WONDERS OF THE MOON

Evening Star, Issue 22445, 16 September 1936, Page 7

WONDERS OF THE MOON

ASTRONOMICAL SOCIETY LECTURES TWO INTERESTING ADDRESSES The diameter of the moon is nearly 2,163 miles, or rather more, than a quarter. of the earth’s diameter. Its superficial are'a is rather : more than 1-14 of . the earth’s surface, " and its volume is about 1449 that of the earth. The density of .this heavenly body is to the density of the earth as 61 to 100. The . gravity at the surface of the moon is 1-6 of the gravity at the surface of the earth, so that an object suspended on a spring balance and weighing 61bs on earth would' Veigh only 11b on the moon. At its nearest point to the earth the moon • is. 221,614 miles away. . These were some of the interesting facts revealed during two. lectures delivered to members of the Astronomical Society last , night by Mr 1. D, Anderson and Mr W. H. B. Hobbs, their respective subjects being ‘ The Moon,’ and ‘Formations on- the Moon.’ At the conclusion of their addresses, both speakers were; accorded a warm vote of thanks on the motion of Dr R. Jack (chairman). EARTH’S NEAREST NEIGHBOUR. The very beginnings of .astronomy seemed to have, lain an the study of the moon’s phases, her motions,' and the phenomena she .caused,, said Mr Anderson. Important* however*, as the moon was to astronomers, it • was one of the least of .the heavenly bodies. Not only was, the. moon early, known to. be an opaque, spherical" body shining by reflected sunlight,, but it was: also known that it. .was -the nearest of the earth’s celestial-neighbours, Aristotle showed by. noting, oceultations, that the moon vygs nearer to Mars than any of the freed stars. The lecturer dealt with the infiuence.Of the moon on the life and history of the world and the different shapes it assnined when "waxing and. waning. Before the. invention of the telescope people lost themselves' in all kinds of conjectures as to ' the r nature of the strange lunar figure. It. was held to be a mysterious world, the more extraordinary in that it always presented the same face... The invention of the telescope, however, altered alt those fantastic assumptions. The first observations of Galileo revolutionised the science, for it was soon observed that it .closely resembled the earth in. its geographical features. Its surface bristled with sharp mountain peaks that were lit up in so many luminous points by the sun. Because of its motion in its orbit round the earth, which, it completed in about 27 143 days, the moon was found on each successive night to have shifted eastward along the meridian about 51min later every da fir Anderson said there was no doubt that the tides, which the moon and sun held up in the oceans of the earth, were acting as a brake upon the earth s daily rotation’ and must- m the long run, though very slowly, have the effect of lengthening the earth’s day. The lecturer dealt exhaustively with the characteristic markings •of the moon, and proceeded to enumerate its usefulness to navigators, to whom it was a perfect clock. The lecturer concluded by giving a brief description of the earth and sun as they would appear from the moon. PLANET’S INTERESTING FORMATION. Outside of the earth, the moon was the only body on which one could study details of the surface so as to form a mental picture of the scenery, Mr Hobbs told his listeners. Although the moon was considered to be the offspring of the earth, the surface conditions were utterly different from those on terra firma. The moon - had no, atmosphere, and the clear-cut features of its surface could be studied. Seen through a telescope, details such as small craters, ringed, planes, and shadows were clearly and finely defined and presented to the eye a beautiful picture of ruggedhess and smoothness. One could not but ask how the moon was formed. When it was young and in a plastic state the different formations could have come about by either volcanic action or by an attack of myriads of meteorites; Noted astronomers were at variance as .to the theory of the moon’s advent. ■ “So long as the moon can' be studied with the naked eye; it is only natural to think of it as a miniature earth with oceans and continents, said Mr Hobbs, who proceeded to enumerate the features that were similar to terrestial scenery. There were indeed plenty of mountains and hollows, the lighter parts of the surface being exceedingly rough, but there the similarity to terrestial scenery seemed to end. There was an astonishing absence of continuous mountain chains so common on earth. .The. whole scene was dominated' by a multitude of circular forms. Mr Hobbs enumerated several early astronomers who had discovered different phases of the moon’s features. He also quoted the 12 largest mountains of that planet, and remarked that three were higher than Mount Everest, There were over 50,000 formations on the . moon and 63 craters with diameters exceeding 53 miles. . Interest was lent the lecture by the screening of several lantern slides depicting certain. surfaces of : the moon.