that 65 million years ago killed the dinosaurs)that would occur every 10,000 years. "It is difficult to imagine how life could survive in such conditions," says Wetherill.

Secondly, our planet is more treasure is a great companion that helps to stabilize its rotation. Scientists have created a gravity model (based on the laws of gravitation of Newton) and calculated the motion of bodies on the millions of years, has turned out, that without the moon the earth's axial tilt, probably, would not be permanent, and the planet could even turn over. The life of this would have been impossible. According to estimates by French astronomer Dr. Jacques Lasker, without the moon, the tilt of earth's axis would fluctuate in the range from 0 to 54 Degrees; the consequence of this would be extreme climate variability incompatible with life. Thus, the existence of the planet's large satellite should also be considered necessary for life to the terms that appear in the Drake equation. (The fact that Mars has only two tiny satellites, too small for stabilization of rotation means that in the past the Red planet may have fallen and can again to turn over in the future.)

Third, the newly-acquired geological data indicate that in the past life on Earth many times was on the verge of extinction. About two billion years ago the Earth, probably, was completely ice-covered; life on it hardly glimmered. At other times to put the life on the planet to the brink of extinction could, for example, volcanic eruptions or the impact of large meteorites. So, the process of origin and development of life can easily be broken off; it is much more fragile and vulnerable, than it seemed to us previously.

Fourth, intelligent life on Earth in the past has repeatedly appeared on the verge of extinction. About 100 000 years ago on the planet, according to the latest studies of DNA, lived only from a few hundred to several thousand people. Unlike most animals, which even within the same species have significant genetic differences, human beings are genetically almost identical. In comparison with the animal Kingdom, we almost all clones of each other. This phenomenon can be explained only by the fact that in the history of mankind were bottlenecks, i.e. the times when nearly the entire human race has been erased from the face of the Earth. For example, a major eruption of the volcano could cause a sharp cooling of the climate, and to destroy thus almost all mankind.

You can mention other favorable chance, without which life on Earth would not have arisen. Among them:

• Strong magnetic field. It is necessary for protection against cosmic rays and radiation, capable of destroying all life on Earth.

• Moderate speed. If the Earth rotated slowly, sunward side had sufficient time to fade, while the other side would freeze up for a long time. If the Earth rotated too fast, the weather would be extremely unstable, constantly Dooley would be terrible winds and raging storms.

• Location at the optimal distance from the center of the Galaxy. If the Earth were located too close to the center of the milky Way galaxy, it was always a hit hazardous radiation. If our planet was too far from the center of the Galaxy, there has not been a sufficient amount of heavy elements for the emergence of DNA molecules and proteins.

Given all this, astronomers currently believe that life might exist outside the "zone of life", on the satellites of the planets or wandering planets, but the chances of the existence of habitable earth-like planets within this zone considerably lower than previously thought. In General, most researchers equations Drake agree that the chance to discover a civilization in the Galaxy, probably lower than assumed himself Drake.

Professors Peter ward and Donald however say: "We believe that life in the form of microbes and similar creatures are quite common in the Universe, perhaps even more common than believed Drake and Sagan. However, complex life - animals and higher plants - meets probably much less common than it used to be". In fact ward and however even admit the possibility that the Earth is the only planet in the Galaxy where there is animal life. (Of course, this theory may ruin in the Bud all the search for intelligent life in our Galaxy, but the question of the existence of life in other, distant galaxies, it still leaves open.)
The search for earth-planets

Drake's equation, of course, is purely hypothetical. That is why the detected outside the Solar system planets gave impetus to the search for extraterrestrial life. Thus the study of planets in other solar systems is strongly complicated by the fact that the planet cannot be seen even in the most powerful telescope because it neither emits its own light. As a rule, a planet in a million or a billion times dimmer its star.

To detect in other star systems of the planet, scientists have to analyze tiny fluctuations of the Central star is in fact already planet-giant like Jupiter quite able to change the orbit of the stars. (Imagine a dog that chases its own tail. Similarly, the star and traded around her planet the size of Jupiter actually "running" each other around a common center of mass. The telescope is not able to see the dark planet, but the Central star system is clear and varies considerably from side to side.)

