The history of other worlds then is roughly the same as that of our own world: a competition between life forms, some able to win through, some unable to do so through bad placement of organs. The extinct billions of experiments that failed are not around for us to examine. Life, structuring itself for more efficient survival, remains.
To further illustrate his point, Ehricke cites airplane design in-the early 1900s: “Fantastic varieties emerged from many countries, all experimental, all different. But today by natural selection, there is only one optimum type of aircraft for certain speeds. So if conditions on other worlds are similar to ours, their creatures could show some physical resemblance to us.”
This allowed, we have no way of guessing what variations in mankind itself could make a more efficient creature with greater survival characteristics. A third eye in the back of our heads, for instance, would be a lifesaver in this age of the galloping pedestrian. On a world where the air is thick, the beings would need extremely small mouths and nostrils to cut down on intake. If the air is thin, they would need mouths and nose vents like barn doors.
To the lonely space man, an alien woman with the above features would hardly be attractive. Right here, the entire field of esthetics looms before us. Astronautical history may depend on those concepts of beauty and utility our men take along as unacknowledged cargo to the stars. Countless books will have to be written under the general title: Esthetics and Etiquette for Other Worlds. Otherwise we are in danger of mistaking a rough skin for a rough mind, a third eye for an evil eye, a cold hand for a cold and hostile heart.
We have our own history of Indian-white relations to look back on with dismay. But these were, though savages, men. Confronted with beings resembling cockroaches, will we pause to consider whether their I.Q. is 50 or 250? Or will we simply build the grandest shoe in history and step on them?
Our first astronauts then must be the wisest and most temperate men, slow to revulsion, quick to sympathy, capable even of having their concepts of male-female sexuality shaken. On the planets of Tau Ceti sexes may be combined in one body or, worse from our lusty view, may be lacking altogether because more efficient if less invigorating ways have been found by nature to keep a race going.
Thus far we have dealt with planets enjoying climates as bright and fine as ours. But even on such worlds, spendthrift creation is almost certain never to repeat an accident in the same way. Man, ape on the way to being angel, is but one of a trillion happenstances, neither better nor worse than trillions of others thrown up for grabs in island universes we will never see.
So while we may find cities on other worlds, they will not look like cities, the houses not quite houses, and the furniture and art all a little wrong to our jaundiced eyes. We will watch games that seem hardly games, hear songs just barely songs, all on worlds exactly like ours in natural environment.
But what of planets swinging about redder or whiter suns than ours, covered with lethal atmospheres where we will move like deep-sea divers in our space suits?
Earth life is based on carbon and oxygen. Does it have to be, on other worlds? No. Here are some other possibilities:
A world where the air is a hydrogen-peroxide vapor. This vapor, breathed in by animals, could be broken down into oxygen and water for use by their bodies.
A world where fluorine might be inhaled as a gas by living creatures. The skin of flourine-breathers, however, would be leathery and unpleasant and the world itself so nightmarish that our space men probably would not stay more than an hour.
But in the creation of life the atmosphere of planets is less important than the kind of warm-broth seas that covered them in their formative years. We men are built largely of carbon which, billions of years ago, formed the basis of increasingly complicated chemical compounds that changed and changed again until at last they came alive.
We carbon creatures are prejudiced in our own favor because, in all truth, carbon life can survive environmental dangers that other noncarbon forms could not possibly stand. So versatile is it, in fact, that if ever carbon life and silicon life came into existence simultaneously, carbon life would wipe out the silicon life. So versatile is carbon that out scientists long ago divided their studies into organic (carbon) chemistry and inorganic chemistry. Carbon, a virtuoso performer, can do more tricks than the whole theater of all the other known chemical elements. Silicon is the only other element that approaches it. Can we then expect to find silicon life in the universe?
There is one serious flaw in imagining silicon creatures. We breathe out carbon dioxide, which is a gas. “Silicon creatures,” says Dr. Tombaugh, “would breath out silicon dioxide, which is quartz.”
It is hard to imagine an animal exhaling crystals of quartz as it moves through its world. Silicon life would need to breathe something like flourine. This would cause it to exhale silicon-tetra-fluoride, after using the liberated energy. This, too, would result in a creature far removed, if even faintly resembling, ourselves.
What we have guessed so far is unpromising, unsettling, sometimes terrifying. How nice it would be to step off our rocket on some far world and find just home folks like us.
It could happen.
Thomas Gold of Cornell’s space research group believes Earth may have been visited by cosmic neighbors a billion years ago. Finding the climate not to their taste, they dumped their picnic trash and left. From this discarded lot, bacterial life in its own good billion-year time evolved up to present-day man. We, too, some year, may seed other worlds with Coke bottles, paper napkins and orange peels from which our germs, invisibly stamped with our images, might rise up and walk on legs a billion years hence. So the creatures of the universe, through an intergalactic untidiness, might summon forth twins a thousand million sunrises apart.
Improbable. But improbable, too, is the thought that spores, drifting down the star winds, may have carried life from other nebulae to ours. Or the thought that perhaps huge meteoroids, shot across the abyss, carried out the work. Yet there is evidence that this may have happened. Dr. Melvin Calvin of the University of California at Berkeley has discovered recently, in examining meteor bodies, molecules resembling the basic stuff of genetic material here on Earth. In these blazing gifts from space he found prebiological forms that have not been on Earth for millions of years. These chemical combinations were the very ones that had to occur before life could stir.
In the scientific laboratories experts are experimenting with the creation of life in a test tube. In an artificial recreation of our raw and nightmarish environment when lightnings prowled our world like unchained beasts, Scientist Stanley L. Miller subjected a mixture of methane, or marsh gas, hydrogen, ammonia and water to electrical discharge. The result was the production of amino acids: Biochemist Sidney W. Fox, of Florida State University, has carried the process one significant step further: from the amino acids he has produced substances resembling proteins which then form tiny spheres which look like—and in some ways act like—bacteria.
Life in a test tube: a mystery.
Life on Earth: a mystery.
Life on other worlds: a mystery.
The mysteries move closer together through the immense shuttling of our thoughts, our laboratory devices, our far-traveling rockets.
The dust which once flew in the voids, the stuff of the sun, the mineral trash of Earth, has reared itself up in our time to become man—to speak in tongues, to put forth hands and, with one of its billion-year-developed senses, to see those beckoning stars. That dust which came down through cycles of destruction and rebirth now desires to seek other dusts, to know what further shapes strange suns and gravities may have given them.