Part 3

Space: Measurement of 52

The International Day Line 54

Calendars, etc. 54

Curved Space 55

The Temperature of Space 55

Light in Space 55

Life in Space 56

The Causes of an Ice Age 56

Why Do Stars “Twinkle”? 56

Why Does the Moon Sometimes Appear Larger? 57

Are the Planets Inhabited? 57

A Few Definitions 58

INTRODUCTORY

Astronomy is one of the oldest of the sciences--as it is one of the most fascinating! The early Egyptians, Assyrians, Babylonians and Chaldeans were, as we know, great astronomers, and, considering that they were compelled to make their observations without the aid of telescopes, some of their conclusions are truly remarkable in their accuracy. Men must always have gazed at the stars, and wondered at their number and their beauty; yet it is only within the past three or four centuries that accurate ideas as to the nature, size and structure of our Universe have come into being. No subject is so calculated to impress upon man his own relative insignificance as astronomy--to show him that the speck of matter upon which he dwells is so small that it cannot even be seen, from a relatively short distance in space! How puny and absurdly trifling seem his bickerings and his disputes, his wars and his hates, his jealousies and his failures, when viewed from the standpoint of infinite time and infinite space; mere struggles upon an ant hill, which, a few million years from now, will be uninhabitable, while the sublime immensity of Nature will proceed as if nothing had happened!

Yes, astronomy is a fascinating and romantic study, and the following little book is an attempt to summarize, very briefly, the most important findings of modern astronomical science upon this question. I have endeavored to make the subject as simple as possible, and to avoid all terms of a technical character, unless these are fully explained. It is my hope that the reader may be enabled to gain a fairly clear and accurate idea as to the nature and constitution of our Universe by a perusal of this little book.

ASTRONOMY FOR BEGINNERS

ASTROLOGY

Those who have not studied this subject will often ask the question: “What is the difference between Astronomy and Astrology?” It is merely this: Astronomy studies the heavenly bodies, and their movements, etc., by all available scientific means; while astrology, also utilizing this material, further asserts that the particular relative positions which the sun, moon, planets and other heavenly bodies occupy at the moment of birth influence the individual born at that moment, and continue to influence him all through life. In other words, astrology is undoubtedly an exact science in so far as its astronomical data are concerned; but its further inference, as applied to the living human being, is not; it depends upon historic beliefs and traditions which have been handed-down for centuries. So far as astronomers have been enabled to ascertain, there is not the slightest scientific basis for any belief in astrology; assuredly it is a curious and interesting occult study, but it must be understood to lie within that realm, rather than in that of exact astronomical science.

THE SOLAR SYSTEM

When we speak of the “solar system,” we mean our central Sun, and the various planets which revolve around it. The planets, beginning with the one nearest the Sun, and proceeding outwards into space, are: Mercury, Venus, The Earth, Mars, Jupiter, Saturn, Uranus, Neptune. Most of these planets have in turn, circling round them, smaller bodies of satellites; the Earth has but one--the Moon. Other planets have more than one. The planets vary greatly in size, as well as in their relative distances from the Sun. The following may help the reader to form a mental picture of their relative distances and sizes:

Imagine a large open common; on it place a globe 2 feet in diameter, by way of representing the Sun; Mercury will then be represented by a mustard seed at a distance of 82 feet; Venus by a pea at a distance of 142 feet; the Earth also by a pea, at a distance of 215 feet; Mars will be a small pepper corn, at a distance of 327 feet; the Minor Planets by grains of sand at distances varying from 500 to 600 feet; then a moderate sized orange ¼ of a mile distant from the central point will represent Jupiter; a small orange ⅖ths of a mile, Saturn; a full-sized cherry, ¾ths of a mile, Uranus; and lastly a plum, at 1¼ miles, Neptune,--the most distant planet yet known,--though some astronomers suspect there may exist another planet still further off, and hope one day to find it. (On the same scale, the nearest “fixed” star would be 7,500 miles distant).

