Speaker 1: Section twenty eight of Sun, Moon and Stars Astronomy for Beginners.
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Speaker 1: Moon and Stars Astronomy for Beginners by Agnes Giburne.
Speaker 2: Further thoughts.
Speaker 1: My right hand hath spanned the Heavens Isaiah.
Speaker 2: Forty eight thirteen.
Speaker 1: Early in the year eighteen ninety two, a new star
Speaker 1: appeared in the constellation or Riga, winning much attention. On
Speaker 1: December tenth, eighteen ninety one, it made its first appearance
Speaker 1: suddenly as a star of the fifth magnitude. Two days earlier,
Speaker 1: no stars so bright as even the ninth magnitude had
Speaker 1: been visible in that of the Heavens. On the twentieth
Speaker 1: of December, it reached its brightest. On the eighth of February,
Speaker 1: it was again only a star of the fifth magnitude,
Speaker 1: and after the seventh of March there were remarkable swayings
Speaker 1: to and fro of the intensity of the light, set
Speaker 1: up probably by commotions attendant on the cause of its outburst.
Speaker 1: These lessened and the star fell steadily to only the
Speaker 1: eleventh and then by the first of April to the
Speaker 1: fourteenth magnitude. At the end of April, it was still
Speaker 1: faintly visible. Nova Oregae, as this brilliant stranger has been named,
Speaker 1: showed under the spectroscope a rainbow tinted ribbon in which
Speaker 1: splendid groups of bright lines stood out from a paler background.
Speaker 1: The red ray of hydrogen flower hoffers Sea glowed like
Speaker 1: a danger signal on a dark night. A superb quartet
Speaker 1: of rays shone in the green. Shimmering blue bands and
Speaker 1: lines drew the eye far up towards the violet. The
Speaker 1: characteristic blazing spectrum in fact of a new star was
Speaker 1: unmistakably present. The interpretation left no doubt that hydrogen played
Speaker 1: a large part in the conflagration.
Speaker 2: Nor was this all that.
Speaker 1: The spectroscope had to say. At the close of the
Speaker 1: last chapter, brief mention was made of the mode in
Speaker 1: which the coming nearer or passing away of a star
Speaker 1: may be discovered. With the spectrum of Nova Origai, an
Speaker 1: extraordinary thing was seen. There were distinct and unmistakable signs,
Speaker 1: not of approach alone or of a receding movement alone,
Speaker 1: but of both simultaneously At one and the self same moment,
Speaker 1: the nova appeared to be speeding away from us at
Speaker 1: a rate of two or three hundred miles per second,
Speaker 1: and rushing towards us at much the same rate, the
Speaker 1: sum of the two motions together amounting to no less
Speaker 1: than about five hundred and fifty miles per second. At first,
Speaker 1: this was explained by a conjecture that Nova O Regae
Speaker 1: might consist of two stars, one of the two hurrying
Speaker 1: towards us and the other hurrying away from us. But
Speaker 1: the two star explanation is already being given up, and
Speaker 1: astronomers are inclined to think that the rush to and
Speaker 1: fro is probably only of heated gases on the turbulent
Speaker 1: surface of the star. For Nova OU Regae, like many
Speaker 1: or most other stars, is most likely a mass of
Speaker 1: intensely heated and glowing gases forcibly compressed within by gravitation
Speaker 1: and spreading outside far away into a furiously excited, incandescent atmosphere.
Speaker 1: In any case, the history of the nova is a
Speaker 1: remarkable one, and apparently we have not yet come to
Speaker 1: the end of it. After steadily waning to a very
Speaker 1: faint star, it has begun again to increase in brightness.
Speaker 1: What course it will follow in the future. Time alone
Speaker 1: can show mention has more than once been made in
Speaker 1: this revised edition of the Probable Presence and Absence of
Speaker 1: atmospheres on different Heavenly bodies, and of apparent reasons for
Speaker 1: the same.
