Speaker 1: Section twenty two of Sun, Moon and Stars Astronomy for Beginners.
Speaker 1: This is a LibriVox recording. All LibriVox recordings are in
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Speaker 1: and Stars Astronomy for Beginners by Agnes Geburn, Part three,
Speaker 1: Chapter one, Many Suns, I even my hands have stretched
Speaker 1: out the heavens and all their host have I commanded
Speaker 1: Isaiah forty five twelve. Once more we have to wing
Speaker 1: our flight far far away from the busy Solar system
Speaker 1: where we live, away from whirling planets, moons, meteorites, all
Speaker 1: shining with reflected light, away from the great central Sun himself,
Speaker 1: our own particular bright star. Once more we have in
Speaker 1: imagination to cross the vast black empty space. Is it black?
Speaker 1: And is it empty? Had we sight to see things
Speaker 1: as they are separating our Sun from other suns, our
Speaker 1: star from other stars. For the Sun is a star
Speaker 1: only a star, and stars are suns, big blazing suns.
Speaker 1: One is near and the others far away. That is
Speaker 1: the main difference. We have no longer to do with
Speaker 1: bodies merely reflecting another's light, always dark on one side
Speaker 1: and bright on the other. But with burning bodies shining
Speaker 1: all around by their own light, we have no longer
Speaker 1: to picture just one single star with his surrounding worlds.
Speaker 1: But we have to fix our thoughts upon the great
Speaker 1: universe of stars or suns in countless millions. The Sun
Speaker 1: is center and ruler and king in his own system,
Speaker 1: but as a star, he is only one among many stars,
Speaker 1: some greater, some less than himself. Thought travels fast, faster
Speaker 1: than a comet, faster than light. A rushing comet would,
Speaker 1: it is believed, take eight millions of years to cross
Speaker 1: the chasm between the nearest known fixed star and us.
Speaker 1: Light flashing along at the rate of about one hundred
Speaker 1: eighty six thousand, three hundred miles. A second will perform
Speaker 1: the same journey in four years and one third, But
Speaker 1: Thought overleaps the boundary in less than four minutes. Each
Speaker 1: star that we see in the heavens is, to our
Speaker 1: eye sight, simply one point of light. The brighter stars
Speaker 1: are said to be of greater magnitude, and the fainter
Speaker 1: stars of lesser magnitude. Yet one and all, they have
Speaker 1: no apparent size. The most powerful telescope, though it can
Speaker 1: increase their brilliancy, cannot add to their size. A planet,
Speaker 1: which to the naked eye may look like a star,
Speaker 1: will under a telescope show a disc, the breadth of
Speaker 1: which can be measured or divided. But no star has
Speaker 1: any real sensible disc in the most powerful telescope yet constructed.
Speaker 1: The reason of this is the enormous distance of the
Speaker 1: stars far off as many of the planets lie, Yet
Speaker 1: the farthest of them is a member of our own
Speaker 1: household compared with the nearest star. I have already tried
Speaker 1: to make clear the fact of their vast distance. Light,
Speaker 1: which comes to us from the Sun in less than
Speaker 1: nine minutes, takes four years and four months to reach
Speaker 1: us from Alpha Centauri. From this four years and a
Speaker 1: half length of journey between Alpha Centauri and other Earth,
Speaker 1: the numbers rise rapidly to twenty years, fifty years, hundreds
Speaker 1: of years, even thousands of years. The distances of most
Speaker 1: of the stars are completely beyond our power to measure
Speaker 1: the whole orbit of our Earth. Nay, the whole wide
Speaker 1: orbit of the far off Neptune would dwindle down to
Speaker 1: one single point if seen from the greater number of
Speaker 1: the stars it used to be believed that taking the
Speaker 1: stars generally, there was probably no very marked difference in
Speaker 1: their size, their kind, their brightness. Some of course would
Speaker 1: be rather larger, and others rather smaller. Still, it was
Speaker 1: supposed that they might be roughly classed as formed much
Speaker 1: on the same scale and the same plan. But of
Speaker 1: late years this notion has been utterly given up. A
Speaker 1: very similar idea used to be held with regard to
Speaker 1: the solar system. The wonderful variety of form and richness
Speaker 1: in numbers now known to abound within its limits are
Speaker 1: discoveries of later years. And now the same variety in
Speaker 1: kind and size is found also among the stars. The
Speaker 1: more we look into the heavens, the more we see
Speaker 1: that dull, blank uniformity is not to be found there.
Speaker 1: It is the same upon earth. Man builds his little
Speaker 1: rows of box like houses side by side, each one
Speaker 1: exactly like all the rest, Or dresses his thousand soldiers
Speaker 1: in coats of the same cut and color, or repeats
Speaker 1: a neat leaf design hundreds of times on carpets or wallpapers.
