What's On the Moon? 



Look through the telescope with us and see the great 

 mountains, the vast dead craters and arid wastes of slag 



By Scriven Bolton, F. R. A. S. 



Illustrations specially prepared for Popular Science Monthly by the author 



SUCH is the power of our largest tele- 

 scopes that a creature as large as an 

 elephant might be detected on the 

 moon. Hence we are more familiar with 

 the lunar surface than with Central Africa. 

 Since there is no appreciable air on the 

 moon, our view is always clear and un- 

 obstructed. 



Why has the moon no atmosphere? 

 Simply because the force of gravity is so 

 small. The weight of an object on any 

 planet depends upon the mass of that 

 planet. On Jupiter, the largest of all 

 planets, you would have difficulty in lifting 

 your arm from your side. On the Sun you 

 would probably need a steam crane to 

 help you move about. On Mars you could 

 jump over a small house. Small planets, 

 including the earth, are gradually losing 

 their atmosphere. The smaller they are 

 the more rapid is that rate of loss. And 

 since the moon is very small, it lost its 

 atmosphere long ago. Thus is to be ex- 

 plained the fact that the earth is still 

 wrapped in air although the moon, child 

 of the earth though it is, is airless. Because 

 of this entire absence of air astronomers 

 consider it improbable that there is any 

 lunar life. Perhaps there . may be rem- 

 nants of vegetation within certain low- 

 lying craters and in the deepest valleys 

 and chasms where a few shreds of atmos- 

 phere may still pervade. But nothing of 

 the kind has as yet been detected, and 

 as we gaze in bewilderment into every 

 crack and crevice of the surface we rightly 

 conclude that the moon is a truly barren 

 world. 



On Top of a Lunar Mountain 



Although we cannot fully realize existence 

 on the moon, it is nevertheless the inevitable 

 experience of the astronomer when tele- 

 scopically raking the lunar surface with 

 what might be justifiably termed an eye of 

 the earth to identify himself to such an 

 extent with the scrutinized scene that he 

 ofttimes unconsciously thinks himself a 

 lunar inhabitant. It really requires but 

 little imagination to suppose oneself actually 

 planted among the lunar craters and 



mountains, viewing in awe the wonderful 

 landscape. 



Now let us endeavor to realize, by the 

 help of the accompanying illustrations, that 

 we have taken our stand upon one of the 

 mountain peaks such as we see in these 

 pictures, and by commanding an extended 

 view of the surroundings we duly note the 

 strange lunar conditions produced upon the 

 landscape. 



Dawn Is as Harsh as Midday 



The lunar day is thirteen times longer 

 than ours. Dawn, in an earthly sense, is 

 unknown, for there is no atmosphere to 

 reflect the solar beams while the sun is yet 

 below the horizon. The terribly harsh 

 solar beams suddenly appear on the black 

 horizon, dazzlingly illuminating the moun- 

 tain crests, while the valleys are still in utter 

 darkness. Because there is no atmosphere, 

 blending of the night into day at sunrise is 

 unknown, and all the gorgeous tints which 

 attend a terrestrial sunrise are on the moon 

 quite absent. On earth we are accustomed 

 to see the sun's light softened by an air 

 screen. The fierce splendor of our luminary 

 on the moon, however, is rendered more 

 obvious by the blackness of the sky, owing 

 to the absence of air. Even in broad sun- 

 shine the sky is as dark as our darkest star- 

 light nights, with the stars and planets 

 shining more brightly than it is possible to 

 see them here. The appendages to the 

 sun, such as the Zodiacal Light, the Corona, 

 and the red protuberances, appear in 

 glorious perfection. 



What a magnificent object is the earth, 

 thirteen times larger than the moon 

 appears to us, and practically stationary in 

 the heavens! It exhibits phases precisely 

 as does our moon, the interval between each 

 full "earth" being about twenty-nine days. 

 The sublime and periodical spectacles of a 

 total solar eclipse and an eclipse of the 

 "earth" are attended by circumstances far 

 more imposing than their earthly counter- 

 parts. The spectator sees the earth-globe 

 rotating on its axis, the continents, oceans, 

 and polar snow caps being well displayed. 

 Portions of the surface appear inter- 



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