Meteor shower

“ The Mazapil, Mexico, iron meteorite fell at 9:00 p.m. on November 27, 1885, during a return of the now very weak Bielid meteor shower. Scientists still cannot decide whether or not a mere coincidence was involved in this case.
As we have already mentioned, most of the cosmic particles rushing into our atmosphere evaporate and do not reach the earth at all except as the tiny congealed droplets and spherules of their own melt. Some cosmic particles, the micro-meteorites, are so tiny that they “stall” rather than fall down. ”

“ But in the case of the meteor-shower of Nov. 27 the motions are extremely slow (about 10 miles per second) , as the Earth and the meteors are travelling nearly parallel in the same direction, and the latter have to overtake the Earth.
Nomenclature of Meteor-Systems.—It is customary to name the showers after the constellation from which the meteors appear to diverge. Thus the meteors of April 20 are called Lyrids, the radiant being in Lyra; the meteors of August 10 are termed Perseids, the point of emanation being in Perseus. ”

“ The conclusion is that the swarm of meteors that forms a comets head is gradually scattered under the distortion produced by the sun and the planets , so as to leave a long trail of meteoric débris, in the wake of the comet. A meteor shower takes plaice when the earth traverses one of these trails ”

“ Apparently, as meteoritic dust particles from the meteor showers filter down through the cloud systems in the lower layers of the atmosphere, the individual particles serve as centers about which atmospheric moisture condenses to form raindrops. The time lag of approximately a month is considered to be due to the very slow rate of fall of such tiny particles. It looks very much as if Mother Nature had beaten man to the idea of “seeding” the clouds to produce rainfall! ”

“ It chanced that just at this period astronomers were paying much attention to a class of bodies which they had hitherto somewhat neglected, the familiar shooting-stars, or meteors. The studies of Professor Newton, of Yale, and Professor Adams, of Cambridge, with particular reference to the great meteor-shower of November, 1866, which Professor Newton had predicted and shown to be recurrent at intervals of thirty-three years, showed that meteors are not mere sporadic swarms of matter flying at random, but exist in isolated swarms, and sweep about the sun in regular elliptical orbits. ”

“ These daytime showers are, of course, invisible in the glare of sunlight, but they can be picked up by radar devices like those used in World War II to spot enemy airplanes.
Some meteor showers have been splendid enough to make a place for themselves in the historical record. Examples are the Leonid returns of 1833 and 1866, and the Giacobinid showers of 1933 and 1946. During these displays, meteors fell in a veritable fiery snowstorm, several hundred meteors sometimes appearing within a minute. ”

“ Generally not a point but a small area, here intentionally exaggerated in size. Solid arrows represent plotted paths of observed meteors. By extending these paths backwards, observer can determine the radiant.
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In the course of each year, the earth passes through a number of particle-swarms of varying densities. Some of the resulting meteor showers, like the Leonids and Giacobinids, are very feeble in most years, but sometimes produce spectacular displays.
The more important recognized meteor showers are:
Certain daytime streams are also known to be active during June and July. ”

“ At the close of a hot, sultry day, over a level country, the igneous meteor often exhibits itself, in rapidly succeeding, broad, noiseless, and imposing sheets of flame, lighting up the whole range of the horizon, revealing for the moment the contour of the distant landscape upon which the shadows of the night have gathered, and discovering the outline of the clouds in the dusky sky. ”

“ Origin of the Light of Meteors.—When one of these meteoroids enters our atmosphere, the resistance of the air arrests its motion to some extent, and so converts a portion of its energy of motion into that of heat. The heat thus developed is sufficient to raise the meteoroid and the air around it to incandescence, and in most cases either to cause the meteoroid to burn up, or to dissipate it as vapor. The luminous vapor thus formed constitutes the luminous train which occasionally accompanies a meteor, and often disappears as a puff of smoke. ”

“ Even without any wind they diffused themselves throughout the meteor’s atmosphere, it was so small a world, with so thin a blanket of air about it—an infinitesimal fraction of the air that envelopes your Earth. ”

