{"id":13581,"date":"2019-11-19T22:28:10","date_gmt":"2019-11-19T22:28:10","guid":{"rendered":"http:\/\/uni.hi.is\/einar\/?p=13581"},"modified":"2019-11-19T22:28:10","modified_gmt":"2019-11-19T22:28:10","slug":"afstaediskenningar-einsteins-og-grein-thorkels-thorkelssonar-um-tilraunir-til-ad-sannreyna-thaer","status":"publish","type":"post","link":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/?p=13581","title":{"rendered":"Afst\u00e6\u00f0iskenningar Einsteins og grein \u00deorkels \u00deorkelssonar um tilraunir til a\u00f0 sannreyna \u00fe\u00e6r"},"content":{"rendered":"<p>\u00deetta yfirlit var upphaflega birt \u00ed j\u00fan\u00ed 2019 sem hluti af f\u00e6rslu um <a href=\"http:\/\/uni.hi.is\/einar\/2019\/06\/23\/thorkell-thorkelsson\/\">\u00deorkel \u00deorkelsson e\u00f0lisfr\u00e6\u00f0ing (1876-1961)<\/a>.<\/p>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\"><span style=\"font-size: 14pt\"><strong>Afst\u00e6\u00f0iskenningar Einsteins<\/strong><\/span><\/h3>\n<p style=\"text-align: center\"><span style=\"font-size: 12pt\"><strong>Takmarka\u00f0a kenningin<\/strong><\/span><\/p>\n<p>Einstein birti fyrstu greinar s\u00ednar um <a href=\"https:\/\/en.wikipedia.org\/wiki\/Special_relativity\">takm\u00f6rku\u00f0u afst\u00e6\u00f0iskenninguna<\/a> \u00e1ri\u00f0 1905. \u00dea\u00f0 \u00e1r hefur stundum veri\u00f0 kalla\u00f0 kraftaverka\u00e1ri\u00f0, \u00fev\u00ed auk greinanna um afst\u00e6\u00f0iskenninguna birti hann t\u00edmam\u00f3tagreinar um lj\u00f3sskammta og tilvist at\u00f3ma.<\/p>\n<ul>\n<li>Einar H. Gu\u00f0mundsson, 2005:\u00a0 <a href=\"https:\/\/notendur.hi.is\/~einar\/Afstaediskenning\/Einstein1905.pdf\">Albert Einstein og greinar hans fr\u00e1 1905<\/a>.<\/li>\n<\/ul>\n<p>Svo heppilega vill til, a\u00f0 \u00e1 aldarafm\u00e6li almennu afst\u00e6\u00f0iskenningarinnar \u00e1ri\u00f0 2015 komu allar greinar Einsteins fr\u00e1 1905 \u00fat \u00ed \u00edslenskri \u00fe\u00fd\u00f0ingu \u00e1samt s\u00f6gulegum inngangi og sk\u00fdringum:<\/p>\n<ul>\n<li>\u00deorsteinn Vilhj\u00e1lmsson, ritstj\u00f3ri, 2015: <a href=\"https:\/\/hib.is\/vara\/einstein-eindir-og-afstaedi\/\">Einstein. Eindir og afst\u00e6\u00f0i<\/a>. \u00deri\u00f0ji kafli b\u00f3karinnar fjallar um s\u00f6gulegan a\u00f0draganda afst\u00e6\u00f0iskenningarinnar, en greinar Einsteins sj\u00e1lfs eru \u00e1 s\u00ed\u00f0um 253-284.<\/li>\n<\/ul>\n<p>Eftir a\u00f0 Einstein birti yfirlitsgrein s\u00edna um almennu afst\u00e6\u00f0iskenninguna \u00e1ri\u00f0 1916 t\u00f3k hann sig til og skrifa\u00f0i b\u00e6kling um kenningar s\u00ednar fyrir almenning. Riti\u00f0 kom \u00fat \u00ed \u00de\u00fdskalandi \u00e1ri\u00f0 1916 og er til \u00ed \u00edslenskri \u00fe\u00fd\u00f0ingu:<\/p>\n<ul>\n<li>A. Einstein, 1970: <a href=\"https:\/\/hib.is\/vara\/afstaediskenningin\/\">Afst\u00e6\u00f0iskenningin<\/a>. (N\u00fd og endursko\u00f0u\u00f0 \u00fatg\u00e1fa kom \u00fat 1978.)<\/li>\n<\/ul>\n<p style=\"text-align: center\"><strong>Jafngildisl\u00f6gm\u00e1li\u00f0<\/strong><\/p>\n<p>\u00c1ri\u00f0 1907 t\u00f3k Einstein a\u00f0 huglei\u00f0a, hvernig best v\u00e6ri a\u00f0 l\u00fdsa \u00feyngdinni innan v\u00e9banda takm\u00f6rku\u00f0u afst\u00e6\u00f0iskenningarinnar. \u00dea\u00f0 var\u00f0 til \u00feess, a\u00f0 hann uppg\u00f6tva\u00f0i hi\u00f0 svokalla\u00f0a <a href=\"http:\/\/www.einstein-online.info\/spotlights\/equivalence_principle.html\">jafngildisl\u00f6gm\u00e1l<\/a> (sj\u00e1 <a href=\"https:\/\/einsteinpapers.press.princeton.edu\/vol2-doc\/512\">grein Einsteins<\/a> fr\u00e1 1907, s\u00ed\u00f0ustu m\u00e1lsgreinarnar \u00ed \u00a717), sem reyndist vera fyrsta skrefi\u00f0 \u00ed \u00e1tt a\u00f0 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Introduction_to_general_relativity\">almennu kenningunni<\/a>. L\u00f6gm\u00e1li\u00f0 m\u00e1 or\u00f0a \u00e1 \u00fdmsa vegu, en h\u00e9r hentar best a\u00f0 nota framsetningu \u00fear sem einfaldlega segir, a\u00f0 hr\u00f6\u00f0un og \u00feyngd s\u00e9u jafngild.<\/p>\n<p>Af jafngildisl\u00f6gm\u00e1linu lei\u00f0ir me\u00f0al annars hi\u00f0 svokalla\u00f0a <a href=\"http:\/\/www.einstein-online.info\/spotlights\/redshift_white_dwarfs.html\">\u00feyngdarrau\u00f0vik<\/a> (e\u00f0a \u00feyngdarbl\u00e1vik, eftir a\u00f0st\u00e6\u00f0um; sj\u00e1 <a href=\"https:\/\/einsteinpapers.press.princeton.edu\/vol2-doc\/512\">grein Einsteins<\/a>, \u00a719) og einnig, a\u00f0 <a href=\"http:\/\/www.einstein-online.info\/spotlights\/light_deflection.html\">lj\u00f3s fer\u00f0ast eftir sveig\u00f0um brautum<\/a> \u00ed \u00feyngdarsvi\u00f0i (<a href=\"https:\/\/einsteinpapers.press.princeton.edu\/vol2-doc\/512\">grein Einsteins<\/a>, ne\u00f0arlega \u00e1 bls. 483). L\u00f6gm\u00e1li\u00f0 eitt n\u00e6gir til a\u00f0 reikna \u00feyngdarrau\u00f0viki\u00f0, en a\u00f0eins helming lj\u00f3ssveigjunnar. Hinn helmingurinn stafar af sveigju r\u00famsins, eins og \u00ed lj\u00f3s kom \u00ed \u00e1rslok 1915.