[Illustration: HIPPARCHUS IN THE OBSERVATORY OF ALEXANDRIA.]
THE STORY
OF THE
SUN, MOON, AND STARS
BY
AGNES GIBERNE
AUTHOR OF “THE STARRY SKIES,” “THE WORLD’S FOUNDATIONS,”
“RADIANT SUNS,” ETC.
[Illustration]
WITH COPIOUS ADDITIONS
Fully Illustrated
CINCINNATI
NATIONAL BOOK COMPANY
COPYRIGHT, 1898,
BY J. T. JONES.
INTRODUCTION.
BY CHARLES PRITCHARD, M. A., F. R. S.,
PROFESSOR OF ASTRONOMY IN THE UNIVERSITY OF OXFORD.
The pages of this volume on a great subject were submitted to my
criticism while passing through the press, with a request from a friend
that I would make any suggestions which might occur to me for its
improvement. Naturally, such a request was entertained, in the first
instance, with hesitation and misgiving. But after a rapid perusal
of the first sheet, I found my interest awakened, and then gradually
secured; for the book seemed to me to possess certain features of
no ordinary character, and, in my judgment, held out the promise of
supplying an undoubted want, thus enabling me to answer a question
which I have been often asked, and which had as often puzzled me,
to the effect, “Can you tell me of any book on astronomy suited to
beginners?” I think just such a book is here presented to the reader;
for the tale of the stellar universe is therein told with great
simplicity, and perhaps with sufficient completeness, in an earnest and
pleasant style, equally free, I think, from inaccuracy or unpardonable
exaggeration. We have here the outlines of elementary astronomy,
not merely detailed without mathematics, but to a very great extent
expressed in untechnical language. Success in such an attempt I regard
as a considerable feat, and one of much practical utility.
For the science of astronomy is essentially a science of great
magnitude and great difficulty. From the time of Hipparchus, some
century and a half before the Christian era, down to the present
day, the cultivation of astronomy has severely taxed the minds of a
succession of men endowed with the rarest genius. The facts and the
truths of the science thus secured have been of very slow accretion;
but like all other truths, when once secured and thoroughly understood,
they are found to admit of very simple verbal expression, and to lie
well within the general comprehension, and, I may safely add, within
the sympathies of all educated men and women.
Thus the great astronomers, the original discoverers of the last
twenty centuries, have labored, each in his separate field of the
vast universe of nature, and other men, endowed with other gifts,
have entered on their labors, and by systematizing, correlating, and
simplifying the expression of their results, have brought the whole
within the grasp of cultivated men engaged in other branches of the
varied pursuits of our complicated life. It is in this sort of order
that the amelioration and civilization of mankind have proceeded, and
at the present moment are, I hope and believe, rapidly proceeding.
It was, I suspect, under this point of view, though half unconsciously
so, that my attention was arrested by the book now presented to the
reader; for we have here many of the chief results of the laborious
researches of such men as Ptolemy, Kepler, Newton, Herschel,
Fraunhofer, Janssen, Lockyer, Schiaparelli, and others--no matter
where accumulated or by whom recorded--filtered through the mind of
a thoughtful and cultured lady, and here presented to other minds in
the very forms wherein they have been assimilated and pictured in her
own. And these forms and pictures are true. It is in this way that the
intellectual “protoplasm” of the human mind is fostered and practically
disseminated.
And, then, there is still another point of view from which this general
dissemination of great truths in a simple style assumes an aspect of
practical importance. I allude to the influences of this process on the
imaginative or poetic side of our complex nature.
Wordsworth, in one of his prefaces, has stated so clearly the truth
on this subject that I can not do better than give his words. “If the
time should ever come,” he says, “when what is now science becomes
familiarized to men, then the remotest discoveries of the chemist, the
botanist, the mineralogist, will be as proper objects of the poet’s
art as any upon which it can be employed. He will be ready to follow
the steps of the man of science; he will be at his side, carrying
sensation into the midst of the objects of science itself. The poet
will lend his divine spirit to aid the transfiguration, and will
welcome the being thus produced as a dear and genuine inmate of the
household of man.”
