Chapter 10 Chapter 9 Life and Planets

The age of space travel has given us an entirely new sense and perception of the true nature of our home in the universe.Our eyes are wide open to the brother worlds, the other planets.At the same time, the most natural, obvious, and fascinating question arises in our minds: Is there life on other planets?Could there be any beings resembling man, whose intellect is at least as keen as our own, and who understand the wonder of creation? Ever since it was conclusively proven that the Earth is but one of many planets, the world has pondered the possibility of life in that faraway place.In the past, this question has fascinated a few scientists, philosophers and novelists; now it fascinates the whole world.It is precisely because everyone is confused that there is a so-called flying saucer.

A few years ago, newspapers published news that a flying saucer had landed in a remote area of ​​the American Southwest.From this legend spawned a character that is now a famous figure in cartoonists around the world: a little green man from space.The news in the newspaper said that the flying saucer had been partially crashed.It has a strange shape, the source of power is unknown, and what is even more strange is the material used to make the flying saucer.It was an extremely light substance, yet extremely strong; it was so radiant that where the parts were welded it was as if glass and steel had fused together.But it is the pilot of this strange machine that most arouses the reader's imagination.They were tiny humanlike creatures, only two or three feet high, and as green as grass.There were four of them, all dead, presumably suffocating our air with gases from our atmosphere that were poisonous to their bodies.These strange little people may have descended from Venus, the closest planet in space to us.

The whole story is, of course, nonsense, and its absurdity surpasses the legend about the monster in Loch Ness in Scotland, which some scientists think is worth investigating.However, there are important points in the UFO story that appeal to the popular psyche.The world always likes to believe that there is life in other worlds, and likes to describe other planets as if they are inhabited by intelligent creatures similar to humans like the earth.The roots of this belief run deep, and not just in the current interest in space satellites and interplanetary travel.Never since ancient times has there been such a strong emotional backlash in the world's view of science.The flash of the first atomic bomb deeply shook our hopes and beliefs. We had always thought that the path of science would lead to a better and safer life for all mankind.Many people now view science and scientists with distrust and even fear.Where has science taken us?Science has never been more closely entangled with international relations than at present.The anxieties of the Cold War rose and fell in rhythm with changes in people's feelings about their country's scientific superiority and backwardness.

It is from these sentiments that the myth of the flying saucer arose; it was an echo of the atomic bomb.Soon after the first atomic bomb was dropped, the story of the first flying saucer landing took place.Since then, UFO news has emerged in an endless stream.Millions of people believed in the existence of flying saucers, and indeed thought they were spaceships, piloted by intelligent races on distant planets. Most people don't think that those who come with flying saucers will harm people on the ground.The papers said they were kind; they seldom made hostile gestures.This species, spanning interplanetary space, must have long created a culture, technology, and science far superior to ours.But though they outdo us in scientific achievement, we can take heart: because these little green men are tiny little people compared to us.A large and bulky figure is a great compensation for any individual or any group with inferiority complex.

However, we do like that these little strangers are culturally superior to us.That is, they have solved the problems faced by the inhabitants of Earth today, especially the threat of self-destruction caused by the atomic bomb.From this point of view, the hope that mankind harbors seems to be the most important force behind the endless emergence of flying saucer myths today.Wouldn't it be wonderful if such a peaceful race came here to solve problems for us humans? The above are part of the reasons why ordinary people would shrug their shoulders if they were asked whether there was life in other worlds twenty or thirty years ago, and they would be fascinated by this matter today.But humans have long speculated about whether there are people on other planets, and what their shape will be.This kind of guessing is not just being confused about unknown things, or foolishly wondering about people who are not of my race, or making scientific conjectures.Its roots go deeper than that, in the deep contemplation each of us has about ourselves and our mission in the universe.

The question of life in other worlds remains at first a matter of faith, hope, and whimsy, not of scientific inquiry.But if we only look at the issue through the eyes of a twentieth-century scientist, we miss an important and interesting aspect of our story.The idea that the universe is inhabited by creatures is a dream with a history of tens of millions of years, which exists in the religions, myths, fairy tales and folklore of many peoples.It has captured the fantasies of poets and novelists and influenced the thinking of great philosophers.Even in our day, the question is as philosophical as it is scientific.