<\/p>\n<p>\u00c1ri\u00f0 1911 birti Einstein greinina <a href=\"https:\/\/einsteinpapers.press.princeton.edu\/vol3-doc\/524\">\u00dcber den Einflu\u00df der Schwerkraft auf die Ausbreitung des Lichtes<\/a>. \u00dear gerir hann a\u00f0ra tilraun til a\u00f0 leggja grunn a\u00f0 n\u00fdrri kenningu um \u00feyngdina. Hann notar jafngildisl\u00f6gm\u00e1li\u00f0 til a\u00f0 finna b\u00e6\u00f0i \u00feyngdarrau\u00f0vik <a href=\"https:\/\/en.wikipedia.org\/wiki\/Fraunhofer_lines\">Fraunhofer-l\u00ednanna<\/a> \u00ed litr\u00f3fi s\u00f3larinnar og sveigjuhorn lj\u00f3sgeisla fr\u00e1 fjarl\u00e6gri stj\u00f6rnu, sem r\u00e9tt sleikir s\u00f3laryfirbor\u00f0i\u00f0. Fyrir rau\u00f0viki\u00f0 f\u00e6r hann, a\u00f0 t\u00ed\u00f0ni lj\u00f3ss minnki um 0,0002% \u00e1 lei\u00f0 fr\u00e1 s\u00f3linni til jar\u00f0ar (bls. 493), sem er r\u00e9tt ni\u00f0ursta\u00f0a. Fyrir sveigjuhorni\u00f0 f\u00e6r hann hins vegar 0,83 bogasek\u00fandur (bls. 496), sem er helmingi of l\u00edti\u00f0, eins og \u00e1\u00f0ur sag\u00f0i. R\u00e9ttu ni\u00f0urst\u00f6\u00f0una, 1, 75 bogasek\u00fandur fann hann ekki fyrr en \u00ed n\u00f3vember 1915.<\/p>\n<p>Eftir a\u00f0 greinin fr\u00e1 1911 kom \u00fat, reyndi Einstein a\u00f0 vekja athygli stj\u00f6rnufr\u00e6\u00f0inga \u00e1 ni\u00f0urst\u00f6\u00f0um s\u00ednum \u00ed \u00feeirri von, a\u00f0 einhver \u00feeirra t\u00e6ki sig til og reyndi a\u00f0 sannreyna \u00fe\u00e6r me\u00f0 m\u00e6lingum.\u00a0 Me\u00f0al annars haf\u00f0i hann samband vi\u00f0 bandar\u00edska stj\u00f6rnufr\u00e6\u00f0inginn <a href=\"https:\/\/en.wikipedia.org\/wiki\/George_Ellery_Hale\">G. E. Hale<\/a> af \u00feessu tilefni hausti\u00f0 1913, en \u00e1n \u00e1rangurs.<\/p>\n<div id=\"attachment_9630\" class=\"wp-caption aligncenter\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-9630\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/04\/EINSTEIN-LETTER-1913-Letter-to-Hale--300x81.png\" alt=\"\" width=\"530\" height=\"143\" aria-describedby=\"caption-attachment-9630\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/04\/EINSTEIN-LETTER-1913-Letter-to-Hale--300x81.png 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/04\/EINSTEIN-LETTER-1913-Letter-to-Hale-.png 744w\" sizes=\"auto, (max-width: 530px) 100vw, 530px\" \/><\/p>\n<p id=\"caption-attachment-9630\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">\u00d6nnur af tveimur teikningum Einsteins <a href=\"https:\/\/physicstoday.scitation.org\/doi\/pdf\/10.1063\/1.2117798\">\u00ed br\u00e9fi<\/a> til G. E. Hales hausti\u00f0 1913. \u00dear \u00fatsk\u00fdrir hann lj\u00f3ssveigjuna vi\u00f0 r\u00f6nd s\u00f3lar og spyr, hversu n\u00e1l\u00e6gt s\u00f3linni megi sj\u00e1 fastastj\u00f6rnur \u00ed dagslj\u00f3si me\u00f0 n\u00fdjustu og bestu t\u00e6kni.<\/span><\/p>\n<\/div>\n<p>Fyrsti stj\u00f6rnufr\u00e6\u00f0ingurinn, sem br\u00e1st j\u00e1kv\u00e6tt vi\u00f0 bei\u00f0ni Einsteins, var <a href=\"https:\/\/en.wikipedia.org\/wiki\/Erwin_Finlay-Freundlich\">Erwin Finley Freundlich<\/a>. Hann ger\u00f0i \u00edtreka\u00f0ar tilraunir til a\u00f0 m\u00e6la lj\u00f3ssveigjuna vi\u00f0 s\u00f3lmyrkva og einnig a\u00f0 \u00e1kvar\u00f0a \u00feyngdarrau\u00f0viki\u00f0 \u00ed lj\u00f3si s\u00f3lar og annarra stjarna. Freundlich var hins vegar me\u00f0 eind\u00e6mum \u00f3heppinn og allar tilraunir hans til a\u00f0 sta\u00f0festa \u00fatreikninga Einsteins misheppnu\u00f0ust. Um \u00fe\u00e1 s\u00f6gu m\u00e1 lesa n\u00e1nar <a href=\"https:\/\/pdfs.semanticscholar.org\/1473\/4fecc56911e0beac7a45ff80dbe3e7d19890.pdf\">h\u00e9r<\/a>. \u00ddmsir a\u00f0rir stj\u00f6rnufr\u00e6\u00f0ingar, sem s\u00ed\u00f0ar komu a\u00f0 samskonar m\u00e6lingum, lentu \u00ed svipu\u00f0um vandr\u00e6\u00f0um, enda valda margv\u00edslegar \u00e1st\u00e6\u00f0ur \u00fev\u00ed, a\u00f0 m\u00e6lingarnar eru einstaklega erfi\u00f0ar.<\/p>\n<p>\u00deegar liti\u00f0 er til baka m\u00e1 segja, a\u00f0 \u00fea\u00f0 hafi veri\u00f0 l\u00e1n Einsteins, a\u00f0 \u00feessar fyrstu m\u00e6lingar skyldu mistakast. N\u00e1kv\u00e6mar m\u00e6lingar hef\u00f0u nefnilega s\u00fdnt, a\u00f0 lj\u00f3ssveigjan nam tv\u00f6faldri ni\u00f0urst\u00f6\u00f0u hans fr\u00e1 1911.<\/p>\n<p>Leit Einsteins a\u00f0 almennu afst\u00e6\u00f0iskenningunni lauk ekki a\u00f0 fullu fyrr en \u00ed n\u00f3vember 1915 og handriti\u00f0 a\u00f0 yfirlistsgrein hans, <a href=\"http:\/\/myweb.rz.uni-augsburg.de\/~eckern\/adp\/history\/einstein-papers\/1916_49_769-822.pdf\">Die Grundlage der allgemeinen Relativit\u00e4tstheorie<\/a>, var ekki tilb\u00fai\u00f0 fyrr en \u00ed mars 1916.<\/p>\n<p style=\"text-align: center\"><strong>Almenna kenningin<\/strong><\/p>\n<p>\u00cd lok hinnar m\u00f6gnu\u00f0u <a href=\"http:\/\/myweb.rz.uni-augsburg.de\/~eckern\/adp\/history\/einstein-papers\/1916_49_769-822.pdf\">yfirlitsgreinar<\/a> fr\u00e1 1916 bendir Einstein \u00e1 \u00ferj\u00e1r lei\u00f0ir til a\u00f0 sannreyna kenninguna. Hina fyrstu, sk\u00fdringu \u00e1 \u00e1kve\u00f0nu misr\u00e6mi \u00ed s\u00edgildum \u00fatreikningum og m\u00e6lingum \u00e1 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Tests_of_general_relativity#Perihelion_precession_of_Mercury\">s\u00f3ln\u00e1nd Merk\u00far\u00edusar<\/a>, setti hann reyndar fram sj\u00e1lfur \u00ed greininni (bls. 822). Einnig stakk hann upp \u00e1 \u00fev\u00ed, a\u00f0 stj\u00f6rnufr\u00e6\u00f0ingar reyndu a\u00f0 m\u00e6la \u00feyngdarrau\u00f0viki\u00f0 \u00ed litr\u00f3fi s\u00f3lsjarna (bls. 820) og \u00ed \u00feri\u00f0ja lagi, a\u00f0 \u00feeir m\u00e6ldu lj\u00f3ssveigjuna vi\u00f0 ja\u00f0ar s\u00f3lkringlunnar (bls. 821-22).