It is for reasons such as here stated that I heartily commend this
book to the attention of those who take an interest in the advancement
of the intellectual progress and culture of society. The story of the
Kosmos is told by the authoress in her own language and after her own
method. I believe, as I have said, the story is correct.
OXFORD UNIVERSITY.
CONTENTS.
CHAPTER. PAGE.
I. THE EARTH ONE OF A FAMILY, 13
II. THE HEAD OF OUR FAMILY, 24
III. WHAT BINDS THE FAMILY TOGETHER, 34
IV. THE LEADING MEMBERS OF OUR FAMILY.--FIRST
GROUP, 46
V. THE LEADING MEMBERS OF OUR FAMILY.--SECOND
GROUP, 55
VI. THE MOON, 62
VII. VISITORS, 73
VIII. LITTLE SERVANTS, 83
IX. NEIGHBORING FAMILIES, 95
X. OUR NEIGHBORS’ MOVEMENTS, 106
XI. MORE ABOUT THE SOLAR SYSTEM, 122
XII. MORE ABOUT THE SUN, 133
XIII. YET MORE ABOUT THE SUN, 148
XIV. MORE ABOUT THE MOON, 157
XV. YET MORE ABOUT THE MOON, 164
XVI. MERCURY, VENUS, AND MARS, 180
XVII. JUPITER, 199
XVIII. SATURN, 214
XIX. URANUS AND NEPTUNE, 225
XX. COMETS AND METEORITES, 240
XXI. MORE ABOUT COMETS AND METEORITES, 246
XXII. MANY SUNS, 267
XXIII. SOME PARTICULAR SUNS, 278
XXIV. DIFFERENT KINDS OF SUNS, 291
XXV. GROUPS AND CLUSTERS OF SUNS, 304
XXVI. THE PROBLEM OF SUN AND STAR DISTANCES, 310
XXVII. MEASUREMENT OF STAR DISTANCES, 320
XXVIII. THE MILKY WAY, 329
XXIX. A WHIRLING UNIVERSE, 337
XXX. READING THE LIGHT, 344
XXXI. STELLAR PHOTOGRAPHY, 355
XXXII. THE DAWN OF ASTRONOMY, 363
XXXIII. MODERN ASTRONOMY, 375
XXXIV. SIR ISAAC NEWTON, 382
XXXV. LATER ASTRONOMY, 393
LIST OF ILLUSTRATIONS.
PAGE.
Hipparchus in the Observatory at Alexandria _Frontispiece._
The Solar System 15
The Pleiades 19
Sun-spots 29
Phases of Mercury before Inferior Conjunction--Evening Star 50
Appearance of the Full Moon 63
One Form of Lunar Crater 69
The Earth as Seen from the Moon 71
Passage of the Earth and the Moon through the Tail of a Comet 76
Passage of the Comet of 1843 Close to the Sun 79
Meteor Emerging from Behind a Cloud 84
The Great Shower of Shooting-stars, November 27, 1872 90
Constellation of the Great Bear 108
The Great Bear 50,000 Years Ago 109
The Great Bear 50,000 Years Hence 109
Constellation of Orion as it Appears Now 110
Constellation of Orion 50,000 Years Hence 111
Position of Planets Inferior to Jupiter--Showing the Zone of the
Asteroids 123
Comparative Size of the Planetary Worlds 130
A Typical Sun-spot 135
A Solar Eruption 138
Sun-flames, May 3, 1892 143
Solar Corona and Prominence 152
Comparative Size of the Earth and Sun 155
The Moon--an Expired Planet 159
The Lunar Crater Copernicus 170
Lunar Eruption--Brisk Action 172
Lunar Eruption--Feeble Action 173
Nicolaus Copernicus 176
Phases of Venus 186
Mars and the Path of its Satellites 191
General Aspect of Jupiter--Satellite and its Shadow 200
Satellites of Jupiter Compared with the Earth and Moon 206
The System of Jupiter 208
Orbits of Nine Comets Captured by Jupiter 213
Saturn and the Earth--Comparative Size 215
Ideal View of Saturn’s Rings and Satellites from the Planet 222
Great Astronomers of Earlier Times 227
The Great Comet of 1811 247
Donati’s Comet, 1858 249
Great Comet of 1744 254
The First Comet of 1888--June 4 255
Great Comet of 1680 260
Great Comet of 1769 261
Baron Alexander Von Humboldt 264
A Telescopic Field in the Milky Way 270
Cygnus, Constellation of 279
Stars whose Distances are Best Known 281
Lyra, Constellation of 297
Constellations in the Northern Hemisphere 300
A Cluster of Stars in Centaurus 305
The Great Nebula in Andromeda, Compared with Size of the Solar
System 307
A Cluster of Stars in Perseus 332
Hercules, Constellation of 338
The Great Bear, Constellation of 341
The Prism and Spectrum 344
The Spectroscope 345
Spectra, Showing the Dark Lines 347
Great Astronomers of Later Times 377
Sir Isaac Newton 386
Eye-piece of Lick Telescope 407
Lick Observatory 409
Professor E. E. Barnard 410
THE STORY
OF THE
SUN, MOON, AND STARS.