The first reliable extrasolar planet discovered in 1994, Alexander Volcan from the University of Pennsylvania. He was able to observe planets revolving around a dead star, rotating pulsar. Since the Central star of this system, apparently, when something exploded as a supernova, these planets also likely burned and dead. Next year two Swiss astronomer from Geneva, Michel Mayor and Didier Kelo, announced that they have found more promising planet with a mass about Jupiter around the star 51 Pegasi. Soon after the dam burst," and exoplanets began to appear one after the other.

In the last ten years the number of planets that astronomers find annually near distant stars, is growing rapidly. Geologist Bruce Jakosky from the University of Colorado at boulder says: "it is a special period in the history of mankind. We are the first generation that has a real chance to find life on another planet."

But none of the detected so far solar systems similar to our own. Once astronomers believed that the Solar system is a typical and that such systems are often found in the Universe. Its main features - circular orbits of the planets and a clear division of planets into three types: stone planet near the Central star, next gas giants and, finally, comet belt of flying ice mountains.

But astronomers, to his great surprise, found that none of the planets in other systems does not meet this simple scheme. In particular, the giant planets like Jupiter, it would seem, should be placed far from the Central star; in fact, many of them visit or very close to the star's orbit (even closer than mercury in the Solar system), or greatly extended. In any of these cases, the existence of small terrestrial planets within the "zone of life" may not count. If the planet class of Jupiter turns on very close to the star's orbit, which means that it migrated there from distant orbits and now spiral is near the center of their system (probably, it gradually slows down the dust). At some point this giant planet had to cross the orbit of the small planet of the earth type; while a smaller planet would be thrown into the depths of space. If a planet the size of Jupiter revolves around a star on a highly eccentric orbit, which means that it regularly cross the "zone of life", again discards away from the star met any planet of the earth type.

These results, of course, disappointed hunters planets and astronomers, counting on terrestrial planets, but after Mature reflection of such results to be expected. Our tools so rough that register only the largest, most rapid giant planets might have on the Central star noticeable impact. It is therefore not surprising that today's telescopes registered only monstrously large planet, which are also rapidly move in space. If somewhere there existed an exact twin of our Solar system, our gross tools probably would not have been able to locate it.

Perhaps the situation will change after the launch of spacecraft "Koro", "Kepler" and TPF (which means "earth-Seekerx planets"). It is assumed that these observatories will be able to find in the space of a few hundreds of earth-like planets.

"Corot and Kepler, for example, must seek a faint shadow cast by the planet earth-like on the surface of the Central star, a little loosening its light. Although the planet itself to see fails, the satellite will be able to register a slight fall Shine Central star.

French satellite Corot" (its name is composed of the letters of French words "convection", "rotation" and "the passage of the planet") successfully launched in December 2006; this is a new starting point, the first space probe to search for planets outside the Solar system. Scientists hope to find with it, from ten to forty planets of the earth type. If their expectations are not justified, then we can talk about the discovery of stone planets - and not the gas giants - just several times exceeding the size of our Earth. In addition, the "Kingdom", probably, will add a new row to the already existing list yupiteropodobnyh planets. "Kingdom", in contrast to the current ground-based instruments can detect planets of any size and of any nature," says astronomer Claude Catala. The researchers hope that this satellite will scan up to 120,000 stars.

At any time you can expect reports that "Kingdom" found in space first planet earth-like, and this moment will be the turning point in the history of astronomy. Maybe in the future people will feel the shock when looking at the starry sky as they will know exactly what there at distant stars, planets suitable for intelligent life. Looking to heaven, we may become seriously question: and not looking anyone back at us?

