{"id":19015,"date":"2021-06-11T18:14:40","date_gmt":"2021-06-11T18:14:40","guid":{"rendered":"https:\/\/uni.hi.is\/einar\/?p=19015"},"modified":"2021-06-11T18:14:40","modified_gmt":"2021-06-11T18:14:40","slug":"stjarnedlisfraedi-og-heimsfraedi-a-islandi-3-timabilid-1870-1930-a-nyja-stjornufraedin-berst-til-landsins","status":"publish","type":"post","link":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/?p=19015","title":{"rendered":"Stjarne\u00f0lisfr\u00e6\u00f0i og heimsfr\u00e6\u00f0i \u00e1 \u00cdslandi 3: T\u00edmabili\u00f0 1870-1930 (a) N\u00fdja stj\u00f6rnufr\u00e6\u00f0in berst til landsins"},"content":{"rendered":"

Yfirlit um greinaflokkinn<\/a><\/p>\n

Eins og fram kom \u00ed fyrri f\u00e6rslu<\/a>, m\u00e1 rekja s\u00f6gu stjarne\u00f0lisfr\u00e6\u00f0innar r\u00fam 400 \u00e1r aftur \u00ed t\u00edmann, til upphafs \u00feeirrar fr\u00e6\u00f0igreinar, sem vi\u00f0 n\u00fa k\u00f6llum kennilega stjarne\u00f0lisfr\u00e6\u00f0i<\/em>. Hins vegar l\u00edta margir sagnfr\u00e6\u00f0ingar og stjarnv\u00edsindamenn svo \u00e1, a\u00f0 n\u00fat\u00edma stjarne\u00f0lisfr\u00e6\u00f0i<\/a> hafi fyrst komi\u00f0 til s\u00f6gunnar um mi\u00f0bik n\u00edtj\u00e1ndu aldar, \u00feegar n\u00fd t\u00e6kni, bygg\u00f0 \u00e1 e\u00f0lisfr\u00e6\u00f0i og efnafr\u00e6\u00f0i, ger\u00f0i m\u00f6nnum kleift a\u00f0 taka lj\u00f3smyndir<\/a> af fjarl\u00e6gum stjarnfr\u00e6\u00f0ilegum fyrirb\u00e6rum og sko\u00f0a og t\u00falka litr\u00f3f<\/a> \u00feeirra. Nafni\u00f0 stjarne\u00f0lisfr\u00e6\u00f0i (\u00fe. Astrophysik) mun og fyrst hafa s\u00e9st \u00e1 prenti \u00e1ri\u00f0 1865, \u00ed riti \u00fe\u00fdska e\u00f0lisfr\u00e6\u00f0ingsins K. F. Z\u00f6llners<\/a> um lj\u00f3sm\u00e6lingar<\/a>.<\/p>\n

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Fyrsta lj\u00f3smyndin af yfirbor\u00f0i s\u00f3lar<\/span><\/a> var tekin\u00a0 me\u00f0 Daguerre-t\u00e6kni<\/a> \u00e1ri\u00f0 1845. \u00dear voru a\u00f0 verki fr\u00f6nsku e\u00f0lisfr\u00e6\u00f0ingarnir Hippolyte Fizeau<\/a> og L\u00e9on Foucault<\/a>. Au\u00f0veldlega m\u00e1 sj\u00e1 s\u00f3lbletti \u00e1 myndinni.<\/span><\/figcaption><\/figure>\n
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Hin fr\u00e6ga handlita\u00f0a teikning lj\u00f3sfr\u00e6\u00f0ingsins Josephs Fraunhofer<\/a> af litr\u00f3fi s\u00f3lar fr\u00e1 1814-15. Rau\u00f0i liturinn hefur lengstu bylgjulengdina, en s\u00e1 fj\u00f3lubl\u00e1i stysta. Greinilega m\u00e1 sj\u00e1 d\u00f6kku l\u00ednurnar<\/a> \u00ed annars samfelldu s\u00f3larr\u00f3finu. Ferillinn fyrir ofan s\u00fdnir mat Fraunhofers \u00e1 hlutfallslegum styrk s\u00f3larlj\u00f3ssins \u00e1 mismunandi bylgjulengdum. N\u00e6r 45 \u00e1r \u00e1ttu eftir a\u00f0 l\u00ed\u00f0a \u00fear til menn \u00e1ttu\u00f0u sig \u00e1 merkingu litr\u00f3fsl\u00ednanna. Mynd: Deutsches Museum.<\/span><\/figcaption><\/figure>\n