<\/p>\n<div id=\"attachment_9801\" class=\"wp-caption aligncenter\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-9801\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/05\/Einstein1919-225x300.jpg\" alt=\"\" width=\"331\" height=\"442\" aria-describedby=\"caption-attachment-9801\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/05\/Einstein1919-225x300.jpg 225w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/05\/Einstein1919.jpg 450w\" sizes=\"auto, (max-width: 331px) 100vw, 331px\" \/><\/p>\n<p id=\"caption-attachment-9801\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Einstein \u00ed desember 1919, um \u00fea\u00f0 leyti sem <a href=\"https:\/\/notendur.hi.is\/~einar\/Afstaediskenning\/Myrkvi1919.pdf\">hann var\u00f0 heimsfr\u00e6gur<\/a>.<\/span><\/p>\n<\/div>\n<p>\u00c1\u00f0ur en lengra er haldi\u00f0 m\u00e1 nefna, a\u00f0 afst\u00e6\u00f0iskenning Einsteins fr\u00e1 1915 hefur reynst sannsp\u00e1 um ni\u00f0urst\u00f6\u00f0ur allra vanda\u00f0ra m\u00e6linga, sem ger\u00f0ar hafa veri\u00f0 til a\u00f0 sannreyna hana. \u00c1 hverju andartaki er h\u00fan sta\u00f0fest me\u00f0 fars\u00e6lli notkun <a href=\"http:\/\/www.astronomy.ohio-state.edu\/~pogge\/Ast162\/Unit5\/gps.html\">GPS-t\u00e6kninnar<\/a>, sem v\u00e6ri \u00f3noth\u00e6f, ef \u00fear v\u00e6ri ekki teki\u00f0 fullt tillit til kenninga Einsteins um t\u00edma, r\u00fam og \u00feyngd. \u00c1n afst\u00e6\u00f0iskenningarinnar hef\u00f0i einnig veri\u00f0 illm\u00f6gulegt a\u00f0 skilja eiginleika mikils fj\u00f6lda n\u00fdrra fyrirb\u00e6ra, sem fundist hafa \u00ed geimnum \u00e1 undanf\u00f6rnum sext\u00edu \u00e1rum e\u00f0a svo (til d\u00e6mis <a href=\"https:\/\/en.wikipedia.org\/wiki\/Black_hole\">svarthola<\/a>, <a href=\"https:\/\/en.wikipedia.org\/wiki\/Gravitational_lens\">\u00feyngdarlinsa<\/a> og <a href=\"https:\/\/en.wikipedia.org\/wiki\/Gravitational_wave\">\u00feyngdarbylgna<\/a>). \u00de\u00e1 m\u00e1 minna \u00e1, a\u00f0 kenningin myndar hinn fr\u00e6\u00f0ilega grunn a\u00f0 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Big_Bang\">heimsmynd n\u00fat\u00edma stjarnv\u00edsinda<\/a>.<\/p>\n<p>\u00c1g\u00e6tis yfirlit um \u00fea\u00f0, hvernig afst\u00e6\u00f0iskenningin hefur sta\u00f0ist t\u00edmans t\u00f6nn, m\u00e1 me\u00f0al annars finna \u00ed eftirfarandi ritverkum:<\/p>\n<ul>\n<li>C. M. Will, 2017: <a href=\"https:\/\/www.amphilsoc.org\/sites\/default\/files\/2017-07\/attachments\/Will.pdf\">Did Einstein get it right? A Centennial Assessment.<\/a><\/li>\n<li>C. M. Will, 2014: <a href=\"https:\/\/link.springer.com\/article\/10.12942\/lrr-2014-4\">The Confrontation between General Relativity and Experiment<\/a> (t\u00e6knileg grein).<\/li>\n<li>Wikipedia: <a href=\"https:\/\/en.wikipedia.org\/wiki\/Tests_of_general_relativity\">Tests of General Relativity<\/a>.<\/li>\n<li>J. Crelinsten, 2006: <a href=\"https:\/\/books.google.is\/books?id=W1Dt15vWYGQC&amp;source=gbs_navlinks_s\">Einstein&#8217;s Jury: The Race to Test Relativity<\/a>.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\"><strong><span style=\"font-size: 14pt\">Afst\u00e6\u00f0iskenningin \u00e1 \u00cdslandi 1913-1930<\/span><br \/>\n<\/strong><\/h3>\n<p>\u00d3lafur Dan Dan\u00edelsson var\u00f0 fyrstur \u00cdslendinga til a\u00f0 fjalla um afst\u00e6\u00f0iskenninguna \u00ed ritu\u00f0u m\u00e1li. \u00dea\u00f0 var \u00ed greininni <a href=\"http:\/\/timarit.is\/view_page_init.jsp?gegnirId=000560274\">\u00ddmsar sko\u00f0anir \u00e1 e\u00f0li r\u00famsins<\/a>, sem birtist \u00ed Sk\u00edrni \u00e1ri\u00f0 1913. Greinin vir\u00f0ist hafa vaki\u00f0 litla athygli, \u00feegar h\u00fan kom \u00fat, enda efni\u00f0 mj\u00f6g framandi fyrir flesta lesendur. Ekki er heldur a\u00f0 sj\u00e1, a\u00f0 afst\u00e6\u00f0iskenningin hafi komi\u00f0 aftur til umr\u00e6\u00f0u h\u00e9r \u00e1 landi fyrr en sex \u00e1rum s\u00ed\u00f0ar.<\/p>\n<p>Eftirfarandi yfirlit um fyrstu vi\u00f0br\u00f6g\u00f0 \u00cdslendinga vi\u00f0 afst\u00e6\u00f0iskenningunni er a\u00f0 hluta byggt \u00e1 mun \u00edtarlegri umfj\u00f6llun \u00ed eftirfarandi ritsm\u00ed\u00f0um:<\/p>\n<ul>\n<li>Einar H. Gu\u00f0mundsson og Sk\u00fali Sigur\u00f0sson, 2005: <a href=\"http:\/\/wayback.vefsafn.is\/wayback\/20200221162858\/http:\/\/www.raust.is\/2005\/1\/02\/\">E\u00f0li r\u00fams og t\u00edma: \u00d3lafur Dan Dan\u00edelsson og greinar hans um afst\u00e6\u00f0iskenninguna<\/a>.<\/li>\n<li>Einar H. Gu\u00f0mundsson, 2015: <a href=\"https:\/\/notendur.hi.is\/~einar\/Afstaediskenning\/Myrkvi1919.pdf\">S\u00f3lmyrkvinn sem skaut Einstein upp \u00e1 stj\u00f6rnuhimininn<\/a>.<\/li>\n<\/ul>\n<p>Eins og \u00e1\u00f0ur hefur komi\u00f0 fram, kvikna\u00f0i \u00e1hugi hins almenna \u00cdslendings \u00e1 Einstein og kenningum hans vi\u00f0 fr\u00e9ttir af <a href=\"https:\/\/uni.hi.is\/einar\/2019\/05\/30\/old-lidin-fra-solmyrkvanum-mikla-1919\/\">s\u00f3lmyrkvam\u00e6lingum fr\u00e6gu \u00e1ri\u00f0 1919<\/a>. Fr\u00e9ttin birtist fyrst \u00ed <em>V\u00edsi,<\/em> en svo \u00ed \u00f6\u00f0rum h\u00e9rlendum bl\u00f6\u00f0um \u00e1 n\u00e6stu d\u00f6gum.