The Earth and Life in It

The Earth and Life in It By DR. JOSEPH F. MERRILL Church Commissioner of Education THE strangest thing about the earth is the people in it. Not that we are all strange peo- ple, but we do not positively know that there is another single orb in the heavens that boasts of any liv- ing inhabitants." In our universe there are thousands of millions of stars — suns, many, perhaps, being surrounded by solar systems similai to our own. But of this we can never be certain, for these planets, uif they exist, are too small, far away and dark, ever to be discov- ered by any means within human power. No telescope or other instrument ever made would reveal the Earth or Jupiter to us if we were gazing from even the nearest star, 4 light-years' distant. And surely none of the visible stars are habitable, for they are much too hot, their temperatures being much higher than any known fiery fur- nace. The temperature of our own sun varies from ten thousand de- grees at the surface to forty millions at the center. Similar temperatures exist in other stars. And of the seven other planets in our solar system none has condi- tions so favorable for life as we know it as does the earth. The following table of data of our solar system, after Professor F. R. Moulton, is interesting in this connection: Planet Distance from Sun Length of Year Mean Diameter Density Water- 1 Mass Earth -1 Mercury 36,000,000 miles 2.9 months 3,009 miles 4.5 (?) 0.05 (?) Venus 67,200,000 miles 7.4 months 7,701 miles 4.9 (?) 0.81 (?) Earth 92,900,000 miles 1 2 months 7,918 miles 5.53 1.00 Mars 141,500,000 miles 22.6 months 4,339 miles 3.58 0.11 Jupiter 483,300,000 miles 11.9 years 88,392 miles 1.25 314.5 Saturn 886,000,000 miles 29.5 years 74,163 miles 0.63 94.1 Uranus 1,781,900,000 miles 84.0 years 30,193 miles 1.44 14.4 Neptune 2,791,600,000 miles 164.8 years 34,823 miles 1.09 16.7 "CROM this table it is seen that the planet Venus, two-thirds the distance of the earth from the sun, is the only planet comparable in size — (volume and density) — to the earth. Conditions on Venus may be favorable to life like ours, but the surface of Venus no human eye will ever see because it is en- veloped continuously in an impen- etrable blanket of clouds. But suppose Venus or some other planet is peopled. How should we ever know it? To communicate with them they would have to un- derstand our language. But our tongue would be utterly unknown to them. Idle fancy, however, has been frequently indulged in specu- lating about the inhabitants of the planet Mars. The length of the day there is not much different from that on the earth and its seasons resemble those of the earth, though the year is nearly twice as long. As shown by the table, Mars is about 48 million miles farther than the earth from the sun. Hence it is colder there than

The Improvement Era For November, 1929 45 here. By certain methods practiced by physicists and astronomers, the temperature of heavenly bodies may be measured. At noon the temperature at the equator of Mars is about 50 degrees Fahrenheit; but at sunset this temperature falls to the freezing point and reaches about 50 degrees F. below zero at midnight. Further, spectroscopic methods show that the air on Mars is rare, containing very little water- vapor and only about one-sixth the oxygen of the earth's atmosphere. Who of us could live in a place so cold and forbidding where the air is so rare and so dry? The giant Jupiter and the three planets be- yond are much less dense than the earth. Probably like many of the stars and the sun they are not even solid bodies — therefore wholly un- inhabitable. "|SjOW, some of the stars have -^ solar systems similar to ours — hence habitable worlds probably exist in distant parts of the uni- verse. But for this view specula- tion is our defense — we can never be certain. Strange, is it not? Astronomically speaking, the earth is only the tiniest speck in the universe and yet science says it may be the only known dwelling place of human beings — of man, whose intelligence comprehends the uni- verse which is so vast that it takes light, traveling at the rate of 6 trillions miles a year, (this distance is called a "light-year"), hundreds of thousands of years to cross it. Let him who questions the power of human intelligence study mod- ern astronomy and particularly read the story of the discovery of the planet Neptune, the most distant member of our solar sys- tem, a member that no naked eye has ever seen because of its distance and dimness. It was the great Newton who discovered the key by which the mysteries of motions of celestial bodies have been un- raveled. His tomb in Westminster Abbey, where England buries her greatest men, carries this* epitaph: "Mortals, congratulate yourselves that so great a man has lived for the honor of the human race." Factors Upon Which Life Depends T\7 HY is it probable that human W life does not exist on any other member of the solar system? The answer will be plain when we enumerate some of the essential factors upon which life depends — equable