Show 10 0 How AIR Prevents the SUN f f from BURNING Up the EARTH i t 1 r- r TN N much the same way vay that the thick steel i r IN I armor that covers a battleship turns aside J shells of heavy calibre so does dOCS the atmosphere r R that surrounds the earth save this globe from a J fiery fate by deflecting the suns sun's intensely burning burn burn- ing rays ays Astronomers tell ten us that about 40 per I cent of the suns sun's rays are reflected away into I 4 L space ace by the earths earth's atmosphere Of the remaining remaining remain- remain ing jag 60 per cent one-fifth one is absorbed by water f- f vapor suspended in the atmosphere between sea sealevel b level and anti an elevation of five miles while two- two fifths are arc absorbed by clouds lying one or two miles above the surface As a result only 20 per k tent cent of the rays that enter the atmosphere act act- actually K na tally y arrive at the surface of the earth These 1 j yV estimates are the results of measurements of the Fr fr r r- solar radiation made at sea level and on mountain mountain moun- moun tain tamn heights 0 f The rays heat-rays that are radiated from the c earths earth's rth's surface also suffer powerful absorption AU- AU I y i by the water vapor and carbon dioxide in the atmosphere explains Isabel M. M Lewis of the d United tinted States N Naval val Observatory writing in Science and Invention According to estimates 1 V made fully half the radiations from the earths earth's surface are absorbed by clouds and three-fourths three of the remainder by water vapor and carbon di dioxide dioxide dioxide di- di oxide in the atmosphere so that barely 10 per percent cent of the earths earth's radiations escape directly into space though by continual radiations from t k one place to another within the atmosphere the heat gradually seeks higher levels and tends to rr escape II Were it not for this blanketing effect due almost al- al almost al al- t. t most entirely to the water vapor and carbon di dioxide dioxide di- di dioxide oxide in the atmosphere preventing too rapid radiation into space as well as the effect of the u atmospheric currents which are a most powerful T Y i factor in equalizing the extremes of temperature all aU over the globe it is very doubtful whether f. f k either animal or vegetable life would be found to any extent upon our planet It is well known 1 that there are much greater extremes of heat and cold between day and night on the mountain It peaks than in the valleys owing to the greater rarity of the atmosphere and the comparatively V. V 1 small amounts of water vapor and carbon dioxide I i i At the earths earth's surface the atmosphere measured measured meas meas- o tired by volume contains 78 per cent nitrogen h and 21 per cent oxygen with less than 1 per percent cent centt and minute 1 cent argon quantities of helium t i i R krypton neon and other rare gases as well wen as such impurities as soot ammonia etc ete It conJ contains con con- J 0 u thins in in addition water vapor and carbon di di- di oxide These two constituents of the he atmosphere 1 ti 1 r represent scarcely 3 per cent of its weight but they are absolutely to all living organ organ- organisms organisms isms upon our planet k yV V It is the tempering effect of these two compounds compounds com com- 1 If pounds in the atmosphere that protects us from 3 t the great extremes of heat and cold th that ti would VV V otherwise exist on the day and night side of our planet planet It is also well known that early frosts will 1 V not occur when there is much water vapor in the theair theair air or when clouds are plentiful Nitrogen and oxygen which occupy 99 per percent cent of the volume of the earths earth's atmosphere have practically no absorbing effect on the earths earth's radiations but they do strongly absorb and scatter scatter scatter scat scat- ter the short solar rays in the blue and violet and therefore produce the intense brightness and nd characteristic blue color of the sky When the suns sun's rays enter the earths earth's atmosphere atmosphere atmosphere atmos atmos- phere they are diffracted or broken up to a certain certain certain tain extent by passing fT from m a rarer to a denser medium The short blue bine and violet rays suffer the greatest diffraction and are largely lost in inthe inthe inthe the upper atmosphere while the long orange and andred andred red rays penetrate