Our story begins thousands of years ago. At that time, people looked up to the power of nature and thought it was some gods, demons and ghosts.The blue sky seems to be only suitable for gods with boundless mana to live in, and some gods live in the underworld.Each celestial body itself becomes a god.The great sun god is the giver of light and warmth, but also the cruel creator of heat and drought, which can kill people.The silver moon is the god of fatness, and Venus is the god of love.In the minds of the ancient people, there are living beings on the stars; the stars themselves are more alive than the living beings on the ground, because the living beings on the ground will die, but the eternal stars are always the same.

The religion of the ancient Babylonians was the religion of the stars.Not only the stars are gods, but people on the earth will ascend to heaven to be with the gods after death.A little further from such dreams came the idea of ​​the Greeks, who looked at the stars with the curious eyes of mathematicians, and thus created the science of astronomy.They realized that the earth must be a sphere, and they also knew that the moon was not a disk embedded in the sky, but a world in itself.The Pythagoreans, as well as the great Greek philosophers Plato and Aristotle, postulated the existence of plants and animals on the moon, and believed that the inhabitants of this sister world were not these spirits and the like, but fellow spirits. All of us are sentient beings, having a living body.The man in the moon was a favorite subject of ancient writers; indeed, science fiction could be said to be an invention of the imaginative Greeks.

Plato's disciples believed that the planets in the sky were the abode and birthplace of the human soul.They believe that each soul inhabits a planet whose characteristics are best suited to that soul's mental and moral perfection.The ideas of Greek philosophy were transmitted into Christian teaching through the medium of the works of Origen, the godfather of the ancient church, who lived in Alexandria in the third century after the birth of Jesus.Origen believed that the earth was but one of the humblest worlds among billions that existed in the vastness of the sky.Those other worlds are the abode of the soul of man, where it is purified and perfected.These souls ascended from one planetary station to another, and finally reached the highest point, and finally reached perfection.In Origen's writings, these planets are a kind of purgatory, devised by the Creator to purify the soul step by step, culminating in the highest state, when morally and spiritually pure.Christianity's concept of heaven and hell is closely related to the above statement. Dante's Divine Comedy also expresses the life dreamed by the ancients. The world where that life lives is not the world we live in.

After three hundred years, the church announced that Origen was a heretic and prohibited the dissemination of his works.In the centuries that followed, the Church considered it absolutely inconceivable that another kind of human being existed in the universe.The Savior came to our world to save mankind; there is no other world like this in the Bible.The great theologian Thomas.Aquinas (Thomas Aquinas) firmly believes that God only picks out a kind of human beings and teaches them to be free from sin.Aristotle's writings became unquestionable dogma. It was not until the emergence of clear-headed thinkers in the Renaissance era that they cleared away the fog of the Middle Ages, opened human eyes again, and looked forward to the countless worlds in the sky.French philosopher and scientist Peary.Gassendi (Pierre Gassendi) not only revived the ancient Greeks' concept of atoms, but also revived the world's speculation about the universe inhabited by living beings.He sees no conflict between these views and the position of the Church.He wrote: Let us not commit the blasphemous hypocrisy of falsely thinking that God cannot create in other worlds spiritual beings equal to us, or even superior to us, which know their own world, Admire the opulence of these worlds, and praise the primitiveness of all things.

