THE MOON OF SCIENCE

Taranaki Daily News, 24 November 1934, Page 13 (Supplement)

THE MOON OF SCIENCE

FROM MYTH TO FACT

(By 1

the Rev. B. Dudley,

F.R.A.S.)

The mythical moon as we have, seen in recent articles is a live world, inhabited by men, women, children, animals and birds. What a shame that science strips it of old living creatures and gives us a dead world instead! But such are the stubborn facts known to the astronomer that he cannot picture this little satellite planet as tenanted with life comparable to that known to the Earth

The moon as a satellite is unique, inasmuch as in the matter of size it is out of ratio with the satellites of other planets in the solar system. These are very much smaller than their primaries; whereas the companion of our Earth compares with it in dimensions. It is 2,160 miles in diameter, while the primary round which it revolves is about 7,900 miles. It would take fifty moons to equal the Earth in volume. There is however a great disparity between the two bodies in mass. That of the Earth is 81 times greater than the mass of the Moon. The lunar density is only six-tenths that of the Earth. The superficial area of the Moon is about equal to Europe and Asia taken together. Of this surface we are enabled to see much more than half, though only one side of the lunar globe is ever turned toward us.

The Moon is more beautiful seen from the Earth than it could be were we able to descend upon its surface and view it at close quarters. Our ordinary telescopes enable us to see it as if at a distance of 1000 miles. In the largest telescopes its apparent distance is but 60 miles from the Earth. But the view of its features thus seen is ineffective, because every defect of atmosphere is magnified as well, rendering those features blurred and indistinct.

Any object upon the lunar surface having a diameter of a mile or more could be detected in moderate sized instruments, while the larger ones would bring into view, if only blurred, objects a quarter of a mile in diameter. Were there towns and cities as. large, say, as those of New Zealand, ranging from Wellington to New Plymouth in size, our lenses. or mirrors ■ would show them. How far they could be distinguished as such would depend upon the clearness of our atmosphere and the keenness of our vision.

As, however, very many of the lunar features are large and well defined we can see a great deal, even with the naked sight. Although'it is known that the Moon is devoid of water, the dark, rougher patches have been termed seas or maria. Galileo, the first to view the moon telescopically, called them by that name, believing it to be correct. At once these parts acquired all manner of fanciful names, as, for example, the Ocean of Calms, the Sea of Serenity, the Lake of Storms, the Bay of Rainbows. With the increase of telescopic power, these great seas have become as it were completely dried up. More striking than anything else in the lunar scenery are the craters, which often jostle" against each other as it there were insufficient room for them all. They number many thousands. The larger of these strange objects are fifty, sixty, eighty, or even a hundred miles across. In depth they are seldom more than three miles; that is, from the tops of the surrounding ramparts to the central plateaux. Many mountains, rising, sheer out from the lunar surface, tower up to a mile or two above it. .The existence of these craters and craterlets and mountain formations gives the Moon its peculiar facial appearance, rendering it of a scarred or pock-mark-ed aspect. One of the noblest of its crater formations is called Tycho, another is Copernicus. The former is far south on the Moon’s surface, and is fifty or more miles across, and about 17,000 feet in depth. Copernicus, not far from the centre of the Moon’s disc, radiates streaks which extend many hundred miles from its slopes. It was once thought, almost universally, that these creaters were formed, like those of the Earth, as a result of internal upheaval. They were of volcanic origin, that is to say. The argument was based partly on observation of their general appearance and partly on analogy. But these alone are quite insufficient to settle the question. In more recent years it has come to be believed that more likely the craters were caused by bombardment from without. At some period in the moon’s history it must have been subject to such impact. During the stress of these ill times it could easily have been treated with such indignity as would leave behind the scars we see. Even now space is far from being empty, though most of the larger, fugitive masses of matter swarming about the Sun have been swept up by gravitation, leaving only the smaller “cosmic dust, which is comparatively harmless, extant. This is known to us in the form of meteors and such fine particles as become visible, in the Zodiacal Light. Most astronomers now accept the theory of meteoritic bombardment. There are also seen upon the lunar surface great clefts or rills, some of these being 90 or more miles in length. They may be in many cases only narrow openings, although some must be a mile or more wide. Their depth may sometimes be very great. Nor are there causes in operation giving rise to the accumulation of debris that would tend to fill them up, as Earth chasms are often filled up. These rills, like the central, depths of the lunar craters, are remarkable for their dense black shadows. They are quite unlike the bright streaks radiating from Copernicus and Tycho. Great mountain ranges not very ditferent from those of the Earth, are a marked feature of the Moon landscapes. The lunar Alps and Appenines, some of whose pinnacles are nearly 20,000 feet high, are a rare sight indeed. Not far from the South Pole are two mountain chains which, because the sun never sets upon their peaks, have been called “the mountains of external light.” One of these summits is 36,000 feet in height, or 7000 feet more than Mount Everest, the highest terrestrial peak knoyzn. Lacking air and water, and being marked by enormous extremes of temperature, it ought to be easy to dispose of the question as to whether or not there is life in the Moon. Such indeed is the case, if. by life we are thinking of the forms of life known to us. Yet it is possible for life in lower forms—a kind of rapidly developing and waning vegetation —to exist in this Ldt.e shining world nearby. This vegetation must spring up every lunar day and die down again every lunar night. A day on the Moon,’however, is not a 24hour stretch of time. As we know by the Moon's phases, and in other ways, it is a month long, and consists therefore of a day lasting about a fortnight and a night of similar duration. The question of life in our satellite is, however, highly problematic at present.