<\/p>\n<div id=\"attachment_9632\" class=\"wp-caption aligncenter\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-9632\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/04\/Simskeyti-copy.jpg\" alt=\"\" width=\"353\" height=\"309\" aria-describedby=\"caption-attachment-9632\" \/><\/p>\n<p id=\"caption-attachment-9632\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Fyrsta \u00edslenska fr\u00e9ttin um\u00a0 s\u00f3lmyrkvam\u00e6lingarnar birtist \u00ed <em>V\u00edsi<\/em>, 19. n\u00f3vember 1919, bls. 2.<\/span><\/p>\n<\/div>\n<p>Frekari sk\u00fdringar fengust \u00fe\u00f3 ekki fyrr en 5. desember, \u00feegar <em>Morgunbla\u00f0i\u00f0<\/em> birti greinina<a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=1204870\"> Byltingar \u00ed heimi v\u00edsindanna<\/a>. \u00cd greininni, sem er endurs\u00f6gn \u00e1 grein \u00far danska dagbla\u00f0inu <em>Politiken<\/em> fr\u00e1 18. n\u00f3vember (sem aftur bygg\u00f0i umfj\u00f6llun s\u00edna \u00e1 greinum \u00far breska bla\u00f0inu <em>London Times<\/em>), segir me\u00f0al annars:<\/p>\n<blockquote><p>\u00de\u00f3 hefir s\u00fa sta\u00f0h\u00e6fing Einsteins vaki\u00f0 mesta athygli a\u00f0 h\u00e6gt er a\u00f0 vega s\u00f3larlj\u00f3si\u00f0. En \u00fe\u00f3 hefir \u00fea\u00f0 veri\u00f0 sanna\u00f0 me\u00f0al annars af tveimur stj\u00f6rnufr\u00e6\u00f0is ranns\u00f3knarnefndum sem athugu\u00f0u s\u00f3lmyrkvan 29.ma\u00ed sl. \u00e1r, b\u00e6\u00f0i \u00ed Nor\u00f0ur-Brasiliu og \u00e1 vesturstr\u00f6nd Afr\u00edku. Kenningar e\u00f0a uppg\u00f6tvanir Einsteins bentu \u00e1 \u00fea\u00f0, a\u00f0 hreyfing reykistjarnanna v\u00e6ri d\u00e1l\u00edti\u00f0 fr\u00e1brug\u00f0in \u00fev\u00ed, sem Newton h\u00e9lt fram. \u00deetta var sanna\u00f0 hva\u00f0 braut Merk\u00fars snerti. En \u00fea\u00f0 veittist \u00f6r\u00f0ugt a\u00f0 sanna, a\u00f0 lj\u00f3si\u00f0 fylgdi \u00f6\u00f0rum reglum en \u00feeim sem Newton haf\u00f0i fundi\u00f0. En me\u00f0an \u00e1 s\u00f3lmyrkvanum st\u00f3\u00f0, lj\u00f3smyndu\u00f0u menn margar \u00fe\u00e6r stj\u00f6rnur, sem senda lj\u00f3s sitt mj\u00f6g n\u00e6rri s\u00f3linni til jar\u00f0arinnar. \u00de\u00e1 kom \u00fea\u00f0 \u00ed lj\u00f3s, a\u00f0 geislar \u00feesara stjarna, sveig\u00f0ust miki\u00f0 a\u00f0 s\u00f3linni um lei\u00f0 og \u00feeir f\u00f3ru fram hj\u00e1 henni, vegna a\u00f0dr\u00e1ttarafls hennar. \u00deyngdarl\u00f6gm\u00e1l Newtons og yfirh\u00f6fu\u00f0 allar kenningar hans raskast t\u00f6luvert vi\u00f0 \u00feetta.<\/p><\/blockquote>\n<p>Fyrsta riti\u00f0 um kenningar Einsteins, sem kom \u00ed \u00edslenskar b\u00f3kab\u00fa\u00f0ir, var b\u00f3kin <em>Vort fysiske Verdensbillede og Einsteins Relativitetsteori<\/em> eftir danska e\u00f0lisfr\u00e6\u00f0inginn <a href=\"https:\/\/sv.wikipedia.org\/wiki\/Helge_Holst\">Helge Holst<\/a>.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-10174 aligncenter\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/05\/Holst_19209-213x300.png\" alt=\"\" width=\"323\" height=\"455\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/05\/Holst_19209-213x300.png 213w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/05\/Holst_19209-728x1024.png 728w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/05\/Holst_19209-768x1080.png 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/05\/Holst_19209-1092x1536.png 1092w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/05\/Holst_19209-1456x2048.png 1456w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/05\/Holst_19209.png 1677w\" sizes=\"auto, (max-width: 323px) 100vw, 323px\" \/><\/p>\n<p>\u00cd augl\u00fdsingu fr\u00e1 B\u00f3kaverslun \u00c1rs\u00e6ls \u00c1rnasonar \u00ed T\u00edmanum 28. \u00e1g\u00fast 1920 segir svo um riti\u00f0:<\/p>\n<blockquote><p>Margur rak upp st\u00f3r augu er hinga\u00f0 barst fr\u00e9ttin um a\u00f0 \u00dej\u00f3\u00f0verjinn Einstein hef\u00f0i s\u00fdnt fram \u00e1 a\u00f0 kenningar Newtons, sem \u00f6ll e\u00f0lisfr\u00e6\u00f0i haf\u00f0i hinga\u00f0 til veri\u00f0 byg\u00f0 \u00e1, v\u00e6ru rangar. \u00deetta er al\u00fe\u00fd\u00f0lega skrifu\u00f0 b\u00f3k um \u00feessa merkilegu n\u00fdjung; hefir \u00feegar selst afarmiki\u00f0 h\u00e9r \u00ed Reykjav\u00edk.<\/p><\/blockquote>\n<p>\u00deetta mun vera nokku\u00f0 g\u00f3\u00f0 l\u00fdsing \u00e1 vins\u00e6ldum b\u00f3karinnar, \u00fev\u00ed hinn 28. okt\u00f3ber fjallar Al\u00fe\u00fd\u00f0ubla\u00f0i\u00f0 um sama efni \u00e1 fors\u00ed\u00f0u:<\/p>\n<blockquote><p>Menn r\u00e1ku upp st\u00f3r augu \u00ed fyrra vetur er s\u00fa fregn flaug eins og eldur \u00ed sinu um allan menta\u00f0an heim a\u00f0 Gy\u00f0ingurinn Einstein hef\u00f0i gert uppg\u00f6tvanir sem umturnu\u00f0u \u00feyngdarl\u00f6gm\u00e1li Newtons, sem s\u00ed\u00f0an 168<em>[7]<\/em> haf\u00f0i veri\u00f0 eini hyrningarsteinn e\u00f0lisfr\u00e6\u00f0innar. Erlendis var um sinn varla um anna\u00f0 tala\u00f0 en \u00feessa merkilegu uppg\u00f6tvun <em>[&#8230;]\u00a0<\/em> \u00c1 \u00cdslandi var hlj\u00f3\u00f0ast um \u00feetta, enda voru \u00feeir v\u00edst teljandi er svo v\u00e6ri lj\u00f3st hva\u00f0 h\u00e9r hef\u00f0i gerst a\u00f0 \u00feeir g\u00e6tu sk\u00fdrt efni\u00f0 fyrir \u00f6\u00f0rum, \u00fe\u00f3 mun eigi hafa skort \u00e1hugan h\u00e9r, eins og bezt kom \u00ed lj\u00f3s \u00e1 s\u00ed\u00f0astli\u00f0nu sumri er hin \u00e1g\u00e6ta al\u00fe\u00fd\u00f0ub\u00f3k <em>[Holsts]<\/em> kom hinga\u00f0, \u00fev\u00ed \u00fe\u00f3tt b\u00f3kaverslum Gyldendal sendi \u00e1litlegan for\u00f0a <em>[til \u00c1rs\u00e6ls]<\/em> er m\u00e6lt a\u00f0 hann \u00fe\u00f3 eftir f\u00e1a daga hafi or\u00f0i\u00f0 a\u00f0 s\u00edma eftir vi\u00f0b\u00f3t. Og enn\u00fe\u00e1 selst kveri\u00f0 meira en flestar a\u00f0rar erlendar b\u00e6kur.