The Music of the Spheres/Chapter 11

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4417930The Music of the Spheres — Chapter XI.Florence Armstrong Grondal



Stars are suns which lie at such vast distances that they seem no more than twinkling points of light. Through the aid of the spectroscope we have learned a great deal about these stars but so distant do they lie that no telescope on earth can bring them close enough for us to see the outline of a face.

There is one star, however, that lies so near that when it is in the sky its light blots out that of all the other stars. This sun, which classic poets call our "day star," lies only 93,000,000 miles away; the next nearest star is over 200,000 times as far. This distance of 93,000,000 miles is close enough to enable us to examine the face of such a star as ours with comparative ease, indeed, it is close enough to enable us to feel the warmth of the fierce fires which rage upon its surface.

It is not at all a difficult matter to realize the distance from our earth to the sun. A train traveling 60 miles an hour would reach the sun in 176 years; an airplane flying at the rate of 200 miles an hour would reach it in 50 years. Thus the distance seems to shrink as we adjust our rate of speed. A ray of light crosses the same space in about 8 minutes.

The existence of all life upon the earth is absolutely dependent upon the sun.

"It is perceived that the sun of the world, with all its essence, which is heat and light, flows into every tree, and every shrub and flower, and into every stone, mean as well as precious."

Equally dependent are the seven other planets which, with the earth, whirl in elliptical orbits about this source of heat and light.

"The Sun the seasons of the year supplies
And bids the evening and the morning rise;
Commands the planets with superior force,
And keeps each wandering light to his appointed course."
Lucan's Pharsalia.

The planets are sometimes called the "family" of the sun, although his family also includes the retinue of each planet, which in the case of six of them at least, consists of from one to ten moons. Our sun is no different than thousands of other stars in the sky; is it likely that our star alone of all the countless millions which shine in our universe, should be the only one to possess this additional charm of maturity? One looks far out in the darkness to the hosts of radiant stars—then wonders—how many stars have flocks of planets—how many travel alone?

The Surface of the Sun

Compared to a point of starlight, the disk of our "day star" looks most exceedingly huge, and this at a distance of 93,000,000 miles. One is therefore not quite so surprised to learn that this great sunball, which rests like the hub of a wheel in the center of the solar system, has a diameter of 886,000 miles. The 8000 miles which measures across the earth seems quite inconspicuous when compared with such a diameter as this.

Completely covering the sun's surface is a mass of intensely hot crimson gases. These gases are like a turbulent upper atmosphere with a depth of 5000 to 10,000 miles. Raging and seething in long tongues of flame, they swirl up for thousands of miles above the surface, or are thrown far above it in titanic explosions. Formerly, these burning gases could only be seen at the time of total eclipse when the black disc of the moon passed in front of the glaring face of the sun leaving only the red flames licking out beyond the dark edge. The invention of the spectroheliograph now makes it possible to photograph these projections when the sun is shining. One should never try to see them by looking at the sun unless the glare is shut off either by the moon or by artificial means, for the sun is so unbearably brilliant that the eyesight of an observer would soon be ruined.

This colorful gas which covers the surface of the sun, is called the chromosphere or color-sphere
Huge flames ejected from the surface of the sun, photographed at Yerkes Observatory
with the Rumford spectroheliograph attached to the 40-inch refractor.
on account of the vivid color which it acquires from the hydrogen and calcium of which it is largely composed. The colossal flames which rise above its surface are called prominences. Some of the prominences shoot up with a velocity ranging from 300 to 600 miles a second, sometimes to a height of 200,000 miles, and even higher. The largest so far recorded extended upward for 500,000 miles. Others extend horizontally for a distance of over 300,000 miles, racing forward at the rate of a thousand miles a minute, although sometimes they remain in an unchanged position above the surface of the sun for days at a time. These flames seem tremendous compared to our terrestrial standards, but they would not seem so large on the globe of the sun which is 3,000,000 miles in circumference.
Photographed with the aid of the spectroheliograph at the Mount Wilson Observatory.
It seems strange to think that the "tranquil stars" must also be seething in such wild commotion,—blazing orbs torn by terrific tornadoes of fire. It is fortunate that we cannot hear the terrible roar as well as see the light of their conflagrations. Since sound waves do not travel through space like the waves of light and heat, the tumult on even our nearest star could never reach us; yet sound is such a laggard traveler compared with fleet-winged light, that light could cover the distance of 93,000,000 miles in less than 8 minutes while sound would require over 14 years to travel over the same space. Thus, even if we could hear the voices of these explosions, they would never coincide with the scenes enacted.

