Ever since man had first looked up at the night sky, the glorious canopy of light and blue, he had wondered about the existence of intelligent life forms in other parts of this vast universe. However his inherent pride, his belief in his own divine origins and his faith in his special talents and attributes when compared to other species had not exactly encouraged a trend of thought that envisaged the possibility of existence of an advanced society or civilisation, elsewhere in the cosmos.
Man’s viewpoint of an anthropocentric world was hopelessly inconsistent with the disturbing concept of extra terrestrial intelligence. And rather strangely some modern scientists seem to be also of the same view, though they have reached such a verdict on the basis of an entirely different set of arguments. They speculate that only a civilisation or society which has a technology comparable to that of ours, and which has the urge to explore, colonise and communicate with other similar species, could be detected by our present limited technology. According to these scientists, since space travel would not be too expensive for such a society, any ship sent by them ought to have reached the earth by now. Since no such ship has arrived these scientists conclude by a negative argument that no such society exists.
A second argument used by scientists to refute the existence of extra terrestrial intelligence is rooted in their firm belief that life arose by sheer chance, and that a series of extremely improbable and complicated events must take place for life (as we know on earth) to evolve anywhere else also. Ironically this very same argument is also used by advocates of extra terrestrial intelligence to prove their diametrically opposite view-point.
Prior to the 16th Century it had generally been held that the earth had a pre-eminent position in the solar system and that man himself had a unique position on this planet. This attitude of “human chauvinism”, had been encouraged and also perpetuated by not only people who had no scientific back ground, but also by religious leaders and even intellectuals who had all been only too happy to believe in a notion that had given the human race a certain primacy in the physical universe. However, several new advances in science had shattered these myths. First of all Copernicus had proved that the Sun and not the Earth was the centre of the solar system-a fact that demolished the age old belief in the supremacy of man’s planet. Secondly astronomers had discovered that the solar system itself was part of a galaxy and, that several millions of such galaxies existed over vast stretches of space, separated by distances running into trillions of lightyears (A light year is the distance travelled by light in one year at a velocity of 186000 miles per second). The status of the earth had been reduced to the level of an ordinary satellite revolving around the Sun, which itself was a star of medium size.
Thirdly the findings of Darwin and others had established that man himself had descended from the lower animals by a long process of evolution involving gradual changes, as well as random mutations, proving that there was nothing exclusive about the way man had been created and that he was only an ordinary link in a long biological chain.
The realisation had also dawned that man had been precariously placed on this tiny planet in one remote corner of the universe, that even a minor fluctuation in the temperature of the star from which the earth derives light and warmth, could extinguish the spark of life; and that similarly even a small change in the speed with which the earth revolves around the sun or a slight alteration in its orbit could perhaps have disastrous consequences. Scientific materialism had demonstrated that in the vast immensities of astronomical space and geological time, life in general and human life in particular seemed to be having the ephemeral existence of the flame of a candle.
How then is there a justification for the search for extra terrestrial intelligence considering that a series of extremely complicated chemical and biological changes should have occurred in a particular sequence if life were to evolve. The answer lies in the hope expressed in certain circles that if the same conditions that had existed in the primitive atmosphere of the earth had existed elsewhere in the universe also, there is a good chance that life could have evolved there as well.
In order to assess the credibility of such an assumption, two scientists Harold Urey and Stanley Miller had conducted an ingenious experiment in the fifties in the University of Chicago. They had boiled in a sealed flask gases such as Methane, Hydrogen, Ammonia and water vapour which were believed to have existed in the earth’s early atmosphere. They had subjected the contents of the flask to an electrical discharge from a coil, thus reproducing in the laboratory the entire drama that had taken place in the early history of this planet.
The experiment had resulted in the formation of a kind of organic molecular soup, including four of the amino-acids essential to life. Scientists now have no doubt that molecules such as these had existed in th primeval atmosphere of the earth and that their mutual interaction had gradually led to the formation of the DNA (Deoxyribonucleic acid) which had the twin properties of (a) acting as a blue print for the creation of amino acids and (b) having the capacity to replicate itself. Once the DNA molecule, with its now famous double helix structure had made its appearance, the remaining stages in evolution had followed in succession on the basis of certain laws such as natural selection. Scinetists therefore are not unjustified in concluding that given the same set of conditions involving a similar atmosphere and random chemical changes, life could have appeared in the same fashion in other places also; particularly since organic molecules and compounds seem to be present even in the depths of inter stellar space, not to mention planets such as Jupiter and Saturn which incidentally do not appear to be supporting life forms due to other reasons such as temperature or the harshness of ultra violet light.
However man’s desire to search for extra terrestrial intelligence has remained unfulfilled mainly because of a lack of the scientific or technological capability to carry out such projects. But astronomers like the late Carl Sagan were optimistic, that man has now at his command the vast resources of radio astronomy, with the help of which he would be able to undertake a systematic search for extra terrestrial intelligence.