 <\/p>\n

\u00cdhaldss\u00f6m vi\u00f0horf fyrri t\u00edma<\/span>
\n<\/strong><\/h3>\n

\u00cd upphafi greinar sinnar fr\u00e1 1931, Um byggingu stjarnanna<\/a>, segir Trausti Einarsson stjarne\u00f0lisfr\u00e6\u00f0ingur, \u00fe\u00e1 vi\u00f0 n\u00e1m \u00ed G\u00f6ttingen<\/a>:<\/p>\n

Fyrir frj\u00f3sama samvinnu stj\u00f6rnufr\u00e6\u00f0i og e\u00f0lisfr\u00e6\u00f0i hefur \u00e1 seinustu t\u00edmum fengist m\u00f6rg s\u00fa vitneskja um himingeiminn, r\u00fami\u00f0 umhverfis okkur, sem fyrri t\u00edma menn hefur ekki \u00f3ra\u00f0 fyrir, e\u00f0a \u00feeir jafnvel haldi\u00f0 \u00f3m\u00f6gulega.<\/p>\n

Um 1850 l\u00e9t franskur heimspekingur \u00feess geti\u00f0, a\u00f0 \u00fe\u00f3tt mannsandinn hafi sigrast \u00e1 margri \u00ferautinni, v\u00e6ri a\u00f0 minnsta kosti til ein, sem hann myndi ekki geta leyst: Menn myndu aldrei geta fengi\u00f0 neina vitneskju um efnin og \u00e1stand \u00feeirra \u00e1 stj\u00f6rnunum.<\/p>\n

\u00deessi g\u00f3\u00f0i heimspekingur f\u00f3rna\u00f0i s\u00e9r fyrir \u00fearft m\u00e1lefni. Hann gaf m\u00f6nnunum ford\u00e6mi \u00feess, hve of almennar sta\u00f0h\u00e6fingar eru varasamar. \u00dev\u00ed sk\u00f6mmu s\u00ed\u00f0ar var grundv\u00f6llur lag\u00f0ur a\u00f0 n\u00fdrri grein e\u00f0lisfr\u00e6\u00f0innar, fr\u00e6\u00f0inni um litr\u00f3fi\u00f0, og leysti h\u00fan einmitt \u00ferautina.<\/p><\/blockquote>\n

\u00dearna er \u00f3beint veri\u00f0 a\u00f0 v\u00edsa til or\u00f0a\u00a0\u00c1g\u00fasts Comte<\/a> \u00ed n\u00edtj\u00e1ndu lex\u00edu b\u00f3kar hans,\u00a0 Cours de philosophie positive II<\/a>, fr\u00e1 1835, en \u00fear segir me\u00f0al annars \u00ed lauslegri endurs\u00f6gn minni:<\/p>\n

Um stj\u00f6rnurnar er \u00fea\u00f0 a\u00f0 segja, a\u00f0 okkur er einfaldlega \u00f3m\u00f6gulegt a\u00f0 gera \u00e1 \u00feeim a\u00f0rar\u00a0 ranns\u00f3knir en \u00fe\u00e6r, sem \u00e1 endanum eru l\u00edti\u00f0 anna\u00f0 en athuganir me\u00f0 berum augum.\u00a0 Vi\u00f0 getum l\u00e1ti\u00f0 okkur dreyma um a\u00f0 finna l\u00f6gun \u00feeirra, st\u00e6r\u00f0 og hreyfingu, en vi\u00f0 munum aldrei geta \u00e1kvar\u00f0a\u00f0 efnasamsetningu \u00feeirra e\u00f0a efnabyggingu. […]<\/em> \u00deekking okkar \u00e1 loftkenndum hj\u00fapum \u00feeirra mun takmarkast vi\u00f0 tilvist, st\u00e6r\u00f0 og lj\u00f3sbrotseiginleika, en efnasamsetninguna og jafnvel \u00fe\u00e9ttnina mun okkur ekki takast a\u00f0 \u00e1kvar\u00f0a. […]<\/em> \u00c9g tel og, a\u00f0 vi\u00f0 munum aldrei geta m\u00e6lt hitasig einstakra stjarna.<\/p><\/blockquote>\n