The bright yellow surface of the sun which every one sees, is called the photosphere or light-sphere. If strongly magnified through a telescope, this surface is seen to have a decided "mottled" appearance, like a layer of little clouds with dark spaces between, spread over the whole face of the sun. These are now known to be masses of calcium gas.

Practically all that is known of the physical constitution of the sun has been discovered through the study of the fine, dark lines in the solar spectrum. Through the aid of the spectroscope, many terrestrial elements have been discovered, among these being calcium, sodium, magnesium, potassium, aluminum, silver, iron, nickel, copper, zinc, tin, lead, hydrogen, oxygen and carbon. All these elements are either in the form of permanent gases or metallic vapors.

The photosphere or light-sphere lies below the chromosphere or color-sphere. Beyond the crimson color-sphere lies another envelope of very delicate light called the corona. This may only be seen at the time of total eclipse. It was once thought to belong to the moon but it is now known that the moon has very little atmosphere. Besides, the moon's black disk may be seen floating across this beautiful halo of light.

The corona has been described by those who have seen it, as having a "soft, pearly radiance" "tinged with green"; its form is quite irregular and varies at different times, extending from 1,000,000 to 3,000,000 and sometimes even 9,000,000 miles beyond the surface of the sun. In the eclipse of 1879 the streamers were quite extensive in the equatorial plane of the sun where they united in a formation like the petals of a narcissus while at the solar poles they were shorter and extended in well-defined rays. Yet no matter what its form, it is a magnificent background during the sun's eclipse for the narrow rim of deep crimson projects beyond the inky edges of the moon.

The corona seems to be caused by electrical discharges in a medium of fine dust and rarefied gases, chiefly coronium and proto-fluorine. Various electrical phenomena take place in the strong magnetic fields of the sun as a whole and in the sun-spots, and the changing fields of magnetic force cause the changing appearance of the corona.

The sun-spots, however, are of the greatest interest to amateurs for these may often be seen with very little optical aid. These dark, movable spots were first noted by Galileo, although the idea that the sun could have spots upon its surface was ridiculed by the scholars of the medieval schools who argued in the fervid language of scholastic philosophy and medieval dogmatism, that the sun was a sphere of pure fire undefiled by any spots.

Sun-spots are, as a rule, thousands of miles across and usually appear in groups which cover an immense area on the surface of the sun, but, since the sun lies 93,000,000 miles away, a spot large enough to contain the earth would appear to us about the size of a pinhead on a pincushion. Right here one should be warned again not to attempt to look at the sun without adequate protection (such as smoked glasses) for the eyes. A photograph taken through a large telescope is the most satisfactory. Although these dark blotches—which are only comparatively dark—were called "spots" and were later drawn as saucer-like depressions, modern research and increased power in the telescopes has revealed them as gigantic solar tornadoes. These tornadoes usually last from a few days to several months, and are especially numerous in cycles of 11 years. During sun-spot activity eruptive prominences rise to heights of many thousands of miles and streams of electrons are shot forth with such force that they may possibly even penetrate deeply into our own atmosphere causing disturbances such as magnetic storms and auroras.
The earth is so small compared with the huge bulk of the sun that it would be lost in one
of these "spots." Photograph by the Mount Wilson Observatory.
If a total solar eclipse occurs at a time when these great magnetic storms are raging in particular fury on the sun's surface, the corona always appears brighter and more intricate than when the sun is peaceful.

Sun-spots were very numerous in 1915 and 1916. The next spot maximum will occur about 1926, then in 1937 and so on. For three years or four years they appear with great frequency, then declining to a minimum for three or four years, rise to a maximum again; thus the period from maximum to maximum is about 11 years.