The launch of the satellite "Kepler" NASA currently plans to may 2009 the Satellite is equipped with so sensitive equipment that can be expected to discover in outer space to several hundred earth-planets. He will have to measure the brightness of 100,000 stars and discover a while passing planets stellar disk. During the four year period covered by the agenda, "Kepler" has to observe and analyze thousands of stars at distances up to 2000 light years from the Sun. According to rough estimations of scientists, for the first year in orbit, the satellite should detect:

• 50-size planets around the Earth;

• 185 planets larger than Earth by about 30%;

• 640 planets of approximately 2.2 times larger than the Earth.

Perhaps the most faithful chance to discover earth-type has Observatory TPF, or Terrestrial Planet Finder. After several delays the launch is planned for 2014[23]; this satellite will, with great accuracy, to analyze a hundred stars at distances up to 45 light-years. It is supposed to equip its two separate devices for finding distant planets. The first of them is a coronagraph, a special telescope, which blocks the light of the Central star, weakening it a billion times. This telescope will be three to four times croup her and ten times more precisely space telescope named Hubble. The second device on TPF will be the interferometer can due to the interference of light waves to weaken the light of the Central star in a million times.

Meanwhile, the European space Agency plans in 2015 or later to launch its own space system for search of distant planets called "Darwin". It is supposed, that it will consist of three telescopes of about 3 m in diameter, which will fly "building" and work as one large interferometer. This Observatory will also do a search in the space of earth-like planets.

If scientists really will be able to find in the space of several hundred earth-planets, is, among other things, will allow a more efficient allocation of efforts for the SETI program. Instead of sifting through all nearby stars in a row, astronomers will be able to focus on a small number of stars near which may include terrestrial planets.
What they look like?

While astronomers are looking for aliens in space, other scientists on the basis of data of physics, biology and chemistry are trying to guess what it must be like alien life. Isaac Newton, for example, wondered why all the animals we see around us, have bilateral symmetry (they all have symmetrically located two eyes, two hands and two legs")? It is a happy chance or Providence of God?

Today biologists believe that during the Cambrian explosion, about half a billion years ago, nature experimented with a huge number of various forms and types only then appearing tiny multicellular creatures. Some of them had a chord in the form of the letters X, Y, or Z.

Others had a Central symmetry, like modern sea stars. Casually among the other appeared creature with a chord with the letter I, and bilateral symmetry of the body - and it became the ancestor of most mammals on Earth. Thus, in principle, the alien intelligent life does not have to be a humanoid and have bilateral symmetry - the one, which actively uses Hollywood with the image of aliens.

Some biologists believed that the reason for the diversity of all life forms during the Cambrian explosion is in "arms race" between predator and prey. The emergence of multicellular organisms, able to absorb and digest other organisms, gave impetus to the rapid evolution of the one and the other; each trying to outwit your opponent. Similarly, during the cold war arms race between the Soviet Union and the United States made those and others to move, so in any case to keep up.

Studying the origin of life on Earth, you can make some assumptions and how can occur intelligent life. Scientists believe that intelligent life will likely need:

1) what is the vision or other sensory mechanism, which allows to study the environment;

2) some mechanism for grasping is mahatsit opposed fingers, as we have, but can be and tentacles, claws or other devices;

3) some sort of communication system, such as speech.

These three conditions are necessary in order to feel the reality, and, with the time and manage it; both of these qualities are the distinctive features of the mind.

But any certainty ends. Contrary to what we see every day on television, aliens do not have to be like men. Wide-eyed, like children aliens from movies, television suspiciously reminiscent of aliens from second-rate films of the 50-s of the last century; yet then this image is firmly entrenched in our subconscious mind.

(Some anthropologists, however, add to the three conditions of occurrence of the fourth reason; this condition must explain the following interesting fact: people are much smarter than you need to survive in the forest. Our brain is able to master the principles of space flight, quantum theory, complex mathematics - obviously, these skills are nowhere forest hunters and gatherers. Why these redundant capabilities of the brain? In nature, if we examine a couple of animals, also with the skills, far exceeding the requirements of survival, such as leopard, and the antelope, is the fact that between the two was the "arms race". Similarly, some scientists believe that there is a fourth condition is biological arms race, pushing a view to the development of the mind. Perhaps, in our case the "arms race" was between different individuals of the same - our - kind.)