Speaker 1: But God never makes two leaves or two blades of
Speaker 1: grass alike wholesale, turning out of things after one pattern
Speaker 1: is quite a human idea, not divine. We know so
Speaker 1: much about the stars as that some are at least
Speaker 1: considerably larger and some considerably smaller than others. When one
Speaker 1: star is seen to shine brightly and another beside it
Speaker 1: shines dimly, we are apt to think that the brightest
Speaker 1: must be the nearest. Yet it is often impossible for
Speaker 1: us to say how much of the difference is owing
Speaker 1: to the greater distance of one or the other, or
Speaker 1: to the greater size of one or the other, or
Speaker 1: to the greater brilliancy of one or the other. In
Speaker 1: many instances we do not know enough to be quite
Speaker 1: sure that there is a great difference not only in
Speaker 1: the distance of the stars, but in their size, their kind,
Speaker 1: their brightness. The stars have been sometimes classified into four
Speaker 1: distinct orders or degrees, partly depending on their color. The
Speaker 1: first class is that of the white suns. These are
Speaker 1: generally held to be the grandest and mightiest of all
Speaker 1: the stars. Serious belongs to the order of white suns.
Speaker 1: Secondly comes the class of golden suns. To these blazing
Speaker 1: orbs of yellow light, said to be second only to
Speaker 1: the white light stars, belongs our own sun. Thirdly, there
Speaker 1: are numbers of stars called variable stars, the light of
Speaker 1: which is constantly changing, now becoming greater, now becoming less. Fourthly,
Speaker 1: there is the class of small red suns, about which
Speaker 1: not so much is known. These four orders or divisions
Speaker 1: do not, by any means include all the stars, or
Speaker 1: even all the single stars. Roughly speaking, however, the greater
Speaker 1: number of single stars, and many also of the double stars,
Speaker 1: belong to one or another of the above classes. When
Speaker 1: we talk of the different sizes of the different stars,
Speaker 1: it should be plainly understood that we have no means
Speaker 1: of directly measuring them. A point of light showing no disk,
Speaker 1: no surface, no breadth, cannot be measured, for there is
Speaker 1: nothing to measure. In certain cases, we are not entirely
Speaker 1: without the power of judging. The distances of some of
Speaker 1: the stars from us have been found out. Knowing how
Speaker 1: far off any particular star is, astronomers are able to
Speaker 1: calculate exactly how bright our own sun would look at
Speaker 1: that same distance. If they find that our sun would
Speaker 1: shine just as the star in question shines, there is
Speaker 1: some reason for supposing that our sun and yonder star
Speaker 1: may be of the same size. If our sun would
Speaker 1: shine more brightly than the star shines, there is some
Speaker 1: reason for supposing that the star may be smaller than
Speaker 1: our sun. If our sun would shine more dimly than
Speaker 1: the star shines, there is some reason for supposing that
Speaker 1: the star may be larger than our sun. Other matters, however,
Speaker 1: have to be considered. Suppose we find a star at
Speaker 1: a certain distance shining twice as brilliantly as our own
Speaker 1: sun would shine at that same distance. Naturally, then we
Speaker 1: say that star must be much larger than our sun.
Speaker 1: The reasoning may be mistaken. We do not know the fact.
Speaker 1: What if, instead of being a much larger sun, it
Speaker 1: is only a much brighter sun. This is more than possible.
Speaker 1: Some doubts have been indeed expressed whether the surface of
Speaker 1: any star could exceed that of our sun in radiance.
Speaker 1: But we have really no reason to suppose that our
Speaker 1: son is a king of sons in brilliance, since certainly
Speaker 1: he is not so inside in speed. When we picture
Speaker 1: to ourselves the star depths the boundless reaches of heavenly space.
Speaker 1: With these countless blazing suns scattered broadcast throughout, we have
Speaker 1: not to picture a universe in repose. On the contrary,
Speaker 1: all is life, stir energy, Just as in the busy
Speaker 1: whirl of our solar system knows such thing as rest
Speaker 1: is to be found, so also it seems to be
Speaker 1: in the wide universe. Every star is in motion, fixed
Speaker 1: as we call them. They are not fixed invisible, as
Speaker 1: their movements are to our eyes through immensity of distance.
Speaker 1: Yet all are moving. Those silent, placid, twinkling specks of
Speaker 1: light are in reality huge, roaring, seething, tumultuous furnaces of
Speaker 1: fire and flame, heat and radiance. Each too is hurrying
Speaker 1: along his appointed pathway in space. Some move faster, some
Speaker 1: move more slowly. One mile per second, ten miles per second,
Speaker 1: twenty fifty hundreds of miles per second. Thus varying are
Speaker 1: their rates of speed, but rather fast or whether slowly still?
Speaker 1: Onward and ever onward they press. Some are rushing towards us,
Speaker 1: Some are rushing away from us. Some are speeding to
Speaker 1: the right, some are speeding to the left. Where are
Speaker 1: they going? Does any single star ever return to his
Speaker 1: starting point? Wherever that starting point may have been? Do
Speaker 1: they journey in vast circles or ellipses round some far
Speaker 1: distant center. What controls them all? Is it the mighty
Speaker 1: power of some such center, Or does each star, by
Speaker 1: his faint and distant attraction, help to contryro all his
Speaker 1: brother stars, to guide them on their appointed path, to
Speaker 1: preserve the delicate balance of a universe. How little we
Speaker 1: know about the matter, Only so much we can tell
Speaker 1: that the controlling and restraining hand of God is over
Speaker 1: the whole, Whether by the attraction of one great center
Speaker 1: or by the united influences of a thousand fainter attractions.
Speaker 1: He steers each radiant sun upon its heavenly path, upholding
Speaker 1: all things by the word of His power. There is
Speaker 1: no blundering, no confusion, no entanglement. All is perfect order,
Speaker 1: calm arrangement, restrained energy. End of Section twenty two.