Through watching these black spots disappear around one edge of the sun and then reappear after an interval of time on the other side, Galileo discovered that the sun turned completely around on its axis in 25 days.
Compare with photograph on page 214, also made on same day by the Mount Wilson Observatory.
Further study disclosed the still stranger fact that the sun does not turn around in a solid body. Areas near the equator were found to complete a revolution in 25 days, but they were seen to forge ahead of those regions in higher latitudes; 45 degrees north and south latitude, the rotation period is 27½ days; 60 degrees north and south latitude, the period is 31.2 days, and in 80 degrees north and south latitude, the period is 35.3 days. This alone can be regarded as proof that the sun's apparent surface is not solid but is either in a liquid or gaseous state.

An Eclipse of the Sun

A total eclipse of the sun is caused by the moon passing between the earth and the sun, and since the moon is apparently the same size as the sun in the heavens, it hides the bright face of this luminary from our view; but the long shadow which trails behind the moon must touch the earth. The shadow moves along a narrow strip as the earth revolves and only those who are in this shadow can see the sun totally eclipsed.

If the shadow of the moon does not quite touch the earth, the moon's disk does not quite cover the sun. Then the dark body of the moon is seen surrounded by a ring of light. This is called an annular eclipse.

In a partial eclipse, the sun's disk suddenly becomes indented on one side, the indentation slowly increasing for some time, and then diminishing until it disappears altogether.

Total solar eclipses are extremely infrequent in any one place because of the smallness of the cone of the moon's shadow. This shadow draws a black streak across the earth, which, under favorable circumstances, may have a breadth of a little more than 160 miles and a length of 10,000 to 12,000 miles. The width of the shadow depends upon the nearness of the moon for if its shadow just touches the earth, the streak will have no sensible width. A partial solar eclipse is visible 2,100 miles or more on either side of the region where the eclipse is total. Since the shadow of the moon passes across the earth at the furious rate of 1300 miles an hour, a total eclipse of the sun lasts for only a few minutes,—and for this length of time, short as it is, some thanks is due to the fact that the earth, in revolving upon its axis, carries the observer and the ground upon which he stands along the same direction in which the shadow is moving.
(The two words at the point of the shadow's contact with the Earth are "Catalina" and "San Diego.") Drawing by Dr. Mars F. Baumgardt, Curator of Clark Observatory, Los Angeles, Calif.
Total eclipses are of extremely rare occurrence and only happen about once in every three hundred years for any selected spot on the earth's surface.

An interesting description of a total eclipse may be found in Flammarion's "Astronomy for Amateurs":

The luminous disk of the sun is gradually corroded. Another disk, as black as ink, creeps in front of it and little by little invades it entirely. The atmosphere takes on a wan, sepulchral hue; astonished nature is hushed in profound silence; an immense veil of sadness spreads over the world. Night comes on suddenly, and the stars shine out in the Heavens. It seems as though by some mysterious cataclysm the Sun had disappeared forever."

Professor Moulton in his "Astronomy" gives another splendid description:

"It always occurs precisely at new moon, and consequently the moon is invisible until it begins to obscure the sun. Steadily the moon moves over the sun's disk; and, as the instant of totality draws near, the light rapidly fails, animals become restless and everything takes on a weird appearance. Suddenly a shadow rushes across the surface of the earth at the rate of more than 1300 miles an hour, the sun is covered, the stars flash out, around the apparent edge of the moon are rose-colored prominences of vaporous material forced up from the sun's surface to a height of perhaps 200,000 miles, and all around the sun extending out as far as half its diameter are streamers of pearly light which constitutes the sun's corona. After seven minutes at the very most, the western edge of the sun is uncovered and daylight suddenly appears."

In "New Astronomy," Langley tells of the sensations of an observer as the moon's shadow passes furiously on its way:

"The bright cloud I saw distinctly put out like a candle. The rapidity of the shadow, and the intensity produced a feeling that something material was sweeping over the earth at a speed perfectly frightful. I involuntarily listened for the rushing noise of a mighty wind."

On June 8th, 1918, September 10, 1923, and on January 24th, 1925, many people in the United States were privileged to view the wonderful spectacle of a total eclipse. Scientists came from all over the world to witness the solar eclipse of 1923, for not only was it visible from an attractive corner of our country at a pleasant time of the year, but the sun was at a convenient altitude for observation. Many photographs were taken of the great flaming corona, some even from airplanes.