Gassendi's ideas are those of most of the creators of modern science: JohannesKepler (the person who discovered the laws of planetary motion); Dutchman Chris Tim.Huojian Si (Christian Hnygens) (the founder of the wave theory of light); and philosopher Emmanuel.Kant.About 1680, Hutchins wrote a book on the problem of beings in other worlds, in a way almost exactly like the way we modern people use to study this problem.He believes that the main conditions for life to occur may also exist on all planets, for example, everyone has day and night, air, water and land.If these conditions are met, says Hutchins, we must expect living beings to have been created on all planets, and races of very high intelligence capable of reasoning about themselves and the universe around them.Hutchins even thought that other stars had planets like the sun.The universe he had in mind was teeming with living things. But by the nineteenth century, much of the poetic and philosophical significance that science had had in the past had disappeared.Many scientists have become dispassionately reasoning judges who reject ideas that cannot be tested with absolute, mathematical precision.This is the proud Frenchman Simon.Pierre.Laplace (Simon Pierre Laplace), who improved Newton's celestial mechanics, proudly declared: In the universe he saw with mathematical concepts, there is no room for God, and God cannot even be regarded as a scientific Assumptions.This is an extreme view, shared by few scientists, but it expresses the tendency of science to concentrate its energies on the study of definite knowledge of physical things, the practical application of this knowledge to technical aspects, which now dominates us. world.By the beginning of the twentieth century, wild ideas about life beyond Earth had absolutely no place in science. Twentieth-century science still finds ways to sidestep human emotion and wishful thinking.With regard to life on other worlds, most scientists are skeptical.They don't think it's a scientific question, and they're probably right.At present, there is neither definite proof nor definite counter-evidence for this matter.The world can only guess, and science must avoid the habit of guessing.So this lofty question has been largely left to dreamers, sci-fi writers, and freelancers. But with improved satellites and the possibility of space travel, we are now seeing growing interest in the scientific community about the possibility of life beyond Earth.Scientists, like everyone else, love to speculate, and they are now well equipped in astronomy, chemistry, and biology to give some careful thought to this fascinating subject.In terms of expertise, we are vastly superior to our predecessors, whose thinking was almost entirely conjecture.Although we cannot yet expect to find a direct answer to our question, some noteworthy hints have been found along the lines of research. A living object is distinguished from inanimate things by its complex chemical structure.This structural complexity is due to the amazing kaleidoscopic variety of carbon atoms.Most common substances on Earth, such as water or salt, contain several types of atoms that combine to form what are called molecules.In the molecule of water, for example, two hydrogen atoms are joined to one oxygen atom.The molecule of sulfuric acid is made up of seven atoms: two hydrogens, four oxygens and one sulfur atom.But the carbon atom is the most outstanding of all atoms.It can combine with other elements to form huge molecules with various structures such as circle, chain, bundle or sheet.A large number of carbon atoms combine with hydrogen, oxygen, nitrogen and other common atoms in various arrangements to form the huge structures worthy of the name in the molecular world.Many of these massive structures contain up to hundreds of thousands of atoms, which together form what are known as organic molecules.These molecules are called organic because they were first discovered in living organisms.Proteins, amino acids, proteins, vitamins and hormones are common examples.For a long time, chemists could not artificially produce the various organic molecules mentioned above, and even today, the complex structures of these giant molecules are still largely unknown. If the building materials of the biological body did not have fundamental