temperature, light, water- vapor, atmosphere. How sensitive we are to changes in temperature! D R. JOSEPH F. MERRILL is one of the highly trained men of the United States, and the Church is fortunate in having him as Com- missioner of Education. He studied in the East, after graduating from the University of Utah, and took degrees from the University of Michigan and later from Johns Hopkins University. In addition, he has spent five summers at Cornell and the University of Chicago. Dr. Merrill was director of the School of Mines and Engineering at the U. of U. prior to being called to his present position. For a number of years he was in the presidency of Granite stake, and is now a member of the General Board of Y. M. M. I. A. Life depends upon vegetation. And vegetation thrives only between the temperature limits of 14 to 132 de- grees Fahrenheit. But in measuring temperature the physicist com- monly begins at "absolute zero", a point 459 degrees below the zero of the Fahrenheit scale. The rea- son for this is that heat depends upon molecular motion, but this motion entirely ceases at the "absolute zero." So, expressing on the "absolute" scale the vegeta- tion temperature ranges, we have 473 to 591 degrees, which is only 1 1 per cent, above or below the average temperature, 532 degrees. For life to thrive the temperature must stay within these narrow limits. But what keeps it from exceeding these limits? Science answers, "the sun, the air and the water." If there were no air on the earth the noon-day sun would send the temperature up to the boiling point of water, but before the next morning it would get cold enough to freeze the mercury in the thermometer bulb. But this great change in temperature does not occur. Why? Because of the tempering effects of the air and the water-vapor and clouds which it always contains. V\ URING the day the atmosphere ^ absorbs some of the heat of the sun, the amount depending on the density and water-vapor contents of the air. After sunset the earth radiates out the heat received from the sun. But this process of losing heat is more or less slowed up by the enveloping atmosphere which acts as a blanket and keeps the heat in. The more clouds and water- vapor in the air and the greater the atmospheric pressure the more effectively the blanket acts. In the spring frosts do not occur on cloudy nights. Desert travelers and mountain climbers know that in high elevations where the air is light and dry the difference between the day and night temperatures is very great. The sun's rays pass through a vacuum and all transpar- ent media without heating them. Thus in high altitudes direct sun- shine is warm but it is cool in the shade. Where there is no absorption of the sun's rays there is no heat- ing. But the moment the sun goes down and heating by absorption stops, then cooling begins and dur- ing the night all the heat gained during the day may be lost. A Digression on Radiation "THE process of heating and cooling is called radiation. The sun sends its energy out into space, not in the form of heat at all, but in the form of waves which pass out through space with the tre- mendous speed of 186,285 miles per second. If the waves are absorbed, their energy is changed into heat and the temperature of the absorbing medium may rise. We say may rise. Let us explain. Already we have said that when the motion of the molecules of a body ceases there is no heat in the body and the temperature has reached the "absolute zero" — 459 degrees below the zero of a Weath- er Bureau thermometer. If there is molecular motion, then there is radiation — waves carrying away energy with the speed of light. If the body absorbs radiant energy faster than it radiates it, the tem- perature rises; if slower, the tem- perature falls; but if the gains and losses are equal the temperature remains constant. Obviously the higher the temperature of a body the faster it radiates — sends out energy-carrying waves. But these may not be light waves. Indeed even the sun's radiation is not all light waves. It contains ultra- violet waves — too short to give us; the sensation of light — and infra- red waves — those too long to excite vision. In general the higher the temperature of a body the greater is the proportion of short, or light- producing, waves in its radiation. But let us keep in mind the fact that above the "absolute zero" all

