Varieties of vegetable life and the higher levels of animal life would be missing, says Tombaugh, because there is so little water. He adds: “Certain favored places on Mars, in the summer months, would have temperatures as high as 70°F., but the temperature drops to 30 or 40 below zero every night of the year at the Martian equator. In the antarctic night, the temperature must go some 200 below zero.”
So much for Mars, tomorrow morning.
But a half million years ago, when Earth’s half-apes gamboled in an eternal nightmare spring, did civilizations rear temples, forums and ocean cities across Mars? Have those peoples gone to dust, or perhaps burrowed underground to escape the bitter weather?
Krafft Ehricke, a top space researcher at Convair Astronautics in San Diego, very much doubts it. He believes that any planet originally able to clothe itself in oxygen and to rain down turbulent oceans of water would almost certainly be able to keep those elements in vast supply over geological leaps of time.
Nevertheless, Mars may well shock us from our provincial views. We must remember that here on Earth some germs thrive in purest sulphur, microbes generate in boiling Yellowstone springs. At Los Alamos our water-immersed nuclear reactors are often clouded by the micro-organism called Pseudomonas which survives radiation dosages 10,000 times stronger than those needed to kill a man. Similarly Mars, in its harsh natural laboratory, may have evolved fantastic chemical cycles that produce life forms heretofore unguessed.
All facts considered, however, our scientists may well tum to a more mysterious greenhouse world nearby. The surface of Venus, shrouded in mist, has never been seen. Some authorities still believe that this shroud results from titanic hurricanes of dust roaring over a bleak desert world. But recent Naval balloon-ascension observations have found the first traces of water vapor in Venus’ atmosphere, reviving the old theory that Venus is covered with water. The problem of landing on Venus then may be complicated by the discovery of an ocean that runs forever with no shore.
Given this single vast medium, the same elemental seas that we Earthmen carry as remembrances in our saline blood, it is reasonable to believe that with generation bringing forth generation for three billion years, fish kingdoms not unlike the societies of ant and bee might have developed in the Venusian depths. Unfortunately, the 50-foot radio telescope at the Naval Research Laboratory has found that radiation from Venus indicates a surface temperature of about 540°F. From this we can imagine millions of tons of water boiling up in oceanic storms to condense and fall in scalding rain.
“If this is true,” says Clyde Tombaugh, “Venus is not only a hidden planet. It may be a forbidden planet for manned exploration.”
Drownings and scaldings on one world, freezings and asphyxiations on another. Has our family of planets nothing better to offer us? Mercury, nearest the sun, has her noon side melting in 725°F. blast-furnaceings, her midnight side struck dead by utter cold. Jupiter, ten times larger than Earth and 317 times heavier, lies stunned beneath a hydrogen atmosphere 6,000 miles deep, an ice layer 13,000 miles thick. This dismal world would crush our rocket like tinfoil with an atmospheric pressure one million times greater than our own. Saturn, Neptune, Uranus, Pluto: the farther out the colder, darker, more desolate, as the story of life grinds to a halt.
Spurned by Mars, dusted off Venus, mashed by the gravities of Jupiter and Saturn, we will set our course for the stars.
Actually, no one man can live long enough to survive the journey from Earth to even the nearest star. Traveling far more slowly than the speed of light, even our fastest rockets may take hundreds of years to reach a single target. Yet once the journey becomes feasible, man will not be able to resist it. The nearest star being a lifetime or more away, we will have to prepare for a trip in which families will bridge the billion-mile gap with leaps of children, grandchildren and great-grandchildren. The abyss will know the burials of astronauts dead and jettisoned while their sons’ sons move on.
Unless we have a radio response to guide us, where will we go? By the time our star-ships are ready, we will have established great telescopes on our moon and on Mars. There, with atmospheric interference cut to zero and with visual clarity at its finest, we may be able for the first time to see families of planets obedient to distant suns. We will look for a planet revolving about a sun that looks old enough to have given its worlds time to rouse up life. We will try to detect a world like ours, whose atmosphere in the beginning was largely methane, ammonia, water vapor and hydrogen. That primitive world would have been needled with prehistoric lightnings and bombarded by a younger, more violent life-provoking sunlight.
We will look for a world which did the following for itself: 1) collected a thin sheath of water over at least a part of its surface; 2) for a billion or more years stirred this water into a broth of chemicals; 3) after untold trillions of fruitless combinations brought forth exactly the right complex of compounds, rich in proteins, needed to make up protoplasm; 4) somehow, in a way still not understood, built into this protoplasm the characteristic of self-reproduction that made it a living cell.
We will have to judge from a great distance whether a planet is too far out or too near its sun. A planet as close to the sun as we are should revolve at a good pace on its axis in a time corresponding to our 24-hour day. A planet turning more slowly would have higher temperatures dangerous to budding life forms. Also the cosmic rays that penetrate its atmospheric shell should not be too strong or too weak. If too strong, annihilation of life would follow. If too weak, the chemistry of the world would not be encouraged to put forth those remembrance-molecules we call life.
But let us say we calculate correctly, cross the galaxy and step from our rocket onto a sunlit world the incredible duplicate of Earth. Who, or what, will be there to greet us? Will it look human? Or will we be confronted by science-fictional creatures with multi-faceted housefly eyes and snakelike arms? Let us start with mankind and work down.
The alien creature at our rocket door might have eyes, ears, nose and mouth, might even have a skeleton on top of which would sit that appendage called “head” in which it would locate, through successive biological experiments, its main sensing organs.
How can we dare, imagine life like ourselves on another world, when even on Earth we find millions of creatures totally different?
“The problem is,” says Krafft Ehricke, “we do not even know what caused man’s differentiation from the primates. One thing is sure, however: we are constructed intelligently. If your eyes were on your knees or elbows and your brain remained where it is now, it would take 20 or 30 times as long for the brain to learn that a rock, say, was flying toward you. By the time the message traveled the long way from eye to mind, you’d be dead. You’d never know what hit you. It is therefore very functional for the eyes to be near the brain. The same goes for the ears and practically all our senses, as far as preliminary warning is concerned. One would assume that any higher intelligence on another world would need its sight, sound and smell located near its brain.
“Secondly,” Ehricke continues, “assuming a gravitation similar to ours, you must assume the need for a basic frame, a bone structure. It would not necessarily look like ours, but it has to be there. If this life form operates on oxygen or some other chemical system which uses gaseous intake, there would have to be certain conversion systems in the body such as our lungs and heart. For protection, these organs must be placed where the bone structure would serve them best—within the frame or otherwise shielded by bones. If our vital organs were located without protection in any of our limbs, accident might lop them off entirely.”