“ So they reject the theory that such dust found in the Podkamennaya Tunguska area is specifically connected with the meteorite that fell there a half century ago.
If sizable chunks of meteoritic material enter the atmosphere, they may produce exceptionally large and brilliant meteors. A spectacular meteor is generally known as a “fireball” if it is as bright as Venus or Jupiter. It receives the French term bolide if, in addition to showing great brilliance, its flight is accompanied by detonations like the alarming sounds heard at the time of the Ussuri and Norton meteorite falls. ”

“ From the direction and swiftness of their flight, it is manifest that meteors are visitors from without. They plunge into our atmosphere, and the resistance to which they become then suddenly exposed must raise them to a temperature which exeeds that of the most intense furnace. The heat is enough first to melt and then to dissipate in vapor the most refractory substances, and it only now and then happens that even a part of a meteor escapes this fate, and reaches the ground. They are for the most part lost in vapor ere they get within several miles of us. ”

“ Meteorites, the name for meteors which have actually gone all the way through our atmosphere, are never regular in form or spherical. As a rule the iron meteorites are covered with pittings or thumb marks, due probably to the resistance and impact of the little columns of air which impede its progress, together with the unequal condition and fusibility of their surface material. The work done by the atmosphere in suddenly checking the meteor's velocity appears in considerable part as heat, fusing the exterior to incandescence. ”

“ Aloft, in the emptiness of space, there is no air to impede its flight. It may have been moving round and round the sun for thousands, perhaps for millions of years, without suffering any interference; but the supreme moment arrives, and the meteor perishes in a streak of splendour.
In the course of its wanderings the body comes near the earth, and within a few hundred miles of its surface begins to encounter the upper surface of the atmosphere with which the earth is enclosed. To a body moving with the appalling velocity of a meteor, a plunge into the atmosphere is usually fatal. ”

“ The majority of the meteors we observe represent the heat-induced “evaporation” of exceedingly small fragments of cosmic matter. The smallest meteor-forming bodies reach the surface of the earth only as the finest of dust particles or as microscopic droplets of solidified meteorite melt.
These residues descend slowly through the atmosphere and may be carried for great distances. Afterwards, they may be found scattered so widely and uniformly on the ground that their presence in any given locality cannot be accounted for by the fall of any specific meteorite. ”

“ And if it be true that these meteors have had their origin in solar eruptions, we are brought to the strange reflection, that the matter which in the yesterday of ages was hurled with awful energy from the sun’s surface, is being partly returned to it in the present age, as the energy and matter of to-day will be partly returned to feed its fires in the ages of to-morrow. Should these speculations be correct, then our meteor-systems do indeed play an important part in the economy of nature. ”

“ If it come to an aerolite or mass of metallic rock, or even a cloudlet of gas, standing still in space, its contact with our air evolves 600,000° of heat. And when the meteor comes toward the world twenty-six miles a second, the heat would become proportionally greater if the meteor could abide it, and not be consumed in fervent heat. It vanishes almost as soon as seen. If there were meteoric masses enough lying in our path, our sky would blaze with myriads of flashes of light. Enough have been seen to enable a person to read by them at night. ”

“ Without laying too much stress upon this particular number, we may fairly say that the meteors picked up by the earth every day are to be reckoned by millions, and since they come at all seasons of the year, we shall have to admit that the region through which the earth moves, instead of being empty space, is really a dust cloud, each individual particle of dust being a prospective meteor. ”

“ When the heat subsides, the vapor condenses again into fine dust, so that the ultimate effect of the atmosphere on a shooting star is to grind the little object into excessively fine powder, which is scattered along the track which the object has pursued. Sometimes this powder will continue to glow for minutes after the meteor has vanished, and in the case of some great meteors this stream of luminous dust in the air forms a very striking spectacle. ”