variability and complexity, life would not be as extremely colorful, diverse and efficient as it is now.An artist who has only a few terracotta tiles of different colors can only produce a few simple patterns.Life, like an artist, can work out of a set of things, numbering in the thousands, in every color, size, and shape, chiefly through the merits of carbon.Without carbon, or some other equally versatile element, our planet would likely be a barren, monotonous desert of the same rocks, mountains, seas, frozen wilds, and clouds.Carbon, more than any other substance, has been responsible for the vibrant, ever-changing biological world we know today. The diversity of life forms on earth is more complex than we can comprehend.Life is everywhere in the oceans, in the forests, in the air, in the polar regions and in the deserts.Its form ranges from the size of a whale to the size of a primitive organism, which can only be seen under a microscope of extremely high power.Life is very resourceful, it can adapt to a variety of environments.After hundreds of millions of years of development, plants and animals on the earth have been able to make their homes in almost all places on all layers of the planet's surface. This great adaptability of life is the main argument in support of the theory that life exists on other planets.Might not life, whatever it may be, find forms that can flourish in almost any situation, given plenty of time? Unfortunately, living organisms, for all their ingenuity, have limits, the most severe of which are those of heat.Living organisms can only exist within extremely narrow temperature limits.The temperature of water near boiling would kill all forms of life on Earth.Therefore, boiling water is the best way to sterilize: surgical instruments are absolutely free of germs and bacteria after being boiled in boiling water.A few very special species of animals and plants live in the pools formed by the thermal fountains; they can survive in waters of about one hundred and sixty degrees Fahrenheit, so hot that they scald human flesh badly.But these heat-loving creatures represent the maximum temperature limit that life on earth can tolerate.Most living things die when exposed to heat above 120 degrees Fahrenheit. The temperature range of life is neither narrow in high temperature nor wide in low temperature.Higher plants and animals die when exposed to low temperatures.Some microbes can survive in extremely low temperatures, but under those conditions they become inactive, hibernating.During the severe winter in the Arctic region, all land creatures that can survive, except humans, go into hibernation.They do not reproduce, are completely inactive, and merely preserve their lives.Even the process of decay, which is itself a living process, is effectively checked by the low temperature.So we store some food in freezers and refrigerators. Active and reproductive life can only exist in an environment with a moderate temperature.The huge organic molecules that are the building materials of life are very delicate and have little resistance to heat, and the complex organic compounds on which they depend are almost completely destroyed by heat.If we boil milk in order to sterilize it, the vitamin molecules also suffer, and the nutritional value is reduced.The method now used to sterilize milk is to raise its temperature to 160 degrees Fahrenheit. In this way, the germs are killed but the less heat-sensitive vitamin molecules are preserved. Low temperatures are less detrimental to the complex structures of organic molecules.But the ability of the frozen molecules to interact with each other is impaired.In living organisms, extremely complex reactions must be going on all the time.If the reaction is blocked, life itself is weakened and finally comes to a complete standstill. Temperature governs the biological world.The most profound changes occurred in the world of aquatic life; for example, if changes in ocean currents changed the temperature by even a few degrees, some aquatic life would die out entirely, while others would flourish.But when life developed into higher forms such as birds and mammals, the temperature constraints were even harsher.These organisms have gained a certain degree of independence from the temperature of their surroundings by developing