Think of the enormous variety of life on Earth. If someone in a few million years has been focused on the selection of octopodes, one can assume that they too would have been reasonable. (We separated from apes 6 million years ago, probably because it was poorly adapted to the climate change on the African continent. On the contrary, the octopus is very well adapted to life in the submarine shelters under the rocks and so many millions of years does not change.) Biochemist Clifford Pickover says that when he looks at any crustaceans mad, jellyfish with soft tentacles, grotesque worms-hermaphrodites and other mould", he understands that "God has a sense of humor and that we are yet to see in the Universe is a reflection of all of this in some form".

But Hollywood is probably correct when he depicts representatives of other intelligent life forms carnivorous. Aliens, predators, of course, guarantee the film higher fees - but not only; it has some truth. As a rule, predators smarter than their victims. To catch prey, they are forced to plan, track, hide and attack from ambush. The foxes, dogs, tigers and lions eyes are ahead, the better to estimate the distance when jumping. Two eyes allow them to see three-dimensional stereo and to focus on the victim. On the other hand, production - such as deer and rabbits, is enough to know where and how to escape. Their eyes are on different sides of the head, providing a full view, and allow to see all around 360 degrees.

In other words, it may well be that the extraterrestrial intelligent life also appeared as a result of the evolution of species with eyes or other sensitive body-on the head from the front. Perhaps for these creatures is characteristic also does meat-eating, aggression and territorial behavior that we observe in the Land of the wolves, lions, and people. (But since these life forms appeared, apparently, on the basis of completely different DNA molecules and proteins, they should be of no interest for us to eat or to mate with us.)

You can also use the knowledge of physics and suggest kakogabout the size can be a body like creatures. Assuming that they live on the planet earth-like and, like the terrestrial beings, have density fabrics, approximately equal to the density of water, we can exclude too large sizes due to the law of scale; this law States that the increase in the size of any object laws of nature for him literally change dramatically.
Monsters and the law of scale

Consider the example. If king Kong existed in fact, he never could terrorize new York. On the contrary, at the very first attempt to make a step he would break his legs. The thing is that, if you take the monkey and to increase its proportion to ten times its weight will increase in proportion to the volume, i.e. a thousand times (10 x 10 x 10 = 1000). So the monkey became a thousand times harder. But her strength was increased in proportion to the thickness of the bones and muscles. The cross-sectional area of the bones and muscles increases in proportion to the square of the linear values, i.e. ten times (10 x 10 = 100). In other words, if king Kong is 10 times more than ordinary monkey, he will be superior to its power, only a hundred times, and to weigh a thousand times more. Therefore, if you increase the size of the monkey weight grows much faster, than the power. Comparatively speaking, the king Kong will be 10 times less than usual monkey. That's why his feet immediately breaks.

I remember in elementary school our teacher was surprised at the strength of an ant can lift the sheet, many times heavier than the ant. The teacher made a conclusion that whether ant the size of a house, he could easily lift and carry this house. But this assumption is not true. The reason is the same as in the case of king Kong. If the ant was the size of a house, his feet, too, would break. If you increase the ant a thousand times, it will be a 1000 times weaker than usual ant and therefore will collapse under its own weight. (And suffocate. Ant is breathing through a hole in the side. The cross-sectional area of the air channels grows as the square of the radius, and the volume of ant - as the cube of the radius. Thus, the ant 1000 times more than usual will receive 1000 times less air than is necessary for normal supply of oxygen to the muscles and tissues of the body. Incidentally, this is why Champions in figure skating ice skating and gymnastics are, as a rule, people of small stature, but normal proportions. They have greater muscle strength per unit weight than tall people.)