to the lower depths depths of of the earths earth's atmosphere The beautiful sunset hues and the reddish tinge so characteristic of the sun and moon when rising or or setting is due to the breaking up of the rays by the tho dense lower strata of the tho atmosphere and the trapping of the tho blue and violet rays by bythe bythe bythe the atmosphere Were it not for the scattering and diffusion of sunlight by the atmosphere the sky y would al always always always al- al ways be inky black and the stars and solar corona would always be visible in the daytime All An shadows shadows shadows shad shad- would be harsh and as black as the inky y sky Without the atmosphere there would be no winds no clouds no rainfall no rainbows no twilight no beautiful sunsets no living beings The dry and barren surface of our planet would be constantly pelted with the meteorites and meteoric meteoric meteoric me me- dust that are now almost entirely consumed consumed consumed con con- by friction with the atmosphere and only in exceptional cases reach the earths earth's surface The extremes of temperature between day and night would be intense The 1 blistering heat of a torrid day would be followed by the frigid cold of an arctic night In our satellite the moon we see sea the earth as it would appear without a protecting and life- life supporting atmosphere atmosphere-a a dry and barren waste One effect of the atmosphere on our planet is gradually to wear down and disintegrate the rocks and mountains through the action of water vapor and air This disintegration of the rocks is continually setting free gases that are to a certain extent increasing the atmosphere of the earth Moreover many stray molecules of gas exist in interplanetary space ace and are arc swept up continually by the earths earth's atmosphere in our journeys around the sun These are arc probably probably probably ably equaled in number by the molecules that escape from the earths earth's upper atmosphere so that on the whole the atmosphere is probably neither increasing nor decreasing appreciably The displays known as the northern and southern lights are electrical phenomena of ofa a nature not yet clearly understood that are associated associated associated as- as as as- with the rare gases of the earths earth's upper atmosphere They are rarely seen outside of certain certain certain tain belts in northern and southern latitudes in inthe inthe inthe the vicinity of the north and south magnetic poles of the earth where they occur in very great in- in The Illustration Illustration tion Vividly Depicts How Thin the Earths Earth's Atmosphere Really Is Note That Three Three- Quarters of the Entire Atmosphere Is Only 7 Miles Above the Earth Even at This Moderate Modera to Height It Is Impossible for Manto Man Manto to Live LiTe Unless Uness He Brings His Own Air with Him CHART ATMOSPHERE OF OF i 1 r f 4 SHOWING UN HOTS INDICATED J IUlI BK BY VARIED 4 f i 4 AND TWILIGHT J i f. f J VERY RARE UPPER ATMOSPHERE I a lI LIMIT OF UPPER STREAMERS S. S Of J 1 0 V i Z i l. l J I i Mr MILES PRA pRACTICAL rl Al OF F. F EARTHS irM ATMOSPHERE RE l j DENSITY SI OF S SURFACE A E DENSITY E. E Ij I. I H m i l I i l ii f I RETARDED b 50 s j l' l AND ML OF SURfACE 50 i i f fj i t ii ff Jr J MILES TWILIGHT l. l EFFECT N il t J A r i J. J f f f t. t r METEORS USUALLY iH SAP I a R CONSUMED I o PH RE 41 L. L J EO COMPOSITION GASES GASES- o. o 7 SUCH AS ARGON r j I TIES ALSO DUST AND T. T l. l 7 MILES J 3 7 OF ENTIRE 1 ATMOSPHERE 4 aLa J BELOW T iY THIS N UHE N it 1 dR a t 1 2 l f 1 r n LIMIT 0 f LIMIT ATMOSPHERE O R R R R E 4 n A 4 c a-c o ARGON C 01 03 Y SURFACE OJ OF THE R N Courtesy of Science ice and aad Invention The lower streamers are at altitudes of miles or less and the upper streamers reach heights of or niles The are in some way intimately associated with the sun spot cycle and never occur except when there is unusual unusual unusual un un- un- un usual activity on the sun in the form of sun spots or There is indeed sa a close dose connection between the conditions of the sun and many atmospheric ic 1 effects such as temperature rainfall cloudiness and magnetic storms and such progress is now being made in the investigation of the effect of changes in solar activity upon the atmosphere that it is expected that before long certain of the weather effects dependent on the sun spot cycle will become largely predictable in advance |