Part 13 (1/2)
Noteworthy also was the co 49), discovered at Florence by Donati Its tail extended to a length of 90,000,000 kilometers (55,900,000 miles), and its nucleus had a diameter of at least 900 kilometers (559 miles) It is a curious coincidence that the as remarkably excellent and abundant in that year also
The coia's Comet, in 1874, was also remarkable for its brilliancy, but was very inferior to the last two Finally, the latest worthy of nificent co at a speed of 480 kiloaseous atmosphere of the orb of day, and then continued its course through infinity On the day of, and that following, its perihelion, it could be detected with the unaided eye in full daylight, enthroned in the Heavens beside the dazzling solar luminary For the rest, it was neither that of 1858 nor of 1861
Since 1882 we have not been favored with a visit froive any such a reception worthy of their nificence: first, because now that we have fathoer awestruck; second, because ould gladly study them more closely
In short, these hirsute stars, whose fantastic appearance iination of our ancestors so vividly, are no longer formidable Their mass is inconsiderable; they seeases analysis of their incandescence reveals a spectru that of many nebulae; the presence of carbon is more particularly obvious Even the nucleus is not solid, and is often transparent
It is fair to say that the action of a coht be deleterious if one of these orbs were to arrive directly upon us The transformation of ases with the oxygen of our at of the atmosphere
But the collision of a comet with a planet is almost an impossibility
This phenomenon could only occur if the comet crossed the planetary orbit at the exactWhen we think of the ith of way traversed by a world in its annual journey round the Sun, and the speed of its rotation, we see why this coincidence is hardly likely to occur
Thus, aued, a few only cut the terrestrial orbit One of thehts of October 29 and 30 in that year; but the Earth only passed the same point thirty days later, and at the critical period was more than 80,000,000 kilometers (50,000,000 miles) away from the comet
On June 30, 1861, however, the Earth passed through the extremity of the tail of the Great Comet of that year No one even noticed it The effects were doubtless quite immaterial
In 1872 ere to collide with Biela's Comet, lost since 1852; now, as we shall presently see, we careeable situation, because the corated, and was reduced to powder So we er likely to come to us from comets There is little fear of the destruction of hus
These ethereal beauties whose blond locks float carelessly upon the azure night are not concerned with us; they seem to have no other preoccupation than to race fro new Heavens, indifferent to the astonishment they produce in us They speed restlessly and tirelessly through infinity; they are the Amazons of space
What suns, orlds must they have visited since the itives could relate the story of their wanderings, how gladly should we listen to the enchanting descriptions of the various abodes they have journeyed to! But alas! these mysterious explorers are dumb; they tell none of their secrets, and we matic silence
Yet, some of them have left us a , sufficient, however, to enable us to address our thanks to the considerate er
Can there be any one upon the Earth who has not been struck by the phosphorescent lights that glide through the soolden track--the luht has silently spread the i speck is seen to detach itself in the shades of evening froh the constellations to lose itself in the infinitude of space
[Illustration: FIG 54--A Meteor]
These bewitching sparks attract our eyes and chain our senses
Fascinating celestial fireflies, their dainty fla the fine dust of their gilded wings upon the fields of Heaven They are born to die; their life is only a breath; yet the iination ofin the delicious tranquillity of the transparent night s 54) What can not this adorable star announce to the tender and loving heart? Is it the shydesired? Its unpremeditated appearance fills the soul with a ray of hope and lides into the heart, expanding it in the thrills of a sudden and ephemeral pleasure The radiant meteor seems to quit the velvet of the deep blue sky to respond to the appeal of the i voice that seeks its succor
What secrets has it not surprised! And who bears ainst it? It is the friend of the betrothed who invoke its passage to confide their wishes, and associate it with their drea the visible passage of a meteor it will certainly be fulfilled before the year is out Between ourselves, however, this is but a surviving figination, for this celestial jewel takes no such active part in the doings of Humanity Besides, try to express a wish distinctly in a second!
It is a curious fact that while co stars should on the contrary have been regarded with benevolent feelings at all ti star? These dainty excursionists from the celestial shores are not, as is supposed, true stars They are atoeneral froration of comets They come to us from a vast distance, from millions on millions ofa very elongated ellipse which closely reseht is extre sometimes more than 40 kilometers (25 miles) per second, a coreatly above that of our terrestrial vehicle, which amounts to 29 to 30 kilometers (about 19 miles)
These little corpuscles are not intrinsically luminous; but when the orbit of a swarm of meteors crosses our planet, a violent shock arises, the speed of which reat as 72 kilometers (45 miles) in the first second if we e rate, however, does not exceed 30 to 40 kilometers (19 to 25 miles), for these ht at which they arrive is usually 110 kilometers (68 miles), and 80 kilometers (50 miles) at thestars have been observed at 300 kilometers (186 h up in the atmosphere transforms the motion into heat The molecules incandesce, and burn like true stars with a brilliancy that is often lory is of short duration The excessive heat resulting from the shock consumes the poor firefly; its remains evaporate, and drop slowly to the Earth, where they are deposited on the surface of the soil in a sort of ferruginous dust mixed with carbon and nickel Some one hundred and forty-six milliards of them reach us annually, as seen by the unaided eye, and many more in the telescope; the effect of these showers of meteoric lobe, a slight lessening of its rotary motion, and the acceleration of the lunar h the appearance of shooting stars is a coht of the year, there are certain times when they arrive in swarms, from different quarters of the sky The ust 10th and thestars of August 10th, because they arrive in the fine wareneral contemplation of the Heavens The phenomenon lasts till the 12th, and even beyond, but the maximum is on the 10th When the sky is very clear, and there is nostars can be counted on those three nights, sometimes thousands They all seem to come from the same quarter of the Heavens, which is called the _radiant_, and is situated for the August swarm in the constellation of Perseus, whence they have received the name of _Perseids_ Our forefathers also called them the tears of St Lawrence, because the feast of that saint is on the saated ellipse, and their orbit has been identified with that of the Great Comet of 1862