the trait of warm blood.The body's temperature-regulating system is truly one of nature's most wondrous developments.If warm-blooded animals including humans did not have a natural thermostat, they would not have such keen senses, such quick reactions, such great endurance, such effective nervous system, and such a great mind.Just think about it: the living matter in the human body has been kept at a temperature of exactly ninety-eight point six degrees Fahrenheit since the beginning!This uneasy consistency shows in itself how important it is to maintain the proper temperature in the existence of higher organisms. Therefore, when we set out to search for life in the deep space of the universe, we must look for matter that exists at a moderate temperature.But we find that this requirement is difficult to meet in nature: almost all substances in the universe exist at extremely high or extremely low temperatures.About half of the matter is tightly packed in the cloud-like bodies of the stars, which reach temperatures of thousands or even millions of degrees.The other half of the matter in the universe is scattered very sparsely, becoming individual atoms and tiny dust particles, floating in the space between the stars.The temperature of these dust particles is extremely cold: only about minus 450 degrees Fahrenheit.But a tiny fraction of the cosmic matter condenses into rare objects we call planets.These objects, distinct from the vast majority of cosmic matter, orbit stars that, in some instances, keep the temperature of the planet's surface somewhere between the extremes of maximum and minimum.Thus, this planetary traversal in space gradually became warmer; for the creation of the planets was the first great step towards the creation of life. Assuming that the chemistry of life must be essentially the same everywhere in the universe, we can measure the chances of life with a thermometer when we get to other worlds.Our own planet is truly the norm: it's the ideal place for life to flourish.Our distance from the sun is just right, and most of the ground gets enough, but not too much, heat for life processes.Most of the Earth's surface, including the land, oceans, and lower layers of the atmosphere, has always been in a narrow temperature band that allows life to exist.Based on what we know so far, any other world must be able to provide conditions similar to those on the earth in order to raise plants and animals similar to those on the earth. The situation on the moon is completely different from that on the earth.There is no atmosphere on the moon at all.During the day, the sun's rays fiercely cast on the exposed rock and dry dust of the moon's rugged surface; at night, the temperature plummets to around minus 200 degrees Fahrenheit.The mass of the moon is too small to attract a ring of atmosphere, so there can be no exposed water surface. Even if we could, by some miracle, give the moon an atmosphere like that of the earth, and fill the recesses of the moon's surface with water, creating oceans, the moon would soon lose both things.The motion of the atoms and molecules of the air on the moon will be greatly accelerated by the heat of the sun, just like the air on the earth.Some flying particles on the top layer collide with other flying particles. With a sudden increase in speed, they can escape the gravitational force of the moon and rush into the interstellar space.This also happens in the earth's atmosphere, but the earth's gravitational pull is six times stronger than that of the moon; therefore, the moon's atmosphere is depleted much faster than the earth's.In just a few thousand years, the entire atmosphere of the moon will be gone, and the lunar ocean, which has been evaporating for a long time, will disappear with it.Like Mercury among the planets, the moon cannot keep a layer of air as an outer cover due to its small mass and insufficient gravitational force. It is strictly incorrect to say that there is no atmosphere on the moon.There may be a few isolated particles of heavy, slow-moving gas on the surface of the moon, which may be called the atmosphere.But the few wandering particles are not worthy of the title of air. Those of us who have lived at the bottom of the vast sea of ​​air all our lives can hardly imagine how to travel in a world without air.The