Speaker 2: An atmosphere is formed.
Speaker 1: Of gas particles or gas molecules in rapid motion. There
Speaker 1: are different gases, and the particles of one gas differ
Speaker 1: in speed from those of another gas. Moreover, the colder
Speaker 1: any gases, the more slowly its particles move. The hotter
Speaker 1: any gas, the more vehemently its tiny molecules dash to
Speaker 1: and fro, incessantly striking against other molecules and striving to escape.
Speaker 1: If this is the case with our atmosphere, why should
Speaker 1: not all the particles of air escape in the course
Speaker 1: of time, passing into distant space and forsaking us utterly.
Speaker 1: So unquestionably they would do, but for the restraining force
Speaker 1: of gravitation. Struggle as they may to get away, Earth's
Speaker 1: strong attraction holds them in leash, and they cannot flee.
Speaker 1: Our atmosphere consists mainly of oxygen and nitrogen, and the
Speaker 1: oxygen gas is essential for animal life. No free hydrogen
Speaker 1: gas floats in our atmosphere, although enormous quantities of it
Speaker 1: are present in the Sun. It is very possible that
Speaker 1: once upon a time Earth possessed hydrogen gas also in
Speaker 1: her air, and that she has lost it since, for
Speaker 1: the particles of hydrogen are exceedingly rapid in their motions,
Speaker 1: far more so than the particles of oxygen or nitrogen. Therefore,
Speaker 1: they need a much stronger restraint to hold them in.
Speaker 1: And while Earth is large, judge and dense enough to
Speaker 1: keep her nitrogen and oxygen gases prisoners, she has not
Speaker 1: it would seem sufficient attractive power to hold in hydrogen.
Speaker 1: If Mars has an atmosphere or mercury, we may say
Speaker 1: with tolerable confidence that no free hydrogen exists in it,
Speaker 1: because neither Mars nor Mercury could be expected to hold
Speaker 1: fast the rapidly journeying particles of hydrogen gas. It has
Speaker 1: even been calculated that very probably Mars is somewhere about
Speaker 1: the smallest world which can permanently retain an atmosphere. We
Speaker 1: have already seen that the Moon, so far as we
Speaker 1: can discover, has no atmosphere. If ever, the Moon did
Speaker 1: possess one, it has doubtless all wandered away because her
Speaker 1: attractive power was too weak to keep it.
Speaker 2: This is not merely a guess.
Speaker 1: The speed of different gas particles is accurately known, and
Speaker 1: the strength of gravitation needed to control them is known. Also,
Speaker 1: it is no difficult matter to find out about how
Speaker 1: heavy a world must be to overcome by attraction the
Speaker 1: impetus of the busy little gas molecules. But while the
Speaker 1: Moon perhaps could not keep any atmosphere, and while the
Speaker 1: Earth might be unable to hold in bondage an atmosphere
Speaker 1: of hydrogen gas, the Sun has no such difficulty. His
Speaker 1: enormous bulk gives such enormous attractive power that the hydrogen
Speaker 1: in his atmosphere, though violently heated and furiously excited, is
Speaker 1: still under control. A most natural, though wide step carries
Speaker 1: us from the restless gas particles breaking loose from control,
Speaker 1: to the larger, restless heavenly bodies, which appear to do.
Speaker 2: Precisely the same thing.
Speaker 1: In our Solar system, we have worlds and satellites, comets
Speaker 1: and meteors are under the Sun's command, obedient to his
Speaker 1: attractive power. We have also wandering comets, occasional and passing visitants,
Speaker 1: traveling at so rapid a pace that all the great
Speaker 1: attraction of the Sun fails utterly to hold them in,
Speaker 1: and they plunge into the depths of space, never to return.
