Speaker 1: Section twenty four of Sun, Moon and Stars Astronomy for Beginners.
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Speaker 1: visit LibriVox dot org. Praad by Prajakta. Sun Moon and
Speaker 1: Stars Astronomy for Beginners by Agnes Gibben. Different kinds of sins,
Speaker 1: great things do at kea which we cannot comprehend, Job
Speaker 1: thirty seven five. Various in kind, various insights, various in color,
Speaker 1: various in position, various in motion. Are the myriad suns
Speaker 1: scattered through space? So far are they from being formed
Speaker 1: on the same plan, turned out on the same model,
Speaker 1: that it may, with reason be doubted whether any two
Speaker 1: stars could be found exactly alike? Why should I expect
Speaker 1: to find them? So no two oak leaves, no two
Speaker 1: elm leaves precisely alike are to be found upon Earth.
Speaker 1: So some stars are large, some are small, Some are
Speaker 1: rapid in movement, some are slow. Some are yellow, some white,
Speaker 1: some red, green, blue, purple, or green. Some are single stars.
Speaker 1: Others are arranged in pairs, tears, quarter teaths, or groups.
Speaker 1: Some appear only for a time, and then disappear altogether.
Speaker 1: Others are changeful, with a light that regularly waxes and
Speaker 1: veins in brightness. We have now give a little time
Speaker 1: and thought to variable stars and temporary stars, afterwards to
Speaker 1: double stars and colored stars. There are many stars which
Speaker 1: pass through gradual and steady changes, first brightening, then less
Speaker 1: in light, then brightening again. One such star is to
Speaker 1: be seen in the constellation of the Veil. It is
Speaker 1: named Mira, or the Marvelous, and the time in which
Speaker 1: its changes take place extends to eleven months. For about
Speaker 1: one fortnight, it is a star of the second magnitude.
Speaker 1: Through three months, it grows slowly more and more dim
Speaker 1: till it becomes invisible not only to the naked eye
Speaker 1: but through ordinary telescopes. About five months it remains thus,
Speaker 1: then again during three months it grows brighter and brighter
Speaker 1: until it is once more a second magnitude star, and
Speaker 1: after a fortnight's pause, begins anew to fade. There is
Speaker 1: also a variable star in the constellation of Perseus, named
Speaker 1: al Goal. The two waxes and vans regularly, but much
Speaker 1: more rapidly, since it runs through its list of changes
Speaker 1: in less than three days. It never becomes brighter than
Speaker 1: a star of the second magnitude or dimmer than a
Speaker 1: star of the fourth magnitude. Another variable star, Beetle Juice
Speaker 1: in Orion, undergoes its variations in about two hundred days,
Speaker 1: while yet another data CAPI takes only six days. Our
Speaker 1: own sun has been reckoned, as in some slight degree
Speaker 1: a variable star passing through his changes in eleven years.
Speaker 1: When the sun spots are most numerous, he might appear, possibly,
Speaker 1: if seen from a great distance, slightly more dim than
Speaker 1: when there are none of them. Sometimes a new or
Speaker 1: temporary star appears, blazing brightly for a brief space and
Speaker 1: then vanishing. It may be a dim star already known,
Speaker 1: which that's brings into a new and radiant phase of being,
Speaker 1: Or it may be practically to us a new existence.
Speaker 1: But doubtless the star was there before, a body too
Speaker 1: faint for us to perceive, and doubtless it is there
Speaker 1: still when the fires of its outbursts die away, once more,
Speaker 1: too faint for its shining to reach our eyes. An
Speaker 1: extraordinary specimen of a temporary star was seen in fifteen
Speaker 1: seventy two. It was not a comet, for it had
Speaker 1: no comma or tail. And it never moved from its place.
Speaker 1: The brightness of the star was so great as to
Speaker 1: surpass Serious and Jupiter, and to equal Venus at her
Speaker 1: greatest brilliancy. Nay, it must have surpassed even Veners, for
Speaker 1: it was plainly visible at midday in a clear sky.
Speaker 1: Gradually the light faded and grew more dim till it
Speaker 1: became a mere faint star. As it lasened in Brilliancy,
Speaker 1: it also changed in color, passing from white to yellow,
Speaker 1: and from yellow to red. This succession agrees with three
Speaker 1: tints of the first, second, and fourth orders of suns,
Speaker 1: as lately classified. Many other instances have been known. Beside
Speaker 1: those referred to of variable and temporary stars. There are
Speaker 1: two distinct kinds of double stars. First, we have those
Speaker 1: which merely seem to be double, because one lies almost
Speaker 1: directly behind the other, though widely distant from it, just
Speaker 1: as a church tower two miles off may appear to
Speaker 1: stand clothes side by side with another church tower two
Speaker 1: and a half miles off, though they are in fact separated. Secondly,
Speaker 1: we have the real systems of two sons belonging to
Speaker 1: one another, the smaller moving round the larger, or more correctly,
Speaker 1: both traveling around one central point called the center of gravity,
Speaker 1: the smaller having the quicker rate of motion. Alpha Centauri
Speaker 1: and sixty one Signy have been already described as examples
Speaker 1: of true double stars. In the constellation Larry, a marked
Speaker 1: instance is to be seen the brightest star in the
Speaker 1: Larry is Vega, and near Vega shines a tiny star which,
Speaker 1: to people with particularly clear sight has sometimes rather a
Speaker 1: longish look. If you examine this star through an opera glass,
Speaker 1: you will find it to consist of two separate stars.