first explorer to land on the moon took a handful of fine lunar dust, threw it up, and it fell back down like a batch of pebbles.There is no air for dust to float.By the same token, the explorer would have discovered that if a feather and a piece of lead were dropped at the same time, they would both fall at the same speed but not as quickly as when a piece of lead was dropped through the air on the earth. , because the gravitational pull of the earth is stronger.On the moon, our astronaut will also perform an amazing feat: he can throw a soft tissue a mile away!There is no air resistance on the moon to stop the paper towel, and once it is thrown, the gravitational force that pulls it down to the ground is very small. Without water and air, the moon has no means of softening the extremes of day and night temperature.On Earth, the atmosphere and oceans store the heat of the day and release it slowly during the cold nights; so we don't feel bitterly hot during the day and bitterly cold at night.But on an airless moon, temperatures rise above boiling at noon and drop precipitously below minus two hundred degrees Fahrenheit after sunset.For hundreds of millions of years, during its regular cycle of orbiting the earth once a month, the moon seems to experience temperature fluctuations of about 400 degrees Fahrenheit. Nothing resembling the species known on Earth could survive the Moon's brutal conditions.The terrible heat and cold on the moon cannot be endured by any living organism; hot and cold, cold and hot, still less can be endured by any organism.It seems safe to say that our satellite is a lifeless world, every inch of it is barren. The moon is much smaller than the earth and all other planets.Is life possible on those other larger worlds? First look at the closest planet, Mercury.Although its diameter is one and a half times larger than that of the moon, its mass is too small and its gravitational force is weak enough to maintain a ring of atmosphere and water above the surface.Moreover, Mercury is only a third of the distance from the sun to our earth (and the moon), and the heat from the sun hits the surface of Mercury so intensely, in fact, that it melts tin into a liquid.Of course, we are talking about the situation on the side of Mercury facing the sun; the other shady side is correspondingly cold.By any standard, Mercury is a place of extremes.According to telescope observations, Mercury does not revolve around its own axis like Earth does.One side of Mercury always faces the sun, just as our Moon always has the same side facing Earth.Since Mercury has no rotation, the sunny side will always be roasted, and the shady side will always face the dark and heatless deep space.Mercury has no atmosphere to transfer heat from the sunny side to the shady side.Therefore, the temperature on the dark side must be close to absolute zero, which is about 450 degrees below zero on the Fahrenheit scale. In this way, Mercury is even less amenable to life than the Moon.Living organisms can exist on this planet only under the protection of artificial means.It is unimaginable that life can develop under such a bad temperature situation.Mercury is a lifeless world, another desolate ball of stone, both luminous and frozen. The second planet, numbered in order, is Venus, the lovely dawn and evening star.Its distance from the sun is about two-thirds of the distance from the earth to the sun.In terms of size, Venus and Earth are true twins: its diameter is only about 4 percent smaller than Earth's.The solid ball of Venus is often covered by a thick white curtain, never to be revealed.The world has always thought that this dense shadow was composed of clouds, as clouds are familiar to the inhabitants of the earth. When talking about the past geological ages, Venus is often compared with the earth.The greater amount of solar heat to which Venus was supposed to produce vast forests, fed by warm, moist air and almost inexhaustible rains.The entire surface of Venus may be covered by vast meadows and swamps, populated by gigantic lizard-like animals, as if they existed in the age of the great reptiles on Earth.However, all of the above ideas may be pure speculation.Using a spectroscope to study the upper layer of the atmosphere of Venus, no water vapor can be found, and no oxygen is found at