THE SUN

The Sun is the center of our solar (sun) system; it is the great giver of light and heat, without which life upon our planet would soon become extinct. It is an immense body, more than a million times the size of our earth. In fact, its radius is nearly twice the distance of the moon from the earth! The mass of the Sun is 332,000 times that of the earth. It gives 600,000 times as much light as the full moon. The energy radiated per square yard from the Sun is equivalent to 140,000 horse power. The heat radiated by the sun would melt a layer of ice 4,000 feet thick every hour, all over its surface. Various estimates of the amount of heat upon the surface have been made, but these do not agree,--figures all the way from 10,000° F. to 180,000° F. having been given. Certain it is that its internal heat is terrific, and there is every indication that this heat has been more or less constant for millions of years in the past. No purely physical theories of its heat are at all satisfactory. The ultimate nature and source of the sun’s heat are unknown--though various theories have been advanced by way of explanation. I have discussed this question at some length, however in my little book in the present series, “New Discoveries in Science,” to which the reader is referred. (“What Keeps the Sun Hot?”)

The nature and constitution of the sun have, of course, been studied intensively for many years by astronomers. The apparent surface of the sun is called the “photosphere” (light surface). It is the part that gives forth most of the light and heat. Above the photosphere lies a sheet of gas, probably from 500 to 1,000 miles thick, called the “reversing layer,” which is cooler than the photosphere. Outside the photosphere is another layer of gas, from 5,000 to 10,000 miles deep, called the “chromosphere” (cooler sphere). The outermost portion of the Sun is the “corona” (crown). It is a halo of pearly light surrounding the sun, but it cannot be seen except during a total eclipse. It is of irregular form, and gradually fades out into the blackness of space at a distance of from 1,000,000 to 3,000,000 miles. This must not be confounded with the so-called “prominences,” which are vast eruptions of flame, spurting out from the sun’s surface, and extending into space for enormous distances--perhaps half a million miles! These also travel with enormous velocity--five or six hundred miles per second. The earth would appear an insignificant speck of dust, in this vast, roaring furnace of flame!

Of late years, the question of the so-called “sun spots” has aroused a great deal of interest, partly by reason of the fact that they apparently affect electrical and magnetic conditions upon the earth. These “spots” seem to reappear at stated intervals, and about every eleven years reach their maximum intensity, (The period of the revolution of the sun on its own axis has been estimated by their study.)

Although the sun-spots were studied before the eighteenth century, it is only within the past few years that the significance of these enormous spots has become known. For long it was thought that they were merely the great volcanoes of the sun; centers of great heat, generated by the glowing, fiery gases of the sun. In 1908, however, Prof. Hale demonstrated that the sun-spots acted as attraction centers, which drew towards them the hydrogen of the solar atmosphere. “Subsequently, it was found that these spots are the seats of great cyclones, in which cool hydrogen gas is set whirling and is sucked down in the great mælstrom of the Sun, rushing into the center of the spot at the rate of 60 miles a second. Consequently the spots are the center of great solar disturbances, which are of an electromagnetic nature.” From this it was concluded (1) that the spots are cooler than the surrounding area; (2) they are centers of violent cyclones; and (3) they are magnetic fields of great intensity. The connection of sun-spots with our weather, and the relation of one to the other, have also been studied within the past few years.

MERCURY

This is the smallest of the planets in our solar system, being only about 3,000 miles in diameter. It revolves round the sun in almost exactly 88 days, at a distance of approximately 36,000,000 miles, varying between 28½ million to 43½ million miles. Owing to its smallness, it is often difficult to see this planet, and a powerful telescope must be employed to study it effectually. It is thought that Mercury possesses mountains, but it is practically devoid of atmosphere. Dark, irregular spots have been observed upon the planet, and its surface is thought, by some astronomers, to resemble that of Mars, to a great extent. The solar heat on Mercury is about seven times that on us, owing to its proximity to the Sun. Schiaparelli, and others, have contended that the period of rotation of Mercury is exactly equal to its period of revolution round the Sun. If that be true, one side of the planet is always turned to the Sun, and the other side away from it. One side of the planet would thus be intensely hot, while the other side would be icy cold. Comparatively little is known concerning this small planet, though much study has been devoted to it.