CHAPTER I.
THE EARTH ONE OF A FAMILY.
What is this earth of ours?
Something very great--and yet something very little. Something very
great, compared with the things upon the earth; something very little,
compared with the things outside the earth.
And as our journeyings together are for a while to be away from earth,
we shall find ourselves obliged to count her as something quite small
in the great universe, where so many larger and mightier things are
to be found,--if indeed they are mightier. Not that we have to say
good-bye altogether to our old home. We must linger about her for a
while before starting, and afterwards it will be often needful to come
back, with speed swifter than the flight of light, that we may compare
notes on the sizes and conditions of other places visited by us.
But first of all: what _is_ this earth of ours?
It was rather a pleasant notion which men held in olden days, that
we--that great and important “We” which loves to perch itself upon
a height--stood firm and fixed at the very center of everything. The
earth was supposed to be a vast flat plain, reaching nobody could tell
how far. The sun rose and set for us alone; and the thousands of stars
twinkled in the sky at night for nobody’s good except ours; and the
blue sky overhead was a crystal covering for the men of our earth,
and nothing more. In fact, people seem to have counted themselves not
merely to have had a kind of kingship over the lower animals of our
earth, but to have been kings over the whole universe. Sun, stars, and
sky, as well as earth, were made for man, and for man only.
This was the common belief, though even in those olden days there were
_some_ who knew better. But the world in general knows better now.
Earth the center of the universe! Why, she is not that of even the
particular family in the heavens to which she belongs. For we do not
stand alone. The earth is one of a family of worlds, and that family is
called THE SOLAR SYSTEM. And so far is our earth from being the head of
the family, that she is not even one of the more important members. She
is merely one of the little sisters, as it were.
Men not only believed the earth, in past days, to be at the center
of the universe; but also they believed her to remain there without
change. Sun, moon, stars, planets, sky, might move; but never the
earth. The solid ground beneath their feet, _that_ at least was firm.
Every day the sun rose and set, and every night the stars, in like
manner, rose and set. But this was easily explained. We on our great
earth stood firm and still, while sun, moon, stars, went circling
round us once in every twenty-four hours, just for our sole and
particular convenience. What an important personage man must have felt
himself then in God’s great universe! Once again, we know better now!
[Illustration: THE SOLAR SYSTEM.]
For it is the earth that moves, and not the sun; it is the earth that
moves, and not the stars. The daily movements of sun and stars, rising
in the east, traveling over the sky, and setting in the west, are
no more real movements on their part than, when we travel in a rail
way-train, the seeming rush of hedges, telegraph posts, houses, and
fields is real. They are fixed and we are moving; yet the movement
appears to us to be not ours but theirs.
Still more strongly would this appear to be the case if there were no
noise, no shaking, no jarring and trembling, to make us feel that we
are not at rest. Sometimes when a train begins to move gently out of
a station, from among other trains, it is at the first moment quite
impossible to say whether the movement belongs to the train in which we
are seated or to a neighboring train. And in the motions of our earth
there is no noise, no shaking, no jarring--all are rapid, silent, and
even.