<\/p><\/blockquote>\n<p>\u00c1 n\u00e6stu \u00e1rum var talsvert rita\u00f0 um Einstein, pers\u00f3nu hans og athafnir \u00ed \u00edslenskum bl\u00f6\u00f0um. Fjalla\u00f0 var um sko\u00f0anir hans \u00e1 flestu milli himins og jar\u00f0ar, ekki s\u00edst \u00e1 \u00fej\u00f3\u00f0f\u00e9lags- og tr\u00fam\u00e1lum. \u00de\u00e1 var geti\u00f0 um andst\u00f6\u00f0una, sem kenningar hans s\u00e6ttu, einkum \u00ed \u00de\u00fdskalandi.<\/p>\n<p>Ekki m\u00e1 heldur gleyma tilraunum til a\u00f0 \u00fatsk\u00fdra hugmyndir Einsteins \u00e1 al\u00fe\u00fd\u00f0legan h\u00e1tt. \u00dear var einna fremstur \u00ed flokki heimspekingurinn \u00c1g\u00fast H. Bjarnason, eins og sj\u00e1 m\u00e1 \u00e1 eftirfarandi lista um sl\u00edk fr\u00e6\u00f0slurit fr\u00e1 \u00e1runum 1921-31:<\/p>\n<ul>\n<li>J. Holtsmark, 1921: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?gegnirId=000537398\">Einsteinskenning<\/a>. (\u00de\u00fd\u00f0anda er ekki geti\u00f0.)<\/li>\n<li>A. Moszkowski, 1921-22: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?gegnirId=000665819\">Einstein<\/a>. (\u00de\u00fd\u00f0andi: \u00c1g\u00fast H. Bjarnason.)<\/li>\n<li>\u00c1g\u00fast H. Bjarnason, 1926: <em>Himingeimurinn<\/em> (bls.184-188).<\/li>\n<li>\u00c1g\u00fast H. Bjarnason, 1931: <em>Heimsmynd v\u00edsindanna<\/em> (bls. 7-35).<\/li>\n<\/ul>\n<p>Af tv\u00edeykinu \u00d3lafi Dan og \u00deorkeli, var \u00fea\u00f0 fyrst og fremst \u00d3lafur, sem l\u00e9t til s\u00edn taka \u00e1 \u00feessu svi\u00f0i. Fyrir utan greinina fr\u00e1 1913, sem \u00e1\u00f0ur var geti\u00f0, gaf hann \u00fat tv\u00e6r fr\u00e6\u00f0slugreinar um kenningar Einsteins, a\u00f0ra t\u00e6knilega um takm\u00f6rku\u00f0u kenninguna 1921, hina al\u00fe\u00fd\u00f0lega \u00e1ri\u00f0 1922. \u00dear er b\u00e6\u00f0i fjalla\u00f0 um takm\u00f6rku\u00f0u og almennu afst\u00e6\u00f0iskenninguna.<\/p>\n<ul>\n<li>\u00d3lafur Dan Dan\u00edelsson, 1921:\u00a0 <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=5436134\">Um t\u00edmar\u00fam Minkowskis \u00ed samband\u00ed v\u00ed\u00f0 afst\u00e6\u00f0iskenninguna \u00ferengri<\/a> (t\u00e6knileg grein).<\/li>\n<li>\u00d3lafur Dan Dan\u00edelsson, 1922: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?gegnirId=000560271\">Afst\u00e6\u00f0iskenningin<\/a>.<\/li>\n<\/ul>\n<p>Allar \u00ferj\u00e1r ritsm\u00ed\u00f0ar \u00d3lafs um afst\u00e6\u00f0iskenninguna eru teknar til \u00edtarlegrar sko\u00f0unar \u00ed eftirfarandi grein, og ver\u00f0ur l\u00e1ti\u00f0 n\u00e6gja a\u00f0 v\u00edsa til hennar h\u00e9r:<\/p>\n<ul>\n<li>Einar H. Gu\u00f0mundsson og Sk\u00fali Sigur\u00f0sson, 2005: <a href=\"http:\/\/wayback.vefsafn.is\/wayback\/20200221162858\/http:\/\/www.raust.is\/2005\/1\/02\/\">E\u00f0li r\u00fams og t\u00edma: \u00d3lafur Dan Dan\u00edelsson og greinar hans um afst\u00e6\u00f0iskenninguna<\/a>.<\/li>\n<\/ul>\n<p>\u00de\u00e1 er l\u00edti\u00f0 anna\u00f0 eftir, en r\u00e6\u00f0a grein \u00deorkels \u00deorkelssonar fr\u00e1 1926 um erlendar tilraunir til a\u00f0 sannreyna afst\u00e6\u00f0iskenninguna. \u00dea\u00f0 ver\u00f0ur gert \u00ed n\u00e6sta og jafnframt s\u00ed\u00f0asta kafla f\u00e6rslunnar.<\/p>\n<p>Segja m\u00e1, a\u00f0 um og upp\u00far 1930 hafi meirihluti e\u00f0lisv\u00edsindamanna veri\u00f0 farinn a\u00f0 l\u00edta \u00e1 afst\u00e6\u00f0iskenninguna sem hina vi\u00f0teknu kenningu um r\u00fam, t\u00edma og \u00feyngd. \u00dea\u00f0 hentar \u00fev\u00ed \u00e1g\u00e6tlega a\u00f0 hafa kaflaskil \u00ed s\u00f6gunni um \u00fea\u00f0 leyti. Um framhaldi\u00f0 er \u00fea\u00f0 a\u00f0 segja, a\u00f0 \u00ed komandi f\u00e6rslu er \u00e6tlunin a\u00f0 gefa stutt yfirlit yfir kynni \u00cdslendinga af stjarne\u00f0lisfr\u00e6\u00f0i og heimsfr\u00e6\u00f0i \u00e1 \u00e1runum 1850 til 1960. \u00c1 seinni hluta \u00feess t\u00edmabils kemur afst\u00e6\u00f0iskenningin talsvert vi\u00f0 s\u00f6gu. \u00cd kj\u00f6lfari\u00f0 ver\u00f0ur svo t\u00edmabili\u00f0 eftir 1960 teki\u00f0 fyrir, me\u00f0 megin\u00e1herslu \u00e1 ranns\u00f3knir \u00ed afst\u00e6\u00f0ilegri stjarne\u00f0lisfr\u00e6\u00f0i vi\u00f0 H\u00e1sk\u00f3la \u00cdslands.<\/p>\n<p>&nbsp;<\/p>\n<h3 style=\"text-align: center\"><strong><span style=\"font-size: 14pt\">Grein \u00deorkels um sta\u00f0festingu afst\u00e6\u00f0iskenningarinnar<\/span><br \/>\n<\/strong><\/h3>\n<p>\u00c1ri\u00f0 1925 var afst\u00e6\u00f0iskenningin talsvert til umr\u00e6\u00f0u \u00ed erlendum bl\u00f6\u00f0um og t\u00edmaritum. \u00c1st\u00e6\u00f0an var s\u00fa, a\u00f0 tveir v\u00edsindamenn \u00ed Bandar\u00edkjunum h\u00f6f\u00f0u birt ni\u00f0urst\u00f6\u00f0ur n\u00fdrra m\u00e6linga er v\u00f6r\u00f0u\u00f0u kenninguna. Annars vegar taldi W. S. Adams sig hafa m\u00e6lt \u00feyngdarrau\u00f0vik \u00ed litr\u00f3fi hv\u00edta dvergsins S\u00edr\u00edusar B, en hins vegar haf\u00f0i D. C. Miller endurteki\u00f0 Michelson-Morley tilraunina og fengi\u00f0 a\u00f0rar ni\u00f0urst\u00f6\u00f0ur en fyrirrennarar hans.