all.The air on Venus contains large amounts of carbon dioxide, which plants may use.But the presence of this gas could heat the surface of Venus to deadly heights.While the temperature at the top of the shadow has been determined to be around zero degrees Fahrenheit, the underlying layers of carbon dioxide gas are much hotter.The carbon dioxide traps the heat of the sun, keeping it in but not out, like the glass tiles of a greenhouse.The temperature in the deepest layer we can measure is about 125 degrees Fahrenheit, which implies that the surface temperature of Venus is at least 300 degrees Fahrenheit. At such high temperatures, no life form known to us can exist. .Therefore, Venus must not be home to any of the fabled little green people! Leaving Mars aside for a moment, let's look at some of the more distant planets in our solar system: giant Jupiter, beautiful, ringed Saturn, green Uranus, Neptune, and distant Pluto.These molecules of the solar system can be written off as a home for living things: because they are too cold.They orbit the sun at great distances, away from the heat of the sun enough to support life, forever trapped under thick ice and frozen poisonous gases of methane (methane) and ammonia (ammonia).Life must not unfold in these frozen worlds.Higher organisms die instantly in this freeze; even hardy bacteria and spores cannot survive, and are completely immobile before death. No wonder that, of all the known worlds in the sky, we pin our hopes on Mars as the most likely place for life.Now the red planet is the focal point of ancient dreams.In fact, Mars has been the focus of dreams since an astronomical event more than eighty years ago. The year was 1877.At that time, the skill of making telescopes was well developed, although the telescopes made were not as huge as they are now.Before the 1870s, astronomers had concentrated their attention on the motion of celestial bodies; by this time they had concentrated more on the physical properties of the stars and planets.Milan astronomer Giovanni.Giovanni Schiaparelli was particularly interested in these stars, and one night he made an exciting observation.On the reddish surface of Mars he saw, or thought he saw, criss-cross layers of very thin straight lines leading to darker regions.These lines are seen only occasionally, when the Earth's atmosphere is least disturbed by things that would be a hindrance to astronomers.Schiaparelli called these thin lines canals, just as the black patches on the moon are called seas. The term canal, which is rich in meaning, has greatly excited the world.The canal suggests something not created by nature but by man.Canals on Mars sparked speculation about the possible existence of Martians, and even today, the idea continues. At the beginning of this century, there was an American astronomer Percival.Percival Lowell was a big proponent of the idea.He contributed to the creation of the now world-renowned Lowell Observatory, located near Flagstaff, Arizona, for the study of the planets, and Rowell himself devoted his life to the study of Mars.Long-term observations seemed to confirm his first fanciful notions.He noticed that vast regions of Mars seemed to change their color and shape according to the local seasons.In winter, these areas will show a yellowish tint, which turns green or blue-green in spring, turns brown again in the second half of the year, and then returns to yellowish.It seems that whenever spring comes and the snow cover at the poles melts away, the canal becomes clearer.In autumn and winter, when the polar ice caps form again, the canal is almost invisible. Rowell published a book in 1907 that became very famous, entitled Mars as the Abode of Life.His observations are described in the book, and an explanation is given that Mars is inhabited by intelligent races, who are fighting valiantly against the problem of dwindling water resources.He believes that the Martians established a large-scale irrigation system crisscrossing their planet, all over the earth.The snow water formed by the melting of the ice caps at the poles is a source of water for them.Canals bring this poor and precious water to warmer regions every year to irrigate the fields. Rowell's idea was warmly welcomed by the world and many of his colleagues, but most astronomers were extremely