Any project that is involved in the task of search for life elsewhere in the universe has to essentially depend upon one major principle – the possibility that if an alien civilisation of sufficient technological capability exists, it might be broadcasting communication on some channel or frequency and that with a properly built receiving system we would we able to capture such a signal.
However, in the absence of prior knowledge about the precise location of the transmission or the exact frequency or channel on which the transmitter is broadcasting messages, the task of aiming the Radio Telescope and tuning in on the frequency in question, would be extremely complicated. Scientists assume that there are a few “hallowed” or special frequencies such as that of hydrogen (the most abundant element in the Universe) which should be acceptable and appealing to any advanced civilisation since the laws of physics are constant throughout the universe. (as stated above the element which occurs most frequently throughout the uni-verse is hydrogen which emits radiation at a certain frequency.)
Allowing for a certain margin due to the fact that the planet or star from which the alien civilisation is broadcasting is in motion with respect to the earth, and also making allowance for several other similar factors, one could assume that the frequency of the hydrogen element would undergo a change by the time it is received on the earth. Hence, scientists would like to study a whole channel of frequencies in the vicinity of the special frequency.
For example, a receiving station built by scientists in a prestigious university in America permits them to study a set of 128000 frequencies including the hydrogen frequency at the same time. A slightly broader approach is that of another group of researchers whose programme is expected to be able to study about eight million channels, though, it would also pay special attention to nearby stars. But while the former programme depends on it ability to finesse by concentrating on the special frequency region, the latter system hopes to achieve success by studying the entire radio spectrum in a systematic manner.
A large number of scientists from all over the world including Nobel Laureates, Francis Crick and Linus Pauling and Britain’s world renowned astronomer, Stephen Hawking have indicated their moral support for such projects. They feel that for the first time, man is in a position to communicate with other life forms in the universe if they exist, and that if this opportunity is lost, the skies of the future may be so jammed with frequencies from military and civilian transmissions that there would be no way of distinguishing an alien transmission from a transmissions emanating from the earth. Secondly a search if made in the above fashion would be much more thorough and accurate than any attempt made so far.
There is also a growing awareness among intellectuals in general that the cost of such a search would be nominal compared to the billions of dollars sunk into other avoidable and undesirable technology. There is a feeling that even if the experiment fails to find life elsewhere it would enable astronomers to give up the idea of this trend of research altogether and thus concentrate on other means of communication. It would also conclusively prove that there are not many civilisations in the vicinity of our galaxy which are transmitting signals at a frequency that is likely to catch attention of a technically advanced civilisation like ours.
Among those scientists who disbelieve the existence of extra terrestrial intelligence, are some who feel that the only way to settle the issue is by sending computerised, self-reproducing machines for a physical probe of heavenly bodies. In their view radio signals can be detected by only a technically advanced society, and so a comparatively less sophisticated civilisation may not be able to detect our signals. On the other hand a probe would be able to physically explore the local topography and send back vital information irrespective of the fact whether a planet is inhabited or not.
Such a probe can be programmed to create a whole new space colony of artificial life form in a far off stellar system. Scientists thus envisage the possibility of such artificial beings brought up entirely by Robots. But it would perhaps take at least another one hundred years to achieve the level of technology required to launch computerised probes successfully. Hence many scientists would rather choose the option of setting up receiving stations now itself on the ground as the project would be cheap, sensible and also change man’s view of the universe and of himself.
Scientists also speculate that apart from the mere cultural impact of discovering that mankind is not alone in the universe there would be other scientific dividends of far reaching consequences, such as the subsidiary benefits for radio astronomy. In any case many astronomers like Professor Frank Drake of Cornell University, U.S.A. are obsessively pre- occupied about the idea of searching for life in outer space. Drake has even gone to the extent of sending coded scientific radio signals which he hopes could be easily deciphered by any intelligent society in far off space. One such message sent by him has already crossed about seventeen light years. Drake has even written out an equation consisting of the factors that are likely to influence the possibility of existence of extra terrestrial intelligence.
One of the most fashionable concepts in respect of origin of life on earth, is a revolutionary theory suggested by Francis Crick the famous British biologist who along with James Watson, won the Nobel prize in 1962, for the discovery of the Double helix. He has suggested that an advanced civilisation that had developed billions of years ago somewhere in space had sent an unmanned rocket carrying micro-organisms to the earth, and these organisms that had been dropped in the primitive oceans of the earth had begun to multiply. Even though Crick himself is inclined to regard his new theory as being premature at this stage, though valid scientifically, most scientists would think twice before rejecting it outright, considering Crick’s scientific reputation and the fact that even intellectual giants like Peter Medawar regard, his discovery of the structure and biological functions of the nucleic acids as the greatest achievement of science in the 20th century. In any case Crick’s theory at least provides yet another justification to continue the search for extra terrestrial intelligence—particularly in an age that has grown accustomed to exciting tales of close encounters with aliens in one’s own backyard!