<\/p>\n<p>\u00deorkell hefur greinilega tali\u00f0 \u00e1st\u00e6\u00f0u til a\u00f0 segja f\u00e9l\u00f6gum s\u00ednum \u00ed Verkfr\u00e6\u00f0ingaf\u00e9laginu fr\u00e1 \u00feessum n\u00fdju m\u00e6lingum. \u00cd apr\u00edl 1926 h\u00e9lt hann \u00fev\u00ed fyrirlestur \u00ed f\u00e9laginu og birti hann s\u00ed\u00f0an \u00ed riti f\u00e9lagsins:<\/p>\n<ul>\n<li>\u00deorkell \u00deorkelsson, 1926: <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=5439323\"> Afst\u00e6\u00f0iskenningin og tilraun Michelsons<\/a>.<\/li>\n<\/ul>\n<p>Ekki kemur beinl\u00ednis fram \u00ed greininni, hva\u00f0a heimildir \u00deorkell hefur stu\u00f0st vi\u00f0, svo v\u00ed\u00f0a ver\u00f0ur a\u00f0 geta \u00ed ey\u00f0urnar. Hins vegar er athyglisvert, a\u00f0 \u00f3l\u00edkt \u00f6\u00f0rum \u00edslenskum h\u00f6fundum \u00e1 \u00feessum t\u00edma, n\u00e1lgast \u00deorkell vi\u00f0fangsefni\u00f0 \u00e1 gagnr\u00fdnin h\u00e1tt. \u00dea\u00f0 sk\u00edn \u00fe\u00f3 \u00ed gegn, a\u00f0 hann er almennt j\u00e1kv\u00e6\u00f0ur \u00ed gar\u00f0 afst\u00e6\u00f0iskenningarinnar. \u00cd \u00fev\u00ed sambandi m\u00e1 og minna \u00e1, a\u00f0 \u00fe\u00f3tt almenningur hafi \u00feegar veri\u00f0 b\u00fainn a\u00f0 taka Einstein \u00ed gu\u00f0at\u00f6lu \u00e1ri\u00f0 1926, voru \u00fdmsir fr\u00e6\u00f0imenn enn vantr\u00faa\u00f0ir \u00e1 kenningar hans (sj\u00e1 til d\u00e6mis <a href=\"https:\/\/en.wikipedia.org\/wiki\/Criticism_of_the_theory_of_relativity#Claimed_experimental_refutationshttps:\/\/en.wikipedia.org\/wiki\/Tests_of_special_relativity\">h\u00e9r<\/a>).<\/p>\n<p>M\u00e6lini\u00f0urst\u00f6\u00f0urnar, sem \u00deorkell fjallar um, ollu talsver\u00f0um deilum \u00ed h\u00f3pi stjarnv\u00edsindamanna \u00e1 s\u00ednum t\u00edma. Sj\u00e1lfur lag\u00f0i \u00deorkell \u00fe\u00f3 ekkert n\u00fdtt til\u00a0 al\u00fej\u00f3\u00f0legrar umr\u00e6\u00f0u um efni\u00f0 og grein hans hefur eing\u00f6ngu menningars\u00f6gulegt gildi fyrir okkur \u00cdslendinga. Langt er s\u00ed\u00f0an deilum\u00e1lin voru \u00fatklj\u00e1\u00f0, og til \u00feessa hefur afst\u00e6\u00f0iskenning Einsteins sta\u00f0ist \u00f6ll \u00e1hlaup, sem \u00e1 hana hafa veri\u00f0 ger\u00f0 (sj\u00e1 \u00ed \u00feessu sambandi heimildaskr\u00e1na \u00ed lok kaflans um Einstein og afst\u00e6\u00f0iskenninguna h\u00e9r a\u00f0 framan sem og a\u00f0ra \u00ed lok f\u00e6rslunnar).<\/p>\n<p>M\u00e9r finnst h\u00f6fundurinn n\u00e1lgast vi\u00f0fangsefni\u00f0 \u00e1 \u00e1hugaver\u00f0an h\u00e1tt og st\u00edllinn er skemmtilega einkennandi fyrir l\u00f6ngu li\u00f0inn t\u00edma. \u00c9g leyfi m\u00e9r \u00fev\u00ed a\u00f0 vitna nokku\u00f0 oft \u00ed or\u00f0 \u00deorkels h\u00e9r \u00e1 eftir.<\/p>\n<p>\u00cd upphafi v\u00edsar \u00deorkell til greina \u00d3lafs Dan\u00edelssonar fr\u00e1 1921 og 1922 og eftir stuttan ingang um \u201ekjarnann \u00ed kenningu Einsteins\u201c segir hann:<\/p>\n<blockquote><p>\u00dat fr\u00e1 \u00feessu m\u00e1 n\u00fa finna margt merkilegt, sem \u00ed flj\u00f3tu brag\u00f0i sko\u00f0a\u00f0 vir\u00f0ist ekkert eiga skylt vi\u00f0 afst\u00e6\u00f0iskenninguna. Jeg vil n\u00fa geta um sumt af \u00feessu, og vel \u00fe\u00e1 \u00fea\u00f0, sem h\u00e6gt hefir veri\u00f0 a\u00f0 pr\u00f3fa me\u00f0 tilraunum e\u00f0a sty\u00f0st vi\u00f0 einhverjar athuganir.<\/p><\/blockquote>\n<p>\u00de\u00f3tt titill greinarinnar v\u00edsi a\u00f0eins til tilraunar Michelsons, tekur \u00deorkell alls fyrir fimm afst\u00e6\u00f0ileg fyrirb\u00e6ri. \u00deau eru hra\u00f0ah\u00e1\u00f0ur massi, brautarsn\u00faningur Merk\u00far\u00edusar, lj\u00f3ssveigja \u00ed \u00feyngdarsvi\u00f0i, \u00feyngdarrau\u00f0vik og loks Michelson-Morley tilraunin.\u00a0 \u00cd eftirfarandi umfj\u00f6llun fylgi \u00e9g s\u00f6mu r\u00f6\u00f0 og \u00deorkell.<\/p>\n<p style=\"text-align: center\"><strong>1. Afst\u00e6\u00f0ilegur massi<\/strong><\/p>\n<p>\u00cd \u00f6rstuttri umfj\u00f6llun sinni skrifar \u00deorkell einfaldlega ni\u00f0ur form\u00faluna fyrir afst\u00e6\u00f0ilegan massa hlutar, <em>m<\/em>, sem fall af hra\u00f0a hans, <em>v<\/em>:\u00a0 <em>m <\/em>(<em>v<\/em>) <em>= m<sub>0 <\/sub><\/em>[1 &#8211; (<em>v\/c<\/em>)<sup>2<\/sup>]<sup>-\u00bd<\/sup>. H\u00e9r er <em>c <\/em><a href=\"https:\/\/en.wikipedia.org\/wiki\/Speed_of_light\">lj\u00f3shra\u00f0inn<\/a> \u00ed loftt\u00e6mi og <em>m<sub>0 <\/sub><\/em>er svokalla\u00f0ur <a href=\"https:\/\/en.wikipedia.org\/wiki\/Invariant_mass\">hv\u00edlumassi<\/a> hlutarins. \u00deorkell notar reyndar \u201etransversal massi\u201c fyrir <em>m<\/em>, gamalt or\u00f0alag sem byrja\u00f0 var a\u00f0 nota fyrir daga afst\u00e6\u00f0iskenningar. H\u00e9r er einnig \u00e1st\u00e6\u00f0a til a\u00f0 benda \u00e1, a\u00f0 \u00ed dag tala fr\u00e6\u00f0imenn ekki lengur um afst\u00e6\u00f0ilegan massa hlutar. \u00deess \u00ed sta\u00f0 er unni\u00f0 me\u00f0 st\u00e6r\u00f0ina <em>E\/c<\/em><sup>2<\/sup>, \u00fear sem <em>E<\/em> er heildarorka hlutarins. Me\u00f0 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Mass_in_special_relativity\">massa<\/a> er n\u00fa \u00e1vallt \u00e1tt vi\u00f0 <em>m<sub>0<\/sub><\/em>.