With the help of the law of the scale, we can also determine the approximate parameters of animals on Earth and, probably, aliens in space. Heat radiated a living organism, in proportion to surface. Therefore, if you increase the animal's 10 times its heat loss will grow up to 100 times. But the amount of heat in the body is proportional to its volume and therefore will increase by 1000 times. Consequently, large animals lose heat more slowly than small ones. (This is why in the winter we first frozen fingers and ears - they have maximum relative surface area; that is why the little people freeze faster than larger ones. This can explain why Newspapers are burned very quickly - they have a very large relative size, and thick logs, burning slowly, they have the surface area is relatively small.) This explains also why the whales in the Arctic are teardrop-shaped - of all geometric shapes minimum surface area per unit mass possesses sphere. And why insects in a warm climate can afford arbitrary form with relative large surface area per unit mass.

In the film Studio of disney's "Honey, I shrunk the kids" all family members be decreased to the size of ants. Thunderstorm is coming, and we see in microcosm tiny drops fall in a puddle. Actually raindrop from the point of view of the ant should not look a tiny bit, and huge water hemisphere. In the ordinary world hemispherical volume of water will be unstable and will run under its own weight, but in microcosm force of surface tension is relatively big and easy to retain water in the hemispheric scale (imagine a drop in the worksheet).

Similarly, on the basis of the laws of physics we can estimate the ratio of surface area to volume for the animals living on distant planets. These laws tell us that aliens from outer space, most likely, will not be giants, which very likes to portray science fiction. Rather, they will be reminded by the size of the us. (Whales are far superior to us in size, because we live in a more dense environment, the sea water. That is why a beached whale dies, crushed by its own weight.)

The law scaling means that dive deeper and deeper into the microcosm of the laws of nature change. This explains the fact that quantum theory seems so strange because it is contrary to our understanding of the Universe, based on experience and common sense. The law scaling excludes familiar to us from the science fiction idea about nested worlds (the essence of it is that in every atom can hide an entire universe, and Vice versa, our galaxy is the atom of another, much larger universe). This idea, in particular, was used by the authors of the film "Men in black". In the final scene of the film, the camera away from the Earth into view the planets, stars, galaxies, and in the end it becomes clear that our entire universe is a ball in the game giant representatives of a different mind.

Actually Galaxy am not like the atom and the electrons in their shells are nothing like the planet. We know that all the planets are not similar to each other and can go around the Central star on any orbit. In the atoms of all subatomic particles exactly the same. They can't go around the nucleus at any distance; on the contrary, they can only move in discrete orbits. (Moreover, unlike planets electrons are able to behave unusually, contrary to common sense, for example, be in two places at once, or to possess the properties of waves.)
Physics of advanced civilizations

To talk about what can be a space civilization, too, can benefit from the knowledge of physical laws. If you look at the development of our own civilization over the past 100 000 years, i.e. from the moment in Africa, the first modern humans, you can see that this story is growing energy consumption. Russian astrophysicist Nikolai Kardashev suggested that stage of development of extraterrestrial civilizations of the Universe can also be classified by the level of energy consumption. He divided all possible civilization into three groups:

1. Civilization I type: those who collects the planetary energy, by using the incident on the planet sunlight. Perhaps representatives of these civilizations captured the energy of volcanoes, learned how to control the weather, monitor earthquakes and build cities in the depths of the ocean. All the energy of the planet is under their control.

2. Civilization II type: those who fully utilizes the energy of light, making them 10 billion times more powerful civilizations I type. Federation of planets in the TV series "Star trek" is civilizations II type. Such a civilization, in a sense, immortal; none of the known factors, such as ice age, an asteroid impact or even a supernova, unable to kill her. (If their own star soon going to explode, these creatures can move to another star system, or even to transfer to another star in your own planet.)

3. Civilization III types: those who can use the energy of the whole galaxy, which makes them a 10 billion raznovrstan civilizations II type. This type correspond civilization Borg in Star trek, the Empire in Star wars galactic civilization in the series Asimov about the Foundation. Each of these civilizations colonized billions of star systems and are able to use the energy of the black hole in the center of the galaxy. They are free to travel across the galaxy.

Kardashev believes that any civilization, the energy consumption of which is growing at a moderate speed [a few percent a year), will rapidly move from one level to another; such a transition will take it from a few thousand to several tens of thousands of years.