If you were rising through the air in a balloon, you would at first
only know your own movement by seeing the earth seem to drop away from
beneath you. And just so we can only know the earth’s movements by
seeing how worlds around us _seem_ to move in consequence.
When I speak of the Universe, I mean the whole of God’s mighty creation
as far as the stars reach. Sometimes the word is used in this sense,
and sometimes it is used only for a particular part of creation nearer
to us than other parts. At present, however, we will put aside all
thought of the second narrower meaning.
The wisest astronomer living can not tell us how far the stars reach.
We know now that there is no firm crystal covering over our heads,
dotted with bright points here and there; but only the wide open sky
or heaven, containing millions of stars, some nearer, some farther,
some bright enough to be seen by us all, some only visible through a
telescope.
People talk often of the stars being “set in space;” and the meaning of
“space” is simply “room.” Where you are must be space, or you could not
be there. But it is when we get away from earth, and travel in thought
through the wide fields of space, where God has placed his stars, that
we begin to feel how vast it is, and what specks we are ourselves--nay,
what a speck our very earth is, in this great and boundless creation.
For there is no getting to the borders of space. As one telescope after
another is made, each one stronger in power and able to reach farther
than the last, still more and more stars are seen, and yet more and
more behind and beyond, in countless millions.
It is the same all round the earth. The old notion about our world
being a flat plain has been long since given up. We know her now to be
a round globe, not fixed, but floating like the stars in space.
When you look _up_ into the sky, you are looking exactly in the
opposite direction from where you would be looking _up_ if you were
in Australia. For Australia’s “up” is our “down,” and our “down” is
Australia’s “up.” Or, to put it more truly, “up” is always in the
direction straight away from this earth, on whatever part of it you may
be standing; and “down” is always towards the center of the earth.
All round the globe, in north, south, east, west, whether you are in
Europe, Asia, Africa, or America, though you will see different stars
in certain different quarters of the earth, still overhead you will
find shining countless points of light.
And now, what are these stars? This is a matter on which people are
often confused, and on which it is well to be quite clear before going
one step farther.
Some of the stars you have most likely often noticed. The seven chief
stars of the Great Bear are known to a large number of people; and
there are few who have not admired the splendid constellation of Orion.
Perhaps you also know the W-shape of Cassiopeia, and the brilliant
shining of Sirius, and the soft glimmer of the Pleiades.
The different constellations or groups of principal stars have been
watched by men for long ages past. They are called the fixed stars, for
they do not change. How many thousands of years ago they were first
arranged by men into these groups, and who first gave them their names,
we can not tell.
True, night by night, through century after century, they rise, and
cross the sky, and set. But those are only seeming movements. Precisely
as the turning round of the earth upon her axis, once in every
twenty-four hours, makes the sun appear to rise and cross the sky and
set, in the day-time; so also the same turning of the earth makes the
stars appear to do the same in the night-time.
There is another seeming movement among the stars, which is only in
seeming. Some come into view in summer which can not be seen in
winter; and some come into view in winter which can not be seen in
summer. For the sun, moving on his pathway through the sky, hides those
stars which shine with him in the day-time. The zodiac is an imaginary
belt in the heavens, sixteen or eighteen degrees wide, containing the
twelve constellations through which the sun passes. And as he passes
from point to point of his pathway, he constantly conceals from us
fresh groups of stars by day, and allows fresh groups to appear by
night. Speaking generally, however, the stars remain the same year
after year, century after century. The groups may still be seen as of
old, fixed and unchanging.
[Illustration: THE PLEIADES.]
What are these stars? Stars and planets have both been spoken about.
There is a great difference between the two.
Perhaps if you were asked whether the sun is most like to a star or a
planet, you would be rather at a loss; and many who have admired the
brilliant evening star, Venus, often to be seen after sunset, would be
surprised to learn that the evening star is in reality no star at all.
A star is a sun. Our sun is nothing more nor less than a star. Each one
of the so-called “fixed stars,” that you see shining at night in the
sky, is a sun like our sun; only some of the stars are larger suns and
some are smaller suns than ours.