Speaker 1: In our stellar system we have countless suns, double stars, clusters,
Speaker 1: and perhaps nebulae, subject one to another, bound together by
Speaker 1: the bonds of mutual gravitation. But also we have possibly
Speaker 1: runaway stars, wanderers from the depths beyond, passing through our
Speaker 1: starry system at a headlong rush, which it may be
Speaker 1: not all the combined control of all the stars of
Speaker 1: light can check or hinder. If so, they doubtless will
Speaker 1: plunge into profounder distances beyond the utmost stretch of human imagination,
Speaker 1: never to return. Verily, the great things and the little
Speaker 1: things of creation are subject to the same laws. A
Speaker 1: few closing words as to the possible comparative ages of
Speaker 1: different heavenly bodies.
Speaker 2: May be of interest.
Speaker 1: The ages of worlds and sons cannot indeed be reckoned
Speaker 1: by years or by centuries. No record gives us the
Speaker 1: date in past millenniums of the birth of this or
Speaker 1: that bright orb. Yet looking upon them. From our little
Speaker 1: world we see signs which seem to tell in one
Speaker 1: of comparative youth, in another of comparative age. Nay, so
Speaker 1: marked to these signs, and so evidently is one stage
Speaker 1: succeeded by another stage, that, as in looking on boy
Speaker 1: and man, we may say with confidence that the one
Speaker 1: has been or the one will be, just like the other,
Speaker 1: so in looking on diverse heavenly bodies we may conjecture
Speaker 1: that as one is, another has been or will be.
Speaker 1: Positive assertions are indeed, here, as elsewhere, out of place.
Speaker 1: Watching the heavens as we do, with limited sight and
Speaker 1: for a very brief span, it behooves us to be careful,
Speaker 1: even in conjecture. Though the marvel is that we can
Speaker 1: know so much. Though the question may well be asked,
Speaker 1: what then must the true nature of that mind be
Speaker 1: which thus freely associates itself with the things beyond the stars.
Speaker 1: Surely it must find its natural home among the infinite,
Speaker 1: the infinitely remote, both in space and in time. Still, caution,
Speaker 1: linked with humility, must be our watchword, for the utmost
Speaker 1: that we know is as nothing compared with the vast
Speaker 1: regions beyond which we do not know Still, the more
Speaker 1: yonder heavens are searched, the more it does appear that
Speaker 1: development takes place among those shining hosts, even as among
Speaker 1: the little existences on Earth, our Moon, for instance, seems
Speaker 1: to be a very old and used up world. Old
Speaker 1: not so much in centuries or millenniums, as in having
Speaker 1: reached a certain decrepit and worn out phase of existence.
Speaker 1: One man is old and another is young at sixty
Speaker 1: in actual decades of centuries, the Moon may reckon no
Speaker 1: more recurring birthdays than Earth or Sun, but in the
Speaker 1: social standing of the skies, she is or seems to
Speaker 1: be very elderly, very much paid out, almost a dead world.
Speaker 1: Once upon a time, doubtless, the Moon was a shining
Speaker 1: mass of rotating gases, vague and nebulous in form, and
Speaker 1: that was her extreme youth, her infancy, so to speak.
Speaker 1: For her actual birth, one would have to go farther back. Still, then,
Speaker 1: through ages, as gravitation drew the masses of gas nearer,
Speaker 1: she probably grew into a tiny sun or star, with
Speaker 1: a radiant photosphere and an atmosphere of heated gases in commotion.
Speaker 1: So tiny a sun would cool quickly, and by and
Speaker 1: by the radiance would die out as the little orb
Speaker 1: passed from vigorous youth to early middle life, reaching the
Speaker 1: present heated and molten but not luminous condition of Jupiter,
Speaker 1: after which would follow the advanced middle age, such as
Speaker 1: our Earth has now attained to, though if the Moon
Speaker 1: had by that time lost her atmosphere, it could not
Speaker 1: well be an inhabited stage. Lastly, she has gained her
Speaker 1: present half dead phase of extreme old age. The Sun
Speaker 1: is young, still in the very heyday of his existence,
Speaker 1: though now a huge, shapely ball with a photosphere of
Speaker 1: radiant clouds and an envelope of heated gases. He was
Speaker 1: probably once upon a time a vast nebula of revolving gases,
Speaker 1: like such nebulae as we see now in the skies.
