In his book Worlds in Collision, published in 1950, and still much discussed in scientific circles, Dr Emanuel Velikovsky declared that a giant comet had crashed into Mars and that Venus had been formed as a result of this collision. His theory can be proved if Venus has a high surface temperature, clouds containing carburetted hydrogen and an anomalous rotation. Evaluation of the data provided by Mariner II confirms Velikovsky's theory. Venus is the only planet which rotates 'backwards', i.e. the only planet that does not follow the rules of our solar system as do Mercury, the Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

But if a cosmically caused catastrophe is a possible reason for the destruction of a civilisation on the planet Mars, that would also provide material for my theory that the earth may have received visits from space in the very remote past. The thesis that a group of Martian giants perhaps escaped to earth to found the new culture of homo sapiens by breeding with the semi-intelligent beings living there then becomes a speculative possibility. Since the gravity of Mars is not as strong as that of the earth, it can be assumed that the build of Martian men was heavier and bigger than that of the earth men. If there were anything in this argument, we should have the giants who come from the stars, who could move enormous blocks of stone, who instructed men in arts still unknown on earth and who finally died out.

Never did we know so little about so much as today. I am certain that the theme 'Man and Unknown Intelligences' will remain on the agenda of research until every puzzle that can be solved has found an answer.

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Chapter Eleven - The Search For Direct Communication

At 4 a.m. on 1 April, 1960, an experiment began in a lonely valley in West Virginia. The big 85-ft radio-telescope at Green Bank was trained on the star Tau-Ceti, 11.8 light years away. The young American astronomer, Dr Frank Drake, who enjoys considerable fame as a scientist and acted as leader of this project, wanted to tune in to the radio transmissions of other civilisations in order to pick up signals from unknown intelligences in outer space. The first series of experiments lasted 150 hours. They passed into history as project OZMA, although it was a failure. The experiment was broken off, not because some of the participating scientists expressed the view that there were no radio transmission in space, but rather because it was realised that at the time there was no apparatus sensitive enough to reach the desired goal. OZMA will not be the only experiment of its kind. Possibly a radio-telescope will be erected on the moon that will be able to scan the immeasurable spaces between the stars for radio signals, free from terrestrial interference.

However, it must be asked whether the search for radio signals really helps our space research and whether it might not be more practical for us to do the sending of radio signals into space. Of course, we cannot expect unknown intelligences to understand Russian or Spanish or English and to be sitting there waiting to be contacted.

There remain three possibilities by which we can make ourselves known: mathematical symbols, Laser beams and pictures. The first of these seems most likely to succeed. In order to send such symbols we shall have to discover and fix Intergalactic wavelengths that stand a good chance of being received throughout the cosmos. 1420 megahertz would provide such a frequency, for that is the radiation frequency of the neutral hydrogen that results from the collision of hydrogen atoms. Since hydrogen is an element, this radiation frequency could be known throughout the universe. Besides, 1420 megahertz lies outside the over-crowded scale of terrestrial wavelengths. The possibility of errors and interference factors would be reduced to a minimum. In this way radio impulses could be sent into space and if unknown intelligences exist they would recognise them.

In this connection a news item from Die Zeit for 22.12.67 is most interesting. Under the headline 'The moon will be bombarded by flashes' we read:

'The distance of the moon from the earth is known to the nearest few hundred yards, but astronomers refuse to be satisfied with that. So astronauts on one of the first flights to the earth's satellite will take mirrors with them and set them up there. These mirrors—like the corner of a room— will consist of three reflecting planes standing at right angles to each other and will have the property of returning any light that strikes them back to the source of the light.

'This mirror system will be bombarded from the earth by a Laser emitting flashes of light each lasting for a hundred millionth of a second. The Laser will be used in conjunction with a telescope with an aperture of 1-50 metres. The light reflected from the moon will be picked up by this telescope and led to a photo-copier.

'The distance of the moon can then be determined to one and a half metres from the known speed of light and the time taken by a Laser beam for the journey there and back.'

The same kind of thing is also conceivable in reverse. Radio waves have been traversing the universe for a very long time. If my hypothesis is correct, isn't it credible that unknown intelligences are also announcing themselves to us? For example, the radiation energy of CTA 102 suddenly increased in the autumn of 1964; Russian astronomers informed the world that they had possibly received signals from an extra-terrestrial super-civilisation. This radio star CTA 102 was listed under catalogue number 102 by radio astronomers of the California Institute of Technology—hence its name.

The astronomer Sholomitski said in the lecture-room of the Sternberg Institute in Moscow on 13 April, 1965: 'At the end of September and the beginning of October 1964 the radiation energy from CTA 102 was much stronger, but only for a short time, then it diminished again. We registered this and waited. Towards the end of the year the intensity of the source suddenly increased again; it reached a second peak exactly 100 days after the first record was taken.' His chief, Professor Shlovsky, added that such fluctuations in radiation were very unusual.

Meanwhile the Dutch astrophysicist Maarten Schmidt has found out by exact measurements that CTA 102 must be about 10 milliard light years from the earth. That means that if the radio beams originated from intelligent beings, they must have been radiated 10 milliard years ago. But according to the calculations of present-day research, our planet simply did not exist at that time. This realisation could mean a kind of coup de grace to the search for other living beings in the universe.

But if the search for life in the universe had no chance of success, astrophysicists in America and Russia, at Jodrell Bank and at Stockert near Bonn in Germany would not be concentrating their research on what are known as radio stars and quasars with enormous directional antennae. The fixed stars Epsilon-Eridiani and Tau-Ceti are respectively 10.2 and 11.8 light years away from us. So radio waves aimed at these 'neighbours' would be about 11 light years under way and an answer from them could reasonably reach us in 22 years. Radio communications with more distant stars would take correspondingly longer; civilisations situated at distances reckoned in millions of light years are quite unsuitable for making contact with by means of radio waves. But are radio waves our only technical means of making such attempts?

For example, we could also make ourselves optically noticeable. A powerful Laser beam directed at Mars or Jupiter could not remain unnoticed, provided that intelligent living beings are in existence there. ('Laser' is the abbreviation for 'Light amplification by the stimulated emission of radiation'.) Another, somewhat fantastic-sounding possibility would be to cultivate vast areas of soil so that tremendous colour contrasts appeared which at the same time represented a geometrical or mathematical symbol of universal validity. One audacious but perfectly realisable idea: a gigantic equilateral triangle would have its 600-mile-long sides sown with potatoes; in this enormous triangle a circle would be sown with wheat. In this way a vast yellow circle, surrounded by a green equilateral triangle, would appear every summer. Incidentally, a most useful and productive experiment! But if there are unknown intelligences that seek us as we seek them, the colouring of circle and triangle would be a hint to them that these shapes were no freaks of nature. As I have said, that is one possibility. Someone or other has also advocated erecting a chain of lighthouses which radiate their lights vertically. The resultant sea of light should be arranged to have the shape of a model of an atom. There are all kinds of suggestions.