The main reason why our sun looks so much larger and brighter than the
stars is, that he is so very much nearer to us. The stars are one and
all at enormous distances from the earth. By and by we will go more
closely into the matter of their distance, compared with the distance
of the sun.
At present it is enough to say that if many of the stars were placed
just as near to us as our sun is placed, they would look just as large
and bright; while there are some that would look a great deal larger
and brighter. And if our sun were to travel away from us, to the
distance of the very nearest of the little twinkling stars, he would
dwindle down and down in size and brilliancy, till at last we should
not be able to tell him apart from the rest of the stars.
I have told you that the stars are called “fixed” because they keep
their places, and do not change from age to age. Though the movement
of the earth makes them seem all to sweep past every night in company,
yet they do not travel in and out among one another, or backwards
and forwards, or from side to side. At all events, if there be such
changes, they are so slow and so small as to be exceedingly difficult
to find out. Each group of stars keeps its own old shape, as for
hundreds of years back.
But among these fixed stars there are certain stars which do go to and
fro, and backwards and forwards. Now they are to be seen in the middle
of one constellation, and now in the middle of another. These restless
stars were long a great perplexity. Men named them Planets or Wanderers.
We know now that the planets are in reality not stars at all, and also
that they are not nearly so far away from us as the fixed stars. In
fact, they are simply members of our own family--the Solar System. They
are worlds, more or less like the world we live in; and they travel
round and round the sun as we do, each more or less near to him; and
they depend upon him for heat and light, in more or less the same
manner as ourselves.
Therefore, just as our sun is a star, and stars are suns, so our earth
or world is a planet, and planets are worlds. EARTH is the name we
give to that particular world or planet on which we live. Planets may
generally be known from stars by the fact that they do not twinkle.
But the great difference between the two lies in the fact that a star
shines by its own radiant, burning light, whereas a planet shines
merely by light reflected or borrowed from the sun.
But how were the earth and the other worlds made? Let us imagine an
immense gaseous mass placed in space. Attraction is a force inherent in
every atom of matter. The denser portion of this mass will insensibly
attract towards it the other parts, and in the slow fall of the more
distant molecules towards this more attractive region, a general motion
is produced, incompletely directed towards this center, and soon
involving the whole mass in the same motion of rotation. The simplest
form of all, even in virtue of this law of attraction, is the spherical
form. It is that which a drop of water takes, and a drop of mercury if
left to itself.
The laws of mechanics show that, as this gaseous mass condenses and
shrinks, the motion of rotation of the nebula is accelerated. In
turning, it becomes flattened at the poles, and gradually takes the
form of an immense lens-shaped mass of gas. It has begun to turn so
quickly as to develop at its exterior circumference a centrifugal force
superior to the general attraction of the mass, as when we whirl a
sling. The inevitable consequence of this excess is a rupture of the
equilibrium, which detaches an external ring. This gaseous ring will
continue to rotate in the same time and with the same velocity; but
the nebulous mother will be henceforth detached, and will continue to
undergo progressive condensation and acceleration of motion. The same
feat will be reproduced as often as the velocity of rotation surpasses
that by which the centrifugal force remains inferior to the attraction.
It may have happened also that secondary centers of condensation would
be formed even in the interior of the nebula.
In our system the rings of Saturn still subsist.
The successive formation of the planets, their situation near the
plane of the solar equator, and their motions of translation round the
same center, are explained by the theory which we are discussing. The
most distant known planet, Neptune, would be detached from the nebula
at the epoch when this nebula extended as far as the planet, out to
nearly three thousand millions of miles, and would turn in a slow
revolution requiring a period of 165 years for its accomplishment. The
original ring could not remain in the state of a ring unless it was
perfectly homogeneous and regular; but such a condition is, so to say,
unrealizable, and it did not delay in condensing itself into a sphere.
Successively, Uranus, Saturn, Jupiter, the army of small planets, Mars,
would thus be detached or formed in the interior of this same nebula.
Afterwards came the earth, of which the birth goes back to the epoch
when the sun had arrived at the earth’s present position. Venus and
Mercury would be born later. Will the sun give birth to a new world?
This is not probable.