Show ALLEYS ALL Vs V's COMET f By FREDERIC CAMPBELL Sc Sr D. D president resident of the Department of Astronomy Brooklyn Institute t ft t. 1009 1919 by Frederic Campbell re Ceding articles we ha have vc in in- iato ito the th app appearance distances Sots dates datt course CO and aud history it t stupendous object object- t Hallos Hallo's thick is Ju just t it its a to i it over ocr our guilty for or at months It is h now no tin timo t to toD tola la II D Investigation into the nature an nn obi object t impressive he thing about n Comet loD ftc sweeping pin tail Ha II 0 I e n to 10 reach a length of 4 4 a wb ch is equal I In to n rr line Ilse of hf full lull moon n. n In n appearance this a n searchlight which cast I r rt landscape illumines all tho the I t articles of ot du dust t and moisture I hap happen peen n in its fir it way wad W I icing giving an nn anion ion men of e t far J a It t ill is IK perfectly easy cal for or a walk wilk th time the h beam ai of or a 1 aCht Cht fht and to throw brow itt its full forgo fono oro falling l leaf at would riot not di disturb b h he i so o with a comets comet's I II is ono one of the tho most tan D W in lo tho uni er universe l' l The Tho it UD n be lH distinctly seen through h hof of miles mih of its ih thickness s. s On 1819 tko the earth passed through ta t tall Ull without any result rho Tho v ak vacuum secured in the tho la labi lab lab- i- i r 3 dh Js is rt- rt Regarded as ns solid millstone red t i with the c density d dc of n a com corn II l- l lU It U ill is ix therefore manifest that I C zo upon such nn on obil l upon next to nothing nothings course it rt is is something and in in f. f t bole Jom Tom an October 12 old 1 L I order to know what it is if wo we 10 must study tho the nature of tho the comets comet's head froma from a which bich it proceeds proceed The solid part heart of a Ii comet is its nucleus nu dens cleus or core This Thi is at nt tho center r of or its hea head and shows 5 more brightly than the thc rp rest t A lari largo o n part of the head is i nearly nuh as 18 unsubstantial as is the tho tail nail and ma may may bo be likened to steaming Because c of oC tho the nature of ot these I it SM is difficult to secure nn an accurate measurement ment of tho the nucleus as 8 it would be to judge e of the tho size sizo of skull beneath its corona of waving wa hair lint But when Professor Charles A. A Young says pays that tho the mass of the tho head head of an anai ai a large Jarge comet like s nm may bo hI regarded as ns equal to a hall ball of iron of l lr 0 O miles' miles diameter it is manifest that here w we have havo something truly sub suh The nucleus then is the real comet And t this his f is conceived of not as ns a solid flolid sphere but as a mass mas of objects ob jests of uncertain size eize held together October 2 2 29 1835 1635 From Froin an old drawing b by th m u gravitation r and all mO moving under unde the thc influence of the tho sun situ Where these camp came from and bow how thc they happened to be no ouo s. ws But the substances of which Ule they are composed are arc identical with elements clements with which bich wp wo are arc familiar Hydro Hydrocarbons carbons and various metals respond to spectroscopic copic iron tests tests iron ma magnesium and etc and ns as matters develop with tho the approach of a comet omet to tho the sun star tho the hydrocarbons break ak up into soot and smoke which ia its illuminated by the sunlight in f it travels b Far ar away the comet displays no DO light nor tail the tho influences of the sun are arc felt too top feebly at so 50 great creat distance But with ith the over er increasing speed peed of ot its approach there is a rapid increase of the suns sun's suns ener energy energy- imparted to it so 1 that the nucleus hitherto cold and dark develops its hnz hazy hud head and is first seen scow as an indistinct nebula then the taU tall is thrown out and developed aa at w well n ns as more mor fun fully displayed by reason reason rea rca son on of or Its its scar near D approach Since the thc earth lies so 50 n near ar the tho sun Aun in the time celestial celestial celes celes- vastness tho time comet approaches J s sun and earth arth at It the thc same time hence henc at first its tail taB lies s 's behind the tho head andis and is seen nearly lengthwise e lint but when it passes our globe globo in eith either r wo 0 view it it sidewise o and obtain 10 tho the full fun benefit t of its entire length cn t h of millions of miles Tho development of tho the tail i is duo duoto duoto to t the thc bc rapid bpi increase c- c cof of solar heat and andr d r n I 4 h HaUey's Halley's Comet January 28 1836 1630 From an old drawing perhaps of ot electricity dr driving drin in out ea gases cs from from the thc which are aro repelled in space As An the thc tail is it always turned away may from the thc sun i is clear that some force proceeding from the tho sun Jilin is is accountable for it It cannot bo be like a trail of ot steam or smoke loft left behind a locomotive for the comet does not travel tra in an any resisting mediums medium and is I actually preceded it by its tail when re retreating treating into space I One of ot our most host recent discoveries is that of tho force exerted by light licht it it- roel self Xo No less K than tons tonIJ of light 1 pressure are arc received IJ by the earth carth from tram the thc sun and its ls law is is that this I force rapidly ialy with the division di di- ru vision isio 0 of tho the object t into smaller r par tics ticks The Thc substances expelled how from tho the nucleus of at a 1 comet bv by t the the he sun un ron eon tho most finely divided d matter conceivable abe hen hence e the tho the mot most t sensitive C to time thc action achon of light Sonic Some think that I there thero is an actual bombardment of these particles by bJ corpuscles proceed proceed- proceeding lag ing from front the thc sun un with enormous speed Hence the back they are arc swept into space in tho the form of a tail t hoso light is il chien chiefly if not wholly holh reflected sunlight sun sun- li light ht while that of a tho head bend is partly parti- reflected and partly the outcome of ot energies en n set into action by the thc suns sun's in in- fluence Comets sometimes run so close c to tho sun Bun that they Bro are torn torn io to pieces b by the thc tidal influence of its tremendous ital gravitation oo s co comet pct is its one oft of t 4 thc these e. e gone ODe beyond crr and anil now supplanted b by bytho tho the stream of Bi meteors fonow following n its t former course course The ThC io great rat comet come of ran so IiO o near The Thc e sun suu as to brush brugh its coronal streamers stream era cis ers and lit ht go so felt the force of the suns sun's suns attraction when hen so JO close that it went to pieces before our eyes ejes breaking breaking break break- ing inc into no Jc less s than five fife separate comets cornets com corn ets CtR each ench throwing out nut its it tail after the thc pattern nf of the thc original It is il thus t that ha t in a number of or in c streams streams' arc are recognized zed as al the remnants r Comparative Comparativo sizes of or Neptune and the earth To Neptune Neptuno is given the honor honorof of or having captured Kalley's Halley's comet Drawn by the tho author of old cornets comets feebly pursuing n tho the old paths and steadily t exhausting themselves them solves selves by bv self helf immolation in time the earths earth's atmosphere Dr graphically demonstrated the relation of meteors meteor to comets comet on ono one occasion ho lie extracted ex ox r gases from meteorites that had bad fallen to earth arth anc and with t then them em illuminated the tho theatre of the tho Royal institution |