As I already told you in my previous books[24], our civilization can be considered a civilization type 0 (because our machines are working on the energy of combustion of dead plants, oil and coal). We use only a tiny part of the whole solar energy that goes to our planet. But already today we can see how on Earth are born the first signs of civilization I type. Internet - fetus system of telecommunication, which will cover in the future the entire planet. The emergence and development of the European Union, created to counterbalance the North American free trade area, you can see the beginnings of Economics I type. English has become the main language of international communication on the Earth, the language of science, business and Finance. I think he may be the language of civilization type I, which will be speaking literally all inhabitants of the planet. Local culture and traditions will continue to flourish on Earth in thousands of different options, but for the whole mosaic of Nations and nationalities will overlap single earthly culture is perhaps the dominant feature in it will serve youth culture and commercialism.

Successful transition civilization from one level to another is not guaranteed. For example, the most dangerous may be the transition from type 0 to type I. Civilization null type is still suffering from sectarianism, fundamentalism and racism, typical of the period of rapid development, and it is not clear, you should determine whether these tribal and religious passion to make a transition. (It is not excluded, that's what we see in the Galaxy qivilitati I type because of the transition, as a rule, does not, civilization destroys itself. Someday, after reaching other stars, we may come across the remains of civilizations who killed themselves: the atmosphere is their planet has become radioactive, say, or too hot and uninhabitable.)

When civilization reaches III stage, she has enough power and knowledge to be able to freely travel across the Galaxy and, say, to visit the planet Earth. Such civilizations are quite capable, like in the movie "2001" is to be spread across the Galaxy in search of intelligent life self-replicating automatic probes.

But civilization III type unlikely to want to visit or get us, as in the movie "independence Day", where such civilization spread through the galaxy as grasshoppers, capture planets one by one and sucking of these resources dry. Actually in space countless dead planets with the richest reserves of mineral resources, and they can freely assemble, without contacting stubborn local population. The attitude of civilization III type we can compare with our relationship to the ants and ant hill. We won't bow down over the nest and to offer its inhabitants a beads and other trinkets; rather, we simply will not pay attention to them.

For ants main danger is not that people suddenly want to invade anthill or destroy ant genus. The main danger is that the anthill hurt people, and just casually demolished. Do not forget that if we talk about energy consumption, the distance between civilization type III and civilization null type is much more than between us and the ants.
UFO

Some people claim that aliens have been on Earth and that they belong to a mysterious UFO. Having heard about flying saucers, scientists, as a rule, roll their eyes and reject any possibility of their representatives alien civilization; usually discouraged from that interstellar distances are too great. But despite the reaction of scientists, the number of reports of UFOs over the years, not reduced.

The first sightings of unidentified flying objects date back to the beginning of written history. For example, in the Bible the prophet Ezekiel mentions mysterious "wheels within wheels in the sky; some believe these words describing UFO. In 1450 BC in Egypt, during the reign of Thutmose III, the Egyptian priests left a description of certain events, attended by fire circles" brighter than the sun, size of about 5 m; this not appeared for a few days and eventually rose to the sky. 91 BC Roman author Julius Obseques wrote about the "round object like a ball, oval or round shield, which was moving across the sky". In 1235, the Japanese General Eresume and his army were seen in the sky near Kyoto strange glowing orbs. In 1561 in the sky above the Nuremberg in Germany saw a lot of objects that as if were engaged in a dogfight.

In the middle of the XX century, the U.S. air force has undertaken a large-scale study of various messages about seeing UFOs. In 1952, the air force launched the project "Blue book", which analyzed 12 618 such messages. In the final report said that the vast majority of them can be explained by the observation of natural phenomena or conventional aircraft, as well as intentional deception. However, 6% of cases received no explanation. In 1969 there was a report Condon, where he rejected any possibility of extraterrestrial origin of UFOs and the benefits of such research, and the project "Blue book" was closed. This was the last known project of its kind in the us air force.