“ Yes, siree, that must have been a big meteor stone."
"Then it struck the earth right close to our camp, mark me," vowed Jud.
"Ain't I glad it didn't pick out this spot to drop on," crowed Nuthin. "Whew! guess we'd have been squashed flatter than that pancake you hear about."
"What are meteors made up of—they drop from stars; don't they?" asked Bob Tice.
"Oh! there's just millions and billions of 'em flying around loose," said Phil Towns, who liked to read of astronomy at times. "Lots of 'em happen to get caught in the envelope of air that surrounds the earth. ”

“ A really large meteor is a grand sight. If it is seen at night it appears as a red star, growing rapidly bigger and leaving a trail of luminous vapour behind as it passes across the sky. In the daytime this vapour looks like a cloud. As the meteor hurls itself along there may be a deep continuous roar, ending in one supreme explosion, or perhaps in several explosions, and finally the meteor may come to the earth in one mass, with a force so great that it buries itself some feet deep in the soil, or it may burst into numbers of tiny fragments, which are scattered over a large area. ”

“ In thus rapidly penetrating the air heat is generated, the meteor becomes incandescent, and the phenomena of the streak or train is produced. Before the object can pierce the dense lower strata of air its material is usually exhausted, but on rare occasions it withstands the fiery ordeal, and fragments of the original mass fall upon the earth.
Multitudes of meteors infest space. On a clear moonless night one person may count eight or ten shooting stars in an hour. ”

“ By careful observation for over fifty years the meteors, generally speaking, have been so arranged that they come under the head of one of the nearly three hundred distinct showers which are now recognized by astronomers.
Many of these showers are too feeble and faint to be worthy of the attention of one not especially interested in the subject, but certain ones are well worth observing. There is always a pleasure in being able to recognize at a glance a certain definite manifestation of nature, be it a rare flower or a flashing meteor. ”

“ The compressed air in which the solid particles of the surface of the meteorite glow then rushes on all sides, but especially over the surface of the meteor behind it, where it encloses a pear-shaped vacuum which has been left by the meteorite, and so appears to the observer as a ball of fire. If several bodies enter the earth's atmosphere in this way at the same time, the largest among them precedes the others, because the air offers the least resistance to its proportionately smallest surface ”

“ Falling stars are counted by watchers, succeeding each other through the night; and every extraordinary meteor is regarded as a curse, because the sign of a curse. Every deficient inundation is held to be preceded by fiery signs in the sky; or, as philosophers put it, by sultry weather. If the meteors tended towards the south, indeed, all might be well, because it portended a north wind, favourable to the inundation; but if they flew all abroad, or darted northwards, calamity might be looked for. ”

“ We have met with outbursts upon stars sometimes of sufficient violence to shoot off part of their substance. We have found the gaseous portion sweeping through space like a net, and the vapors that accompanied it condensed into spatters that have consolidated into meteorites. We have seen this system traveling through boundless space, with nothing near it except an occasional solitary meteor, and we have seen it in the long lapse of ages slowly augmenting its cluster of these little strangers. ”

“ Even before we reached it we saw pieces of meteoric iron scattered about, seeming to bear out the theory of our scientists that the meteor struck here, exploded, and blasted the hole into which it fell, leaving the great rim of upturned earth two hundred feet high that constitutes the mound. ”

“ They are presumably cold and invisible when they enter the earth’s atmosphere, and become heated and visible during their passage through the air; doubtless the greater part of the superficial material flicks off as the result of the sudden heating and is left behind floating in the air as the trail of the meteor. ”

“ If the process went on for long the meteor would be all dissipated in vapour, and in any case it must reach the earth considerably reduced in size.
Numbers and numbers of comparatively small ones disappear, and for every one that manages to come to earth there must be hundreds seen only as shooting stars, which vanish and 'leave not a wrack behind.' When a meteor is seen to fall it is traced, and, whenever possible, it is found and placed in a museum. Men have sometimes come across large masses of stone and iron with their surfaces fused with heat. ”