skeptical.Of course, neither confirmed nor refuted, because neither is possible.Rowell's theory can only be regarded as pure conjecture, and the correctness of the conjecture cannot be judged until more reliable facts are available.Certain facts may not be known until the day when the first spacecraft lands on Mars. Rowell died in 1916. Later, the climate and atmospheric conditions of Mars were better understood, because more extremely sophisticated instruments were used in conjunction with the telescope.New information makes Rowell's Martians appear to be entirely non-existent.It has been found out that there is no oxygen in the air on Mars. Without oxygen, advanced organisms seem to be unable to live, and there is no way to produce them at all.The climate on Mars is also hostile to living things.At night the temperature dropped to almost a hundred degrees below minus Fahrenheit, and it was only around noon, near the equator, that the temperature rose above freezing, and this lasted no more than an hour or two.No animal on Earth can survive such drastic daily temperature changes.Conditions on Mars are so harsh that geologists cannot believe most of the speculation about Martians. The question of whether there is life on other worlds is generally regarded as the domain of astronomy, and the scientific books and articles on the subject are almost without exception written by astronomers.But one book is an exception, by the biologist Herbertas.Hubertus Strughold, entitled The Red and Green Planet, A Physiological Study of the Possibility of Life on Mars .The book's scientific approach gives the studious and thoughtful a new perspective on the question of life on Mars.Even the most primitive animals could not survive on Mars, Stighold said, because there would be no oxygen to support their metabolism.Oxygen is an essential element of life, without it, one dies.Plants also need to breathe oxygen, and the atmosphere on Mars doesn't contain nearly enough oxygen to meet the needs of the plant kingdom.Plants, however, are able to carry out a special chemical process by which they can survive, which animals cannot do: photosynthesis.斯揣格荷爾德博士說明：植物藉這種巧妙的作用，能應付火星上有害的情況。 光合作用是個卓越的生命製作法，藉著葉綠素的行動而發生，葉綠素是一種複雜的化學物質，具有鮮艷的綠色。這個製作法所用的原料是水和二氧化碳，而動力是陽光。植物吸收陽光的能，在葉綠素的節制下，水和二氧化碳的分子分裂為構成它們的種種元素，即氫、氧和碳。這些元素重新組合，形成所謂碳水化合物，即糖、澱粉和脂肪。這些產品給植物利用來建設它們的身體；氧氣過剩了，便釋放到空氣中。地球的大氣層，其實是個巨大無比的大儲藏室，儲存自由氧是從古以來的植物產生的。儘管大量的氧不斷受到消耗，植物王國的化學活動總能夠使空氣中的氧氣儲存量始終保持同一水準。 像動物一樣，植物也需用氧來進行自己的新陳代謝，在地球上，空氣裏含有充分的這種賦給萬物以生命的氣體，固流上下四方，供應一切活東西。火星的空氣裏卻沒有自由氧，而且看來似乎就連植物也不能在那兒生存，因為它們時時刻刻需要呼吸自由氧。但在這個關鍵問題上，斯揣格荷爾德提出了一個有趣的想法。他並不認為高等植物有可能存在於火星上，因為事實已經表明：這類植物不能放在缺氧的空氣裏，是會凋謝殞歿的。而且，這些植物也會給火星上晚間的極低溫度凍死。斯揣格荷爾德所著眼的是最低級的植物，它們特別具有適應性，能抵受極冷的天氣，斯氏研究這類植物怎樣能夠在完全沒有氧的大裏生存與生活。 他所著眼的植物是地衣，那是一片片灰綠色的植物，依附於地球的高山的裸露岩石上。地衣是兩類植物的結合，一為菌類，一為藻類。菌類構成地衣的身體，使它具有海綿一般的結構，能吸收並儲存水汽；藻類卻含有葉綠素，進行光合作用的過程，產生碳水化合物和氧。但最有趣的是：構成地衣的身體的材料，具有數不清的細胞，裏面灌滿空氣。這些小袋袋裏的空氣包含頗大份量的氧：事實上，這種植物內部的氧比外面同樣高積的空氣裏所含的氧多些。我們可以說，這些地衣具有它們自己專用的大氣層，它們就把藻類產生的氧儲存於這種大氣層之中。因此，斯揣格荷爾德斷定地衣確實能夠生存於火星的空氣中，表面看來，這種空氣是沒有氧的。 能讓地衣滋長的一切必需條件，火星都具備。那兒有陽光可供光合作用之需，那兒也確實存在著二氧化碳和水。地衣呼吸所需的氧，由它們自行生產。但這種氧並不釋放到空氣裏去；地衣不能夠浪費這種珍貴的氣體。它們把氧儲存於自己的身體內。 在火星上一到夜裏就沒有陽光推動光合作用的過程，因此，白天生產的並儲存起來的少量氧，不足以支持地衣熬過漫漫長夜假如不是極度寒冷的話。的確，酷烈的寒凍會把別的一切植物都殺死，卻幫助了地衣為生存而掙扎。在晚間，地衣凍得完全入於冬眠狀態，一切生命過程幾乎完全停頓。於是地衣幾乎完全不需要動用氧。熬過幾個鐘頭之後，早晨來臨，氣溫回暖，地衣恢復活動，重新進行光合作用，供應自己呼吸所需的氧。 斯揣格荷爾德博士用實驗上的證據支持自己的看法，實驗是在德克薩斯州聖安通尼奧附近的航空與太空醫學中心進行的。他建立了所謂火星植物培養槽（這個名稱相當於陸地動植物培養槽），是個密不透氣的玻璃箱，內含無氧的大氣，正是大家認為火星上的大氣那樣。這個火星植物培養槽放在一間黑房裏，每隔一定鐘點由燈光照射著它，相當於火星上所受到的太陽輻射。當這個培養槽受到照射時，它的溫度也用人工方法造成一定的周期，有一段時期是加熱，接著便將它冰凍，彷彿火星上的晝夜循環。在這個培養槽裏，斯揣格荷爾德博士養了少許地衣，是他親自到新墨西哥州的火山熔巖層上採集的。這些卓越的植物到今天不但安然抵受了兩年多的酷烈處理，而且居然傳宗接代，大為滋榮。 斯揣格荷爾德博士對於火星上的生命的看法，可能代表了真正的情況。這些看法是同生物學上已知的事實符合的。活著的東西自有辦法適應於環境狀況，而且極力利用這種狀況。在我們地球上，生命是朝外向的，同友好的大氣層自由交換；火星上的生命卻是朝裏向的，把有害的環境阻擋住了。火星絕沒有給注定為高級生命形式的家鄉；這個紅色行星居然能讓生命儘管是最低級的生命存在，已經是件很了不起的事。 這樣看來，縱然把火星算上，太陽系的九個行星中也只有一個即地球具備著種種條件，有利於各式各樣的、繁榮旺盛的生命形式。宇宙之中居然存在著我們這麼一個行星，具有種種的優點，確實是件教人驚詫的事：我們地球的位置離太陽不遠也不近，因此氣溫不太熱也不太冷；我們的大氣層裏富於氧和二氧化碳；更難得的是，我們有充足的水的供應，它又是液態的。由我們所知道的諸行星的一般情況看來，別的任何一個行星很不可能以一身而兼備地球所具有的諸般優良的特色。 科學每每同詩人的夢想作冤家對頭。已知的事實硬是不容我們相信火星上繁生著品類萬殊、五色繽紛的生物：各種花、樹、魚、鳥和人。假如我們有朝一日去到火星上，我們說不定頂多只能發現一片片原始而醜陋的生物生長在枯寂荒涼的土地上。然而單是這種東西已足以使科學家興奮之至。儘管是下等的地衣，也具有生命的火花。即令是最低級的生命形式也滿身都是祕密，科學界還得要花很久時間才可將這些祕密完全揭露假如這是可能辦到的。一塊無生命的石頭同最原始的活細胞之間的差別，大大超過了這個細胞同人的差別。科學不會弱於詩人或講道者，它同樣知道生命現象確實是多麼奇妙，若是真能在另一個世界裏發現奇妙的生命火花，那就會比往昔的人最異想天開的夢想更激動我們的心靈、更令我們驚奇了。