In 2007, the French government has acquainted the public with developed over many years of data on UFOs. The report, published on the Internet the French National centre for space studies, covers 1,600 sightings of UFOs for over 50 years; it 100 000 pages of stories of witnesses, film and audio records. The French government claims that 9% of cases can be explained fully, 33% have a plausible explanation, but all other reliably explain failed.

Of course, an independent review of such communications to conduct very difficult. In General, most of the messages about seeing UFOs can put to rest as unreliable, if to consider the following.

1. The planet Venus is the brightest object in earth's sky after the moon. It is very far from the observer, so if you are driving a car, it seems that this shining point is behind you, and deliberately. The same impression, by the way, is created on the moon surface. People judge the distance to a moving object, comparing it with other objects around. The moon and Venus are very far and compare them to us nothing, they do not move relative of the objects surrounding us, hence the illusion that these celestial objects follow us.

2. Marsh gas. If on wetlands temperature inversion occurs, the emitted gas can accumulate over the ground; sometimes he even slightly off. Small clusters of gas, separating from large, can create the impression resignation leaving "ship-womb".

3. Meteora. These heavenly bodies can a few seconds to draw on the night sky bright streaks, giving the impression of controlled flight of the ship. Sometimes a meteor can be separated, again giving the impression resignation leaving "ship-womb".

4. Atmospheric anomalies. All kinds of lightning during thunderstorms and unusual atmospheric phenomena can light the sky in the most unexpected way, creating the illusion of a UFO.

In the XX and XXI centuries stories about UFOs can be thrown and other phenomena.

1. Radar echo. The radar radiation reflected from the mountains and other natural objects may create an echo, which will also take the antennas. This echoes can even move around the screen zigzag or, at enormous speed - it's just the echo.

2. Meteorological and other research balloons. The military in his controversial report argued that the reason famous hearing about the accident in 1947, an alien spaceship in Roswell, new Mexico became the failed balloon project Mogul - a top-secret project on monitoring radiation levels in the atmosphere in case of nuclear war.

3. The aircraft. There are cases when the cause of messages about UFOs became passenger and military aircraft. This is especially true in the case of the experimental flight of the latest experimental aircraft, such as the bomber "stealth". (The U.S. military even encouraged rumors about flying saucers, in order to divert attention from its own top-secret projects.)

4. Deliberate deception. Some of the most famous images of flying saucers are actually fakes. One of the most famous flying saucers with Windows and supports, in fact represented a slightly altered a feeder for the chickens.

Based on the above it can be rejected at least 95% of cases of UFO sightings. But the remaining few percent still remain unexplained. The most reliable sightings of SU include: a) the numerous testimonies independent, trustworthy people and b) evidence from various sources, say data of people observers and radar. Such cases are more difficult to dismiss, as several independent sources partly confirm each other. So, in 1986 UFO over Alaska watched the passengers of flight 1628 Japan airlines JAL; the Federal aviation administration of the USA has conducted an investigation of the incident. In addition to passenger aircraft UFO observed and ground-based radar. Similarly, in 1989-1990 radars observed over Belgium black triangles; they saw also the NATO radar and aircraft-interceptors In 1976 with the UFO spotted over the Iranian city of Tehran; the result, as is evident from the documents of the CIA, has led to numerous hardware failures on the interceptor F-4.

Scientists is frustrating is the fact that out of thousands of registered cases of UFO sightings none gave any real material evidence which could be studied in the laboratory and to get repeatable results. Any foreign DNA, no strangers computer chips - no material evidence landing alien ships to Land.

Suppose for a moment that UFO still are not illusions, and real space ships; then we can ask ourselves what it ships. Bot some of the characteristics that indicate the witnesses.