Speaker 1: But if you get a more powerful telescope and look again,
Speaker 1: you will find that each star of the couple actually
Speaker 1: consists of two stars. The four are not at equal distances.
Speaker 1: Two points of light seemingly closed together, are parted by
Speaker 1: a wide gap from two other points equally closed together.
Speaker 1: These four stars are believed to have a double motion.
Speaker 1: Each of the separate pairs revolves by itself the two
Speaker 1: suns traveling around one center, and in addition to this,
Speaker 1: the two couples of suns probably perform a long journey
Speaker 1: around another center common to them all. Many thousands of
Speaker 1: double stars have been discovered, and a large number of
Speaker 1: these are now known to be not merely two distinctions
Speaker 1: lying in the same line of sight, but to brother sons,
Speaker 1: each probably the center of his own system of planets.
Speaker 1: We have not only to consider the number of suns,
Speaker 1: though of simple numbers, more yet remains to be said.
Speaker 1: Attention must also be given to the varying colors of
Speaker 1: different stars. For all suns in the universe are not
Speaker 1: made after the model of arsin all suns are not yellow.
Speaker 1: So far as single stars are concerned, colors seem rather limited.
Speaker 1: White stars, golden or orange stars, ruby raid stars placed
Speaker 1: alone are often seen, but blue stars, green stars, gray stars,
Speaker 1: silver stars, purple stars are seldom, if ever visible to
Speaker 1: the naked eye, are known to exist at single stars.
Speaker 1: Take a powerful telescope and examine star couples, and a
Speaker 1: very different result. You will find not white, yellow, and
Speaker 1: red alone, but blue, purple, gray, green, fawn, buff, silvery, white,
Speaker 1: and coppery youths will delight you in turn. As a rule,
Speaker 1: when the two stars of a couple are alike in
Speaker 1: they are either white or yellow or red. Also, in
Speaker 1: the case of double stars of different colors, the larger
Speaker 1: of the two is almost invariably white or some shade
Speaker 1: of yellow. Or red. There are, however, exceptions to all
Speaker 1: such rules. Blue stars are almost never seen alone, and
Speaker 1: as one of a pair, the blue star is generally,
Speaker 1: if not invariably, the smaller, But instances are known of
Speaker 1: double stars, both of which are blue, and one group
Speaker 1: in the southern Heavens is entirely made up of a
Speaker 1: multitude of bluish sins. It is when we come to
Speaker 1: consider double stars of two colors that the most striking
Speaker 1: effects are found. Now and then, the two suns are
Speaker 1: nearly the same in size, but more commonly one is
Speaker 1: good deal larger than the other. This is known by
Speaker 1: the brighter light of the larger and the more rapid
Speaker 1: movements of the smaller. The laser star is often only
Speaker 1: small by comparison, and maybe in reality a very goodly
Speaker 1: and brilliant sun. Among nearly six hundred doubles examined by
Speaker 1: one astronomer, there were three hundred and seventy five in
Speaker 1: which the two stars were of one color, generally white, yellow, orange,
Speaker 1: or red, the rest very different in tint, the difference
Speaker 1: between the two sons in about one hundred and twenty
Speaker 1: cases being very marked. For instance, a red primary as
Speaker 1: the largest star is called will be seen with a
Speaker 1: small green satellite, or a white primary will have a
Speaker 1: little brother sun of purple, or of dark rubi, or
Speaker 1: of light reed. Sometimes the larger sun is orange, the
Speaker 1: company being purple or dark blue. Again, the chief star
Speaker 1: will be red with a blue satellite, or yellow with
Speaker 1: a green satellite, or orange with an emerald satellite, or
Speaker 1: golden with a reddish green satellite. We hear of golden
Speaker 1: and lilac couples, of cream and violet, pears, of white
Speaker 1: and green companions, But indeed the variety is almost endless.
Speaker 1: There may be worlds circling around these suns, worlds perhaps
Speaker 1: with living creatures on them. We know little about how
Speaker 1: such systems of suns and words may be arranged. Probably
Speaker 1: each sun would have his own set of planets, and
Speaker 1: both suns, with their planets, would travel round one central point,
Speaker 1: perhaps where the second sun is much the smallest. It
Speaker 1: might occasionally be like a big, pleasing satellite among the planets.
Speaker 1: Among colored stars single and double, a few may be
Speaker 1: mentioned by name as examples. Serious, as already observed, is
Speaker 1: a brilliant white sun. The brilliant white also are Vega Canopus,
Speaker 1: Regulus spica, and many others. Capella Prosian, the Pool Star,
Speaker 1: and our own Sun are examples of yellow stars. Aldebaran, Beetle, Juice,
Speaker 1: and Pollux are ruby red, and thees is a red
Speaker 1: star with a greenish scintillation or change of view in
Speaker 1: its twinkling. A tiny green sun belonging to this great
Speaker 1: and brilliant rad sun has been discovered. Antares is sometimes
Speaker 1: called the series of rad suns. The two double stars
Speaker 1: sixty one Signy and Alpha Centauri are formed each of
Speaker 1: two orange sons. In the Southern Cross, there is a
Speaker 1: wonderful group of stars consisting of about one hundred and tensons,
Speaker 1: nearly all invisible to the naked eye. Among the principal
Speaker 1: stars of this group, which Sir John Herschel described as
Speaker 1: being when viewed through a powerful telescope, like a casket
Speaker 1: of variously colored precious stones, are two red stars, two
Speaker 1: bright green, three pale green, and one of a greenish blue.
Speaker 1: End of Section twenty four