\u00cd gegnum t\u00ed\u00f0ina hafa margir gert gr\u00edn a\u00f0 or\u00f0um Comtes og yfirleitt er \u00e1 \u00feau minnst \u00ed ritum um upphafs\u00e1rin \u00ed s\u00f6gu stjarne\u00f0lisfr\u00e6\u00f0innar.\u00a0 M\u00e1li\u00f0 er \u00fe\u00f3 ekki jafn einfalt og \u00fea\u00f0 vir\u00f0ist \u00ed fyrstu. Comte var \u00e1g\u00e6tlega uppl\u00fdstur um stj\u00f6rnufr\u00e6\u00f0i og e\u00f0lisfr\u00e6\u00f0i s\u00edns t\u00edma, og hefur \u00e1n efa \u00feekkt til r\u00edkjandi hugsunarh\u00e1ttar me\u00f0al franskra stj\u00f6rnufr\u00e6\u00f0inga. \u00de\u00f3tt hann nefni kannski \u00f3\u00fearflega m\u00f6rg sm\u00e1atri\u00f0i \u00ed yfirl\u00fdsingum s\u00ednum um stj\u00f6rnurnar, ber a\u00f0 hafa \u00ed huga, a\u00f0 vel fram yfir mi\u00f0ja n\u00edtj\u00e1ndu \u00f6ld munu stj\u00f6rnufr\u00e6\u00f0ingar almennt hafa veri\u00f0 \u00feeirrar sko\u00f0unar, a\u00f0 e\u00f0li stjarnanna yr\u00f0i m\u00f6nnum sennilega hulin r\u00e1\u00f0g\u00e1ta um \u00f3fyrirsj\u00e1nlega framt\u00ed\u00f0.<\/p>\n

D\u00e6mi um \u00feetta vi\u00f0horf m\u00e1 reyndar finna mun fyrr, me\u00f0al annars \u00ed latneskri disp\u00fatat\u00edu G\u00edsla \u00deorl\u00e1kssonar, De stellis fixis et errantibus<\/a> fr\u00e1 1651. \u00dear segir \u00ed \u00e1ttundu grein:<\/p>\n

En erfi\u00f0ara vandam\u00e1l var\u00f0ar e\u00f0li og verkan stjarnanna og \u00fev\u00ed getum v\u00e9r ekki gengi\u00f0 fram hj\u00e1 \u00feurrum f\u00e6ti […]<\/em> \u00cd fyrsta lagi neitum v\u00e9r \u00feeim ekki um eigin krafta, sem \u00fe\u00e6r senda fr\u00e1 s\u00e9r me\u00f0 \u00fatstreymi s\u00ednu. A\u00f0 [kraftarnir]<\/em> s\u00e9u l\u00edka breytilegir eftir samsetningu hverrar stj\u00f6rnu, grunar oss r\u00e9ttilega af mismunandi lit stjarnanna, en skilst \u00fea\u00f0 af \u00e1hrifunum og segjum a\u00f0 \u00feeir berist sumpart af m\u00e6tti eigin geisla, en sumpart af v\u00f6ldum s\u00f3larinnar, sem sendir okkur aftur geisla s\u00edna, sem endurkastast af [stj\u00f6rnunum]<\/em>, gagns\u00fdr\u00f0ar af \u00fdmis konar eigindum \u00feeirra. En a\u00f0 \u00fev\u00ed s\u00f6g\u00f0u er \u00fev\u00ed vi\u00f0 a\u00f0 b\u00e6ta, a\u00f0 eiginleika einstakra stjarna h\u00f6fum v\u00e9r ekki fullkanna\u00f0 n\u00e9 mun nokkurn t\u00edmann ver\u00f0a h\u00e6gt a\u00f0 kanna \u00fe\u00e1.<\/p><\/blockquote>\n