A. it is Known that they can dramatically change the direction of flight.

B. it is Known that near them ceases to operate the ignition in the car and at all electrical appliances.

B. They can silently hanging in the air.

None of these characteristics is not related to terrestrial missiles. For example, all known to us missiles operate on the basis of Newton's third law (the operating is equal to counteraction); but observed UFOs don't seem to emit a jet-and nothing. In addition, overload in a flying saucer, videlyaushey in the sky rapid zigzags, would have to be 100 g or more; such overload is not able to withstand any living creature on Earth,

Does modern science to explain such characteristics flying saucers, still assuming that the reports are true and UFOs exist? In the movie, for example in the film "Earth vs. the flying saucers", it is always assumed that these ships are run by aliens. But much more likely that these ships, if they exist, - automatic (or their flying halfway organic, half mechanical susociety). This would explain the maneuvers, which would have squashed any living creature.

The ship is able to block the ignition and silently hanging in the air, suggesting as propulsion magnetic forces. The problem is that the magnet always two poles, North and South. If you put such a magnet in the Earth's magnetic field, he'll just turn around (like a compass needle), but will not hang in the air like a UFO. In General, if the South pole of the magnet moves in one direction, then North moves in the opposite, - magnet unfolds, and in General it is not moving.

One possible solution to this problem is the use of "monocle", i.e. magnets with only one pole, North or South. In normal conditions, if you break open the magnet in half, you will not get two monopoles. Instead, each spouse will become independent magnet, with its own two poles, i.e. will become another dipole. No matter how much you crushed magnet, you will always find each chip two poles. (This process can be continued down to the atomic level; each atom is a dipole.)

Scientists have never been able to see the monopole in the laboratory. Physics tried to find and photograph the trail monopole on their equipment, but it also failed (except in one very controversial images in Standardsconvergence in 1982).

Although monopoles reliably could not see, physics mostly sure that once - namely at the moment of the Big Bang the universe was a dime a dozen. This idea became the latest cosmological theory of the Big Bang. But after the Big Bang, the universe has expanded sharply, and the density of monopoles in it respectively decreased, why is it so difficult today to see them in the laboratory. (Actually, the absence of monopoles around-this is the key fact which has led physicists to put forward the idea of inflationary stage in the development of the universe. So today in physics firmly rooted concept of relic monopoles.)

Thus, it is possible to imagine the space race, is able to collect these "primary monopoles", remaining after the Big Bang, using a large magnetic "network", scattered in space. Gaining enough monopoles, this race will be able to fly freely in space, using only existing in the universe magnetic fields. Given that Monopoli currently very interested in many cosmologists, the existence of such ships, of course, does not contradict with modern physical notions.

Finally, you can be sure that any civilization that is able to circulate in the universe spaceship, the long-mastered nanotechnology. This means that ships such a race may not be very large; but they can send millions to search for and study of the inhabited planets. The best bases for nanocarblab would, of course, a deserted moon. If so, and on our moon once visited, possibly, representatives of civilization III type, like explained in the script of the film "2001", the most realistic, perhaps the image of a meeting with an extraterrestrial civilization. More than likely, the ship that civilization would be automatic and descended to the moon. (Perhaps it will be a hundred years before we will be able to scan the whole moon in search of anomalies radiation and discover ancient evidence visits of nanocarblab in our Solar system.)

If our moon in the past actually visited the representatives of a civilization, or, say, it is the basis of nanocarblab, we can understand why UFOs are not necessarily large. Some scientists reject the very possibility of the existence of the UFO just because they don't meet any of the giant jet engines, which are now really consider our engineers, is certainly not a once-through nuclear engines, not giant sails, movable laser with the wind, not pulsed nuclear ships, each of which can reach several kilometers in diameter. UFOs may be the size of a jet plane. But if on the moon there is a constant base of the last visit, they don't have to be large; they can easily fill up the database. Then on Earth see, most likely, automatic recon ships, which started with the lunar base.

Given the rapid progress of the program SETI and the discovery of new extrasolar planets, contact with extraterrestrial life - except, of course, that it exists in our immediate vicinity, can occur in this century, which causes include such contact to the class I impossibility. If in space there are indeed other civilization, the next obvious question is: will we ever get to them? And what about our own distant future, when the Sun begins to expand and will be ready to absorb the Earth? Is our fate is really out there among the stars?