Although people now travel halfway across the earth in order to be able to witness an eclipse, in olden days such an occasion was marked by the greatest terror.
Photographed during the eclipse of June 8, 1918, at Green River, Wyoming, by the Mount Wilson Observatory Expedition.
To the ancients they were without the order of nature, and in Rome, at one time, it was blasphemy, and punishable by law, to talk publicly of their being due to natural causes.

The Chaldeans believed the sun and moon to be black on the hidden side, and upon the displeasure of the Gods, the darkened
Photographed by Edith Carlson at Palo Alto, California, September 10, 1923.
side was turned to the earth thus causing an eclipse. Many people among the European nations covered their wells and fountains for fear that the water would become contaminated by the poisonous, mists which arose during an eclipse. The notion was probably due to the fact that the drop in temperature is often accompanied by a fall of dew.

The Peruvians thrashed dogs during an eclipse so that their howling would keep evil spirits away, and for the same reason, the Romans beat their pots and pans, lifted up torches and fire-brands into the air. The people of the Northern nations also created a great din, for they imagined that the sun was pursued by fierce wolves (Skoll and Hati), who tried to swallow their brilliant prey so that the world would return to its primeval darkness.

Crooke, in "Popular Religion and Folk-Lore," says that

"A high-caste Hindu will eat no food that has remained in the house during an eclipse, and all earthen vessels which are in the house at the time, must be broken. During an eclipse all household business is suspended, and eating and drinking is prohibited, even sleep at such times is forbidden, for it is then that the demons and devils are most active. The most effectual way of scaring the demon Rahu and releasing the afflicted planets is to bathe in some sacred stream and for protection, a Brahman should stand in the water beside the worshipper and recite the Gayatri."

It is said that at such times the rivers are covered with human heads.

Some barbarian tribes imagined that when the sun or moon began to lose its light, the orb was sickening under the arts of a wicked magician and they danced and screamed and beat their tomtoms in a wild frenzy so that the wicked one might become afraid and steal away. The well-known idea of the Chinese, however, is the most interesting of all, for there are records showing that for several thousand years these people believed that an eclipse was caused by the attempt on the part of a huge black dragon to seize the burning ball and swallow it. The dread of such a catastrophe so preyed upon the minds of the populace that it is reported in the "Tshu-King," one of the oldest chronicles in existence, that the ancient astronomers Ho and Hi had their heads laid before their feet for failing to predict an eclipse of the sun. Plenty of time to get out drums and kettles and to make the deafening noise which had always caused the monster to drop the sun was always given after this little incident. Douglas, in "History of China," relates that at this time, the intervention of every official in the country is called upon to save the sun from being destroyed.

"Some months before the expected eclipse the board of astronomers notifies the exact date of its appearance to the officials of the board of rites, who in their turn announce its appearance to the viceroys and governors of the provinces. They transmit the message to all their subordinates, so that, when the time arrives, an army of mandarins stand prepared to avert disaster. Their procedure is simple and as neither the sun nor the moon have ever been devoured, it is regarded as efficacious. At the appointed time the mandarins assemble at the yamen of the senior official, and arrange themselves before an altar set up in the courtyard, on which incense is burning. At a given signal, they fall down on their knees and perform Ko-t-ow, after which the attendants beat drums and gongs to frighten away the oppressive monster, while the priests move in a procession round the altar chanting prayers and formulas. To assist the mandarins in their patriotic efforts, the people mount to the roofs of their houses, and add to the din which issues from the yamen by beating everything capable of emitting resounding noises."

The Grecians, however, ascribing all things to the gods, thought that the phenomenon was due to Jupiter, who, sometimes wishing to keep his business on earth secret from the other immortals on Mount Olympus, kept them from seeing him by hanging a little covering over the sun.

"The Olympian Father hangs a noon-day night
O'er the sun's disk and veils its glittering light,
Fear falls on man. Hence miracles, before
Incredible, are counted miracles no more."
Archilochus. (Trans. by Sir Chas. Abraham Elton.)