G\u00edsli var undir talsver\u00f0um \u00e1hrifum fr\u00e1 kennara s\u00ednum, J. From<\/a>, sem t\u00f3k vi\u00f0 af Longomontanusi<\/a> sem pr\u00f3fessor \u00ed stj\u00f6rnufr\u00e6\u00f0i vi\u00f0 Hafnarh\u00e1sk\u00f3la \u00e1ri\u00f0 1647. \u00c1 s\u00ednum t\u00edma \u00fe\u00f3tti Longomontanus einstaklega \u00edhaldssamur, en \u00fea\u00f0 vi\u00f0horf um tilgang stj\u00f6rnufr\u00e6\u00f0innar, sem hann setur fram \u00ed kaflanum De tubo optico \u00ed lok b\u00f3kar sinnar Introductio in theatrum astronomicum<\/a> fr\u00e1 1639, m\u00e1 einnig sj\u00e1 \u00ed verkum margra \u00feekktra stj\u00f6rnufr\u00e6\u00f0inga n\u00e6stu tv\u00e6r aldirnar. \u00cd kaflanum segir (lauslega \u00fe\u00fdtt og endursagt):<\/p>\n

Vi\u00f0fangsefni stj\u00f6rnufr\u00e6\u00f0innar sn\u00fdst ekki um ranns\u00f3knir \u00e1 stj\u00f6rnunum sj\u00e1lfum og eiginleikum \u00feeirra, heldur (s\u00fdndar)hreyfingum \u00feeirra og umfer\u00f0art\u00edma. Stj\u00f6rnufr\u00e6\u00f0in l\u00e6tur n\u00e1tt\u00faruspekinni \u00fea\u00f0 eftir a\u00f0 kanna eiginleika stjarnanna, sem h\u00fan og gerir me\u00f0 a\u00f0sto\u00f0 lj\u00f3sfr\u00e6\u00f0innar.<\/p><\/blockquote>\n

Hinn fr\u00e6gi danski stj\u00f6rnufr\u00e6\u00f0ingur, O. R\u00f6mer<\/a>, mun hafa haft svipa\u00f0ar sko\u00f0anir. Til er eftir hann latneskt handrit fr\u00e1 lokum sautj\u00e1ndu aldar, sem me\u00f0al annars fjallar um tilraunir hans, \u00e1rin 1692 og 1693, til a\u00f0 \u00e1kvar\u00f0a \u00e1rlega hli\u00f0run fastastjarnanna S\u00edr\u00edusar og Vegu. \u00c1ri\u00f0 1735 birti P. Horrebow<\/a> handriti\u00f0 \u00ed t\u00edunda kafla ritsins Basis Astronomiae<\/a> (d\u00f6nsk \u00fe\u00fd\u00f0ing hj\u00e1\u00a0 E. Str\u00f6mgren, 1944: Ole R\u00f8mer som Astronom<\/a> (bls. 81-91)). \u00dear minnist R\u00f6mer stuttlega \u00e1 heimsmyndina og segir (\u00a7 142 & 143, bls. 63-64):<\/p>\n

Spurningin um hreyfingu jar\u00f0arinnar kemur stj\u00f6rnufr\u00e6\u00f0inni ekkert s\u00e9rlega miki\u00f0 vi\u00f0, \u00fear sem fr\u00e6\u00f0igreinin sn\u00fdst eing\u00f6ngu um \u00fea\u00f0 a\u00f0 finna og m\u00e6la st\u00f6\u00f0u og hreyfingu allra stjarna, mi\u00f0a\u00f0 vi\u00f0 okkur jar\u00f0arb\u00faa. \u00dea\u00f0 er h\u00e6gt a\u00f0 gera jafn au\u00f0veldlega og \u00f6rugglega, hvort heldur sem gengi\u00f0 er \u00fat fr\u00e1 kenningu Tychos um kyrrst\u00e6\u00f0a j\u00f6r\u00f0 e\u00f0a kenningu K\u00f3ern\u00edkusar um a\u00f0 h\u00fan hreyfist. […]<\/em> \u00de\u00f3tt \u00fea\u00f0 skipti stj\u00f6rnufr\u00e6\u00f0inga engu, hvort j\u00f6r\u00f0in hreyfist \u00e1samt hinum reikistj\u00f6rnunum umhverfis kyrrst\u00e6\u00f0a s\u00f3lina, e\u00f0a hvort s\u00f3lin \u00e1 sinni \u00e1rlegu hreyfingu dragi me\u00f0 s\u00e9r \u00feennan fylgihnattaskara umhverfis j\u00f6r\u00f0ina, \u00fe\u00e1 eru n\u00e1tt\u00faruspekingarnir og \u00feeir sem \u00e1huga hafa \u00e1 heimi n\u00e1tt\u00farunnar, haldnir st\u00f6\u00f0ugri l\u00f6ngun til a\u00f0 \u00f6\u00f0last vitnesku um \u00fea\u00f0, hvora lei\u00f0ina hinn \u00e6\u00f0sti skapari hefur vali\u00f0 fyrir hreyfingu e\u00f0a kyrrst\u00f6\u00f0u \u00feessara himinhnatta.<\/p><\/blockquote>\n