46 The Improvement Era For November, 1929 bodies radiate waves, relatively long ones at low temperatures and more and more shorter ones as the temperature rises, so that finally the body may become hot enough to emit some light-producing waves along with its invisible radiation. The body is then at least red-hot and will be hotter when shorter waves are radiated. The entire radiation from an incandescent body like the sun consists, there- fore, of waves of many different lengths, those giving light sensa- tions being very short — about one- fifty-thousandth of an inch long. But long or short the waves are all of the same kind and travel with the same speed through space. Radio waves, relatively very long, are also of the nature of light- waves and have the same speed. Radiation and Plant Growth 1 "'O return from whence we digressed. The radiant energy of the sun is enormous. Even though the earth is nearly 93 mil- lion miles away, on a square yard exposed perpendicularly to the sun's rays radiant energy is received at the rate of one and one-half horse-power — enough to heat every minute six ounces of water to the boiling point. The average rate for the twenty hours — periods of darkness as well as sunshine — is three-eighths of a horse-power per square yard of the earth's surface, or the surprising amount of 1815 horse-power per acre. It is upon this radiant energy that all life depends. Sunshine is requisite for plant growth. Plants feed animals and plants and ani- mals feed man. Plants do not grow in the dark. Under the in- fluence of sunshine their leaves inhale carbon dioxide gas from the air, which, in combination with the water and chemicals brought up from the roots by the sap, is con- verted into complex compounds of carbon — the life-substances of the plant. Literally then the leaves are the chemical factory upon which all earth-life depends. Curi- ously enough they inhale carbon Keep on the Way You are Going, BY JOSEPH S. PEERY RECENTLY Mr. D. A. Skinner, Secretary of the Chamber of Commerce of the United States, remarked to a L. D. S. missionary: "Keep on the way you are going. You beat the world in turning out more and better leaders." A lady remarked: "How do you produce such fine, clean young men for missionaries?" The answer is given: 'That is what this Church does to all who observe its teachings. It uplifts every person who is active." Christ said, 'Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? Even so every good tree bringeth forth good fruit." Our young people are taught correct principles from in- fancy and are given opportunities to apply this knowledge. They develop through their activities. As they obey and work they grow. They are doing the work given them by the Master, and he directs them with his spirit. Naturally they are enthusiastic because they believe with all their hearts in the thing they are doing, and working thus they are encouraged from on high. Joy comes as a reward of their endeavors. Consequently they are earnest salesmen of the divine message. The hearers feel this spirit, and, unless very much prejudiced, are impressed by it. A lady said, "I am gripped with your message." Why shouldn't this be the case when the Almighty is our leader and teacher? All eternity calls to us: "Keep on with the good work. It means salvation to yourselves and to all who hear you." No wonder with such an impulse, such pure teachings, such opportunities for every member, that leaders are produced. Yes, let us keep on the way we are going. It is God's way, and we cannot improve on it. dioxide, the waste of animal breathing, and exhale oxygen, the necessary element inhaled by all animals — complementary reciproc- ity, we might call the process. HTHUS the growth of plants is due to a marvelous but little- understood chemical process. Man with all his learning, cunning, and skill, cannot yet duplicate the process and there is little hope that he shall ever do so. This process requires an equable temperature, sunlight, water, carbon dioxide and other chemicals — elements and factors all well known. But the secrets of the process Nature has to date kept securely locked from the prying eyes of her inquisitive sons. We know the conditions for plant growth and for life in all its varied forms and hence we are slow to believe that life exists where the conditions are greatly different than they are here in the earth. We say therefore that life may exist on the planet Venus, the October evening star of 1928, 1930, and 1931. On Mars, the fiery-red planet next to the earth but on the far side from the sun and the October evening star in 1929 and 1931, some low forms of life may exist. But man would certainly have a tough time trying to live there. The other planets of our solar system do not support life as we know it. TX7E have spoken of life "in the ** earth." The reason for this will be apparent when it is recalled that the atmosphere is a part of the earth and one of the elements ne- cessary for the existence of life. Some heavenly bodies like the moon have no atmosphere because gravity there is too low to hold air and water-vapor to the surface. So on the moon the temperature difference between mid-day and mid-night is surprisingly great, boiling temper- atures at noon, but extremely in- tense freezing at midnight, 200 to 300 degrees below zero. Further, the lunar day is nearly 30 times the length o£ ours. Hence there is no life on the moon. Science says there is probably no human life in our solar system ex- cept in the earth. If there is any elsewhere in the universe science can never find it out. But if there is, these people are not near neigh- bors, for their planet is at least as far away as the nearest fixed star — four light-years, or twenty- four trillion miles. We shall never quarrel with them.