<\/p>\n<p>N\u00e6st v\u00edsar \u00deorkell til svokalla\u00f0ra <a href=\"https:\/\/en.wikipedia.org\/wiki\/Kaufmann%E2%80%93Bucherer%E2%80%93Neumann_experiments\">Kaufmann\u2013Bucherer\u2013Neumann tilrauna<\/a>, \u00e1n \u00feess \u00fe\u00f3 a\u00f0 nefna \u00fe\u00e6r \u00e1 nafn og segir einfaldlega:\u00a0 \u201eTilraunirnar koma heim vi\u00f0 form\u00e1lann\u201c.<\/p>\n<div id=\"attachment_10659\" class=\"wp-caption aligncenter\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-10659\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/06\/mass_vs_speed-300x197.jpg\" alt=\"\" width=\"467\" height=\"306\" aria-describedby=\"caption-attachment-10659\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/mass_vs_speed-300x197.jpg 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/mass_vs_speed.jpg 558w\" sizes=\"auto, (max-width: 467px) 100vw, 467px\" \/><\/p>\n<p id=\"caption-attachment-10659\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Myndin s\u00fdnir ni\u00f0urst\u00f6\u00f0ur m\u00e6linga \u00e1 \u00fev\u00ed, hvernig afst\u00e6\u00f0ilegur massi rafeinda breytist me\u00f0 vaxandi hra\u00f0a. Heila l\u00ednan s\u00fdnir sp\u00e1 takm\u00f6rku\u00f0u afst\u00e6\u00f0iskenningarinnar. M\u00e6lingarnar voru ger\u00f0ar \u00e1 \u00e1runum 1909-15 og \u00deorkell hefur \u00f6rugglega haft vitneskju um \u00fe\u00e6r \u00e1ri\u00f0 1926. Teikning \u00far b\u00f3kinni <em>Special Relativity<\/em> eftir A. P. French, 1968, bls. 23.<\/span><\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<p style=\"text-align: center\"><strong>2. Brautarsn\u00faningur Merk\u00far\u00edusar<\/strong><\/p>\n<p>\u00c1ri\u00f0 1609 setti Kepler fram fyrstu tv\u00f6 l\u00f6gm\u00e1lin af \u00feremur, sem jafnan eru <a href=\"https:\/\/en.wikipedia.org\/wiki\/Kepler's_laws_of_planetary_motion\">vi\u00f0 hann kennd<\/a> (hi\u00f0 \u00feri\u00f0ja kom ekki fyrr en 1619). Sj\u00f6t\u00edu og \u00e1tta \u00e1rum s\u00ed\u00f0ar, e\u00f0a 1687, nota\u00f0i Newton svo <a href=\"https:\/\/en.wikipedia.org\/wiki\/Newton%27s_law_of_universal_gravitation\">\u00feyngdarl\u00f6gm\u00e1l<\/a> sitt og <a href=\"https:\/\/en.wikipedia.org\/wiki\/Newton%27s_laws_of_motion\">hreyfil\u00f6gm\u00e1l<\/a> til a\u00f0 lei\u00f0a \u00fat Keplersl\u00f6gm\u00e1lin \u00e1 snilldarlegan h\u00e1tt.<\/p>\n<p>Fyrsta l\u00f6gm\u00e1l Keplers segir, a\u00f0 brautir reikistjarnanna s\u00e9u sporbaugar me\u00f0 s\u00f3lina \u00ed \u00f6\u00f0rum brennipunkti. Newton \u00e1tta\u00f0i sig flj\u00f3lega \u00e1 \u00fev\u00ed, a\u00f0 \u00feetta var einungis n\u00e1lgun og a\u00f0 brautirnar yr\u00f0u fyrir truflunum vegna \u00feyngdar\u00e1hrifa fr\u00e1 \u00f6\u00f0rum reikistj\u00f6rnum. Ein af aflei\u00f0ingunum er til d\u00e6mis svokalla\u00f0ur brautarsn\u00faningur, sem l\u00fdsa m\u00e1 \u00feannig, a\u00f0 me\u00f0 t\u00edmanum <a href=\"https:\/\/en.wikipedia.org\/wiki\/Two-body_problem_in_general_relativity#Apsidal_precession\">sn\u00fdst lang\u00e1s brautarsporbaugs<\/a> s\u00e9rhverrar reikistj\u00f6rnu h\u00e6gt og r\u00f3lega um s\u00f3lina. Hi\u00f0 sama gildir \u00fe\u00e1 auglj\u00f3slega um s\u00f3ln\u00e1ndina (perihelium).<\/p>\n<p>\u00c1ri\u00f0 1859 gaf hinn mikli reiknimeistari, <a href=\"https:\/\/en.wikipedia.org\/wiki\/Urbain_Le_Verrier\">U. Le Verrier<\/a>, \u00fat ni\u00f0urst\u00f6\u00f0ur truflanareikninga, sem hann haf\u00f0i gert \u00e1 braut Merk\u00far\u00edusar. Samkv\u00e6mt \u00feeim \u00e1tti s\u00f3ln\u00e1nd hnattarins a\u00f0 f\u00e6rast til um 527 bogasek\u00fandur \u00e1 \u00f6ld, en s\u00e1 galli var \u00e1 gj\u00f6f Njar\u00f0ar, a\u00f0 samkv\u00e6mt m\u00e6lingum \u00feess t\u00edma var f\u00e6rslan meiri, e\u00f0a sem nam 565 bogasek\u00fandum \u00e1 \u00f6ld. Le Verrier fann enga a\u00f0ra lei\u00f0 til a\u00f0 \u00fatsk\u00fdra mismuninn, 38 bogasek\u00fandur \u00e1 \u00f6ld, en a\u00f0 stinga upp \u00e1 \u00fev\u00ed, a\u00f0 hann stafa\u00f0i af \u00feyngdartruflunum fr\u00e1 \u00e1\u00f0ur \u00f3\u00feekktum hnetti, <a href=\"https:\/\/en.wikipedia.org\/wiki\/Vulcan_(hypothetical_planet)\">V\u00falkan<\/a>, sem gengi um s\u00f3lina innan vi\u00f0 braut Merk\u00far\u00edusar. Tilg\u00e1tan reyndist r\u00f6ng, en hin skemmtilega saga um \u00feessa og a\u00f0rar tilg\u00e1tur, sem og leitina a\u00f0 V\u00falkan, ver\u00f0ur ekki s\u00f6g\u00f0 h\u00e9r.<\/p>\n<p>Stj\u00f6rnufr\u00e6\u00f0ingurinn <a href=\"https:\/\/en.wikipedia.org\/wiki\/Simon_Newcomb\">S. Newcomb<\/a> endurb\u00e6tti \u00fatreikninga Le Verriers \u00e1ri\u00f0 1882 og me\u00f0 \u00fev\u00ed a\u00f0 sty\u00f0jast vi\u00f0 betri m\u00e6lingar \u00e1 braut Merk\u00far\u00edusar s\u00fdndi hann fram \u00e1, a\u00f0 \u201eumframf\u00e6rsla\u201c s\u00f3ln\u00e1ndarinnar nam 43 bogasek\u00fandum \u00e1 \u00f6ld \u00ed sta\u00f0 38.<\/p>\n<div id=\"attachment_10661\" class=\"wp-caption aligncenter\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-10661\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/06\/Mercury-perih-300x169.jpg\" alt=\"\" width=\"468\" height=\"264\" aria-describedby=\"caption-attachment-10661\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/Mercury-perih-300x169.jpg 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/Mercury-perih-768x432.jpg 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/Mercury-perih.jpg 800w\" sizes=\"auto, (max-width: 468px) 100vw, 468px\" \/><\/p>\n<p id=\"caption-attachment-10661\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">Teikningin \u00e1 a\u00f0 s\u00fdna, hvernig s\u00f3ln\u00e1nd Merk\u00far\u00edusar f\u00e6rist til um 575 bogasek\u00fandur (9,5 bogam\u00edn\u00fatur) \u00e1 \u00f6ld. F\u00e6rslan stafar fyrst og fremst af samanlag\u00f0ri \u00feyngdarverkun (truflunum) annarra reikistjarna en um 7,5%, e\u00f0a 43 bogasek\u00fandur \u00e1 \u00f6ld, eru til komin vegna afst\u00e6\u00f0ilegra \u00feyngdar\u00e1hrifa s\u00f3lar. Mynd: Veraldarvefurinn.