Eins og \u00e1\u00f0ur sag\u00f0i, mun \u00feetta vi\u00f0horf hafa haldist \u00fev\u00ed sem n\u00e6st \u00f3breytt me\u00f0al stj\u00f6rnufr\u00e6\u00f0inga allt fram \u00e1 mi\u00f0ja n\u00edtj\u00e1ndu \u00f6ld. \u00dea\u00f0 m\u00e1 me\u00f0al annars sj\u00e1 \u00e1 eftirfarandi umm\u00e6lum \u00a0F. W. Bessels<\/a> \u00e1ri\u00f0 1848 \u00ed al\u00fe\u00fd\u00f0uritinu Popul\u00e4re Vorlesungen \u00fcber wissenschaftliche Gegenst\u00e4nde<\/a> (bls. 5-6):<\/p>\n

Markmi\u00f0 stj\u00f6rnufr\u00e6\u00f0innar er \u00e1vallt hi\u00f0 sama: H\u00fan setur fram reglur um \u00fea\u00f0, hvernig reikna skuli hreyfingu himinhnattanna, eins og h\u00fan l\u00edtur \u00fat fr\u00e1 j\u00f6r\u00f0inni s\u00e9\u00f0. Allt anna\u00f0 sem l\u00e6ra m\u00e1 um \u00feessi fyrirb\u00e6ri, til d\u00e6mis um \u00fatlit \u00feeirra og eiginleika yfirbor\u00f0anna, m\u00e1 svo sem veita athygli, en sl\u00edkt hefur enga stjarnfr\u00e6\u00f0ilega \u00fe\u00fd\u00f0ingu.<\/p><\/blockquote>\n

\u00c1 n\u00edtj\u00e1ndu \u00f6ldinni l\u00f6g\u00f0u stj\u00f6rnufr\u00e6\u00f0ingar \u00fev\u00ed megin\u00e1herslu \u00e1 \u00fea\u00f0 a\u00f0 reikna brautir himinhnatta me\u00f0 s\u00edvaxandi n\u00e1kv\u00e6mni. Jafnframt var mikil vinna l\u00f6g\u00f0 \u00ed \u00fer\u00f3un og sm\u00ed\u00f0i n\u00fdrra sj\u00f3nauka, ekki s\u00edst linsusj\u00f3nauka<\/a>, einkum til \u00feess a\u00f0 geta framkv\u00e6mt sem n\u00e1kv\u00e6mastar sta\u00f0ar- og t\u00edmam\u00e6lingar.<\/p>\n

Eins og fram kom \u00ed fyrri f\u00e6rslu<\/a>, bar \u00feessi fastm\u00f3ta\u00f0a a\u00f0fer\u00f0afr\u00e6\u00f0i r\u00edkulegan \u00e1v\u00f6xt. H\u00fan ger\u00f0i \u00fea\u00f0 me\u00f0al annars a\u00f0 verkum, a\u00f0 \u00e1ri\u00f0 1838 t\u00f3kst \u00ed fyrsta sinn a\u00f0 m\u00e6la \u00e1rlega hli\u00f0run<\/a> n\u00e1l\u00e6gra fastastjarna og leggja \u00feannig grunn a\u00f0 n\u00e1kv\u00e6mri kortlagingu stj\u00f6rnudreifingar \u00ed n\u00e6sta n\u00e1grenni s\u00f3lkerfisins. \u00de\u00e1 er r\u00e9tt a\u00f0 minna \u00e1 fund Nept\u00fanusar<\/a> \u00e1ri\u00f0 1846, en \u00fear a\u00f0 baki er mikil og merkileg saga.<\/p>\n