Speaker 1: A mutual attraction drew the gas particles slowly together. His
Speaker 1: enormous hazy bulk gradually lessened and took a definite form.
Speaker 1: But still he continues and will steadily continue to lessen
Speaker 1: in size, and this shrinkage is conjectured to cause the
Speaker 1: heat from which springs his glowing radiance. By and by,
Speaker 1: after countless ages, he may be expected to cool down further,
Speaker 1: yet first to a molten and then to a solid body,
Speaker 1: no longer giving out light or heat. Jupiter has passed
Speaker 1: from the gaseous and radiant to the heated but non
Speaker 1: luminous condition. Earth, being smaller, has cooled and shrunk more
Speaker 1: rapidly than Jupiter, though by no means so rapidly as
Speaker 1: the still smaller Moon. Thus, in Sun Jupiter, Earth, Moon,
Speaker 1: we seem to see four distinct stages of star life.
Speaker 1: The radiant figure of youth, the calmer warmth of manhood,
Speaker 1: the composed usefulness of middle age, the used up chilliness
Speaker 1: of extreme old age.
Speaker 2: This may have been, and seemingly to.
Speaker 1: Us it has been, the mode in which our God, gradually,
Speaker 1: stage by stage, made the stars and framed the worlds
Speaker 1: which float in the universe.
Speaker 2: These few paces have been trodden, step by step.
Speaker 1: We have advanced from the first early notion of our
Speaker 1: Earth as the mighty center of the universe, to a
Speaker 1: stage where Earth and planets vanish from sight, and the
Speaker 1: great central Sun of our system himself shines forth, but
Speaker 1: as one glimmering.
Speaker 2: Point of light amid a million stars.
Speaker 1: Well, may we say, in the words of the inspired writer,
Speaker 1: as we gaze on the wonders of God's glorious creation.
Speaker 1: When I consider thy heavens, the work of thy fingers,
Speaker 1: the moon and the stars which thou hast ordained. What
Speaker 1: is man that thou art mindful of him? And the
Speaker 1: son of Man that thou visitest him? And yet there
Speaker 1: is another side to the matter. Infinite in power, God
Speaker 1: is also infinite in love, mighty in the creation of
Speaker 1: his vast and blazing suns, He is no less mighty
Speaker 1: in the creation of a blade of grass. The rushing
Speaker 1: stars of a universe are in his hand, but not
Speaker 1: as sparrow on Earth may fall to the ground without
Speaker 1: his knowledge. He guides each distant sun in its pathway
Speaker 1: through the sky. And also he looks from his throne
Speaker 1: of light to ponder the ways of man. He tends
Speaker 1: his countless furnaces of fire and flame. Yet the very
Speaker 1: hairs of your head are all numbered. Let us look
Speaker 1: into the matter as we will, Let us weigh, measure, calculate.
Speaker 1: Let us find our earth to be but as a
Speaker 1: grain of fine dust, lost amid myriads of worlds and suns.
Speaker 1: Still at the close of all we stand face to
Speaker 1: face with the simple historical fact that the King of Heaven.
Speaker 1: The creator of the universe himself, lived as man for
Speaker 1: thirty three years upon Earth, died upon Earth, rose from
Speaker 1: death upon Earth, and went up again from Earth to
Speaker 1: Heaven that sheds a distinguishing radiance upon our earth, which
Speaker 1: it may well be. No other world in all the
Speaker 1: universe can rival. Thou art worthy, O Lord, to receive
Speaker 1: glory and honor and power, For thou hast created all things,
Speaker 1: and for thy pleasure they are and were created. Revelations
Speaker 1: four eleven, end of Section twenty eight. End of Sun,
Speaker 1: Moon and Stars. Astronomy for Beginners by Agnes Gibburn