A STARSHIP FROM EARTH is traveling in the galaxy, its mission to establish communication with extraterrestrial intelligences and civilizations.*
For years SETI (Search for Extraterrestrial Intelligence) has explored the 200 billion stars of the galaxy, huge dish antennae searching for something, anything other than the random noise of the Cosmos. At last, the computer of the spectrum analyzer which reads the tapes of all the received transmissions picked up a pattern, that is, a repeated signal, which, however, could not be interpreted. Was it a signal from an intelligence or was it like the Coke bottle in the movie On the Beach, which was leaning on a telegraph key in deserted California and which a fitful breeze blowing a curtain caused to send out a random letter or two?
The starship has a transmission-receiver capability for the entire electromagnetic spectrum, but especially in the range of radio signals, since it is known of course that the Cosmos is filled with emissions in this part of the spectrum, from pulsars, quasars, radiation belts, and so on.
The objective of the starship is to exchange information with other civilizations comparable with or superior to our own. It has been calculated that the probability that such civilizations exist is overwhelming. What the designers of the project hoped to learn was the level of technology of other civilizations, the degree of evolution, biology, type of metabolism, etc.
The time is the year 205 °C.E. (Common Era, so called because, though the era is post-Christian, it proved useful to retain the year of Christ’s birth). The acceleration of vehicles to speeds approaching the speed of light is possible, the aging process is accordingly reduced, and the problems of communication delays are minimized.
The assumption was made that as organisms evolve in the Cosmos, a level of intelligence will be reached so that it will be possible to transmit information. Mathematics and science might be used as the basis of a common language. Mathematics is the same everywhere. The prime numbers 1, 2, 3, 5, 7, 11, 13 … are prime everywhere. The physics of the Cosmos is the same. For example, since hydrogen is the most abundant atom in the Cosmos, one might use the proton and electron spin of the neutral hydrogen atom as the binary number 1. Using such a binary system, the project designers hoped that it might be possible to establish a vocabulary and transmit information about the earth and its star, for example, its position in relation to the fourteen major pulsars of the galaxy, and to put similar questions to other intelligences.
Organisms transmitting signals were, in fact, encountered. The trouble was that the responses received were not acknowledgments or statements of information but were rather countersignals of one sort or another, responses which seemed to express something like excitement or alarm or anger, often actual movements of the organisms themselves. Thus, rather than information being obtained, various behaviors were encountered — hostile, aversive, coming close or going away, flight or fight, and in one case what appeared to be an attempt at sexual union.
In fact, two such creatures were encountered in the solar system.
(1) In the outer atmosphere of Jupiter, large gaseous clouds were sighted. It was determined that they were self-contained organisms of some intelligence because they were self-propelled, moving about by emitting jets of hydrogen. They injested organic molecules and excreted helium and methane, and were observed to reproduce by fission. But despite every effort to communicate, e.g., by transmitting prime numbers in various frequencies of the electromagnetic spectrum, the only response of the clouds was to speed away or come close and surround the ship like a sportive school of whales — or to rise and sink like so many hot-air balloons.
(2) Skirting Saturn’s moon Titan with its heavy atmosphere of methane, another sort of creature was encountered, small glittering anemone-like organisms with spicules of methane crystals and a beak-and-sucker mouth for devouring the brown sludge of organic molecules formed on Titan’s surface by the ultraviolet light of the sun. Upon the transmission of radio waves of the frequency 1420 megahertz, the creatures were thrown into violent excitement, for all the world like the behavior of male gypsy moths upon the reception of the female pheromone. They flocked to the ship and attached themselves to its tiles and windows, using their sucker-like mouths. It was not clear whether such a response was a manifestation of hunger or hostility or an attempt at sexual union.
At last, five years later, near Proxima Centauri, communication was established with an extraterrestrial intelligence. Orbiting the third planet of Proxima Centauri (PC3), of PC’s twelve planets the one most resembling Earth, the earthship transmitted the prime numbers in the radio range of the electromagnetic spectrum. Almost immediately, the signal was returned — and imitated. But when the excited earthlings tried to descend, a glitch occurred in the controls, not once, but repeatedly — until it finally dawned on the crew that they were being held in orbit. Evidently, the earthship was being detained at a kind of checkpoint until its credentials were approved.
It was necessary to hit upon a mathematical and semantic vocabulary. The former was easy, again using the physical properties of the hydrogen atom, assigning the binary number 1 to the transition between the parallel and antiparallel proton and electron spins of the neutral hydrogen atom. Such a transition emits a radio-frequency photon of wavelength 21 centimeters and a frequency of 1420 megahertz — the reason for selecting this channel of transmission. An indexical lexicon was agreed upon. Thus, certain binary numbers were assigned to the suns of Centauri by transmitting the number along with the angle or declination of the suns from the path of transmission. Similarly, other names were assigned to other features, the other referents being “pointed at” and “named,” e.g., light, dark, other planets, pulsars, big, little, red, blue, near, far, down, up, here, there, I (the earthship), you (PC3), and so on. Plurals and abstractions and tenses were agreed upon. Goodness was a property attributed to cosmic particles which were beneficial to the metabolism of the PC3 organisms, evil to the ultraviolet rays, which were harmful. Even metaphor was arrived at: I am M4 today, meaning I am your fourth moon, PC3's fourth moon being bright, small, racy, refractile as a diamond. Or I am M6—sluggish, blue, misshapen, bored. Consciousness was defined as that property of a creature by which he draws attention to something, talks about it, or thinks about it. It was designated by a binary number which we shall call C.
A lexicon and syntax agreed upon, it was now possible for the earthship to transmit basic information about its origin, its sun, the geology, atmosphere, age of the planet earth, the biology of its organisms (e.g., C, H, O, S, H2O, PO4; deoxyribonucleic acid; mobile heterotrophs; surface dwellers; O2 breathers; sexual mammals, etc.), its technology (nuclear energic), its culture (two hundred nation-states, five global powers, sporadic brushfire warfare, environmental pollution), its science, its art (literary, iconic, musical) — a message ending with a sign-off and an invitation: Over and out — come back.
There followed a long pause, then an explicit warning: Maintain orbit until certain questions are answered—then the transmission of a binary symbol which the earthlings translated as something like the Hebrew shalom—then the transmission of comparable summary of PC3 information, indicating an organism with a bromine metabolism, an older civilization than that of Earth, and a superior technology (exponentiating, approaching asymptotic limit). Culture: global, gregarious, 40,000 genera, one symbolic language (!) (cf. Earth’s thousands), reproduction: sexual (!), biology: non-senescent (!): did that mean they did not age or die?!???; art: mathematical-poetic.