<\/span><\/p>\n<\/div>\n<p>\u00cd n\u00f3vember 1915 nota\u00f0i Einstein hina gl\u00e6nn\u00fdju kenningu s\u00edna um \u00feyngdina til a\u00f0 reikna \u00fat afst\u00e6\u00f0ileg \u00feyngdar\u00e1hrif s\u00f3larinnar \u00e1 braut d\u00e6miger\u00f0ar reikistj\u00f6rnu. Ni\u00f0ursta\u00f0an var s\u00fa, a\u00f0 \u00ed hverri umfer\u00f0 valda \u00feau h\u00e6gum sn\u00faningi \u00e1 lang\u00e1s sporbaugsins um horni\u00f0 \u0394<em>\u03c6<\/em>, \u00fear sem \u0394<em>\u03c6<\/em> = 6\u03c0<em>GM\/c<\/em><sup>2<\/sup><em>a<\/em>(1 &#8211; <em>e<\/em><sup>2<\/sup>) \u00ed einingunni rad\u00edan.\u00a0 H\u00e9r er <em>G<\/em> \u00feyngdarstu\u00f0ull Newtons, <em>M<\/em> massi s\u00f3larinnar, <em>a<\/em> h\u00e1lfur lang\u00e1s sporbaugsins og <em>e<\/em> hringvik hans. Fyrir Merk\u00far\u00edus nemur sn\u00faningurinn 5,0191 x 10<sup>-7<\/sup> rad\u00ed\u00f6num \u00ed hverri umfer\u00f0, sem jafngildir 42,98 bogasek\u00fandum \u00e1 \u00f6ld.<\/p>\n<p>\u00cd grein sinni afgrei\u00f0ir \u00deorkell \u00feessa miklu og merkilegu s\u00f6gu einfaldlega me\u00f0 or\u00f0unum:<\/p>\n<blockquote><p>Afst\u00e6\u00f0iskenningin sk\u00fdrir \u00feessa breytingu \u00e1 s\u00f3larn\u00e1munda Merk\u00fars og \u00e1tti h\u00fan a\u00f0 vera 43&#8243;. \u00deetta v\u00e6ri \u00e1g\u00e6t sta\u00f0festing \u00e1 kenningunni. En menn f\u00f3ru a\u00f0 rannsaka betur athuganirnar og komust a\u00f0 \u00feeirri ni\u00f0urst\u00f6\u00f0u a\u00f0 breytingin v\u00e6ri eigi nema 38&#8243; e\u00f0a jafnvel 29&#8243;, og \u00fe\u00e1 var\u00f0 samr\u00e6mi\u00f0 mi\u00f0ur gott og \u00feetta litill stu\u00f0ningur afst\u00e6\u00f0iskenningunni.<\/p><\/blockquote>\n<p>Hva\u00f0an ni\u00f0ursta\u00f0an 29&#8243; er komin, veit \u00e9g ekki.<\/p>\n<ul>\n<li>Wikipedia: <a href=\"https:\/\/en.wikipedia.org\/wiki\/Tests_of_general_relativity#Perihelion_precession_of_Mercury\">Brautarsn\u00faningur Merk\u00far\u00edusar<\/a>.<\/li>\n<li>J. Earman, M. Janssen og J. D. Norton, 1993: <a href=\"https:\/\/books.google.is\/books?id=mCOtbqBPNhQC&amp;source=gbs_navlinks_s\">The Attraction of Gravitation: New Studies in the History of General Relativity<\/a>.\u00a0 Sj\u00e1 bls. 129-172.<\/li>\n<li>C. M. Will, 2018: <a href=\"https:\/\/arxiv.org\/pdf\/1802.05304.pdf\">A new general relativistic contribution to Mercury&#8217;s perihelion advance<\/a>.<\/li>\n<\/ul>\n<p>\u00dev\u00ed mi\u00f0ur fjallar almanaksmeistarinn \u00deorkell \u00deorkelsson um lj\u00f3ssveigjum\u00e6lingarnar (sj\u00e1 n\u00e6sta li\u00f0) me\u00f0 \u00e1l\u00edka stuttaralegum h\u00e6tti og brautarsn\u00faninginn. Hins vegar er umfj\u00f6llun hans um \u00feyngdarrau\u00f0vik og tilraun Michelsons mun \u00edtarlegri og vanda\u00f0ri (sj\u00e1 li\u00f0i 4 og 5).<\/p>\n<p style=\"text-align: center\"><strong>3. Sveigja lj\u00f3ss \u00ed \u00feyngdarsvi\u00f0i<\/strong><\/p>\n<p>H\u00e9r a\u00f0 framan var r\u00e6tt stuttlega um \u00fatreikninga Einsteins \u00e1 afst\u00e6\u00f0ilegri lj\u00f3ssveigju \u00e1ri\u00f0 1915 og einnig um <a href=\"https:\/\/uni.hi.is\/einar\/2019\/05\/30\/old-lidin-fra-solmyrkvanum-mikla-1919\/\">s\u00f3lmyrkvam\u00e6lingarnar fr\u00e6gu \u00e1ri\u00f0 1919<\/a>. Frekari umfj\u00f6llun um \u00feetta \u00e1hugaver\u00f0a efni er me\u00f0al annars a\u00f0 finna h\u00e9r:<\/p>\n<ul>\n<li>P. Coles, 2001: <a href=\"https:\/\/cds.cern.ch\/record\/489163\/files\/0102462.pdf\">Einstein, Eddington and the 1919 Eclipse<\/a>.<\/li>\n<li>C. M. Will, 2015: <a href=\"https:\/\/arxiv.org\/pdf\/1409.7812.pdf\">The 1919 measurement of the deflection of light<\/a>.<\/li>\n<li>J. Earman og C. Glymour,1980: <a href=\"http:\/\/newt.phys.unsw.edu.au\/~jkw\/phys3550\/Eclipse\/Earman_Glymour_1980.pdf\">Relativity and Eclipses: The British Eclipse Expedition of 1919 and its Predecessors<\/a>.<\/li>\n<li>D. Kennefick, 2009: <a href=\"http:\/\/www.physics.rutgers.edu\/~jackph\/2012f\/kennefick_phystoday_09.pdf\">Testing relativity from the 1919 eclipse &#8211; a question of bias<\/a>.<\/li>\n<\/ul>\n<p>\u00cd almennu afst\u00e6\u00f0iskenningunni er sveigjuhorn lj\u00f3sgeisla, sem r\u00e9tt sleikir yfirbor\u00f0 venjulegs hnattar, gefi\u00f0 me\u00f0 form\u00falunni\u00a0 <em>\u03b8 = <\/em>4<em>GM\/Rc<\/em><sup>2<\/sup> \u00fear sem <em>\u03b8<\/em> er sveigjuhorni\u00f0 \u00ed rad\u00edan, <em>M<\/em> massi hnattarins og <em>R<\/em> rad\u00edus hans. Ef <em>M<\/em> er gefinn upp \u00ed s\u00f3larm\u00f6ssum og <em>R<\/em> \u00ed s\u00f3larrad\u00edum, m\u00e1 skrifa form\u00faluna sem <em>\u03b8 = <\/em>1,75<em> M\/R<\/em> bogasek\u00fandur. \u00deannig er sveigjuhorni\u00f0 vi\u00f0 s\u00f3laryfirbor\u00f0i\u00f0 1,75 bogasek\u00fandur.<\/p>\n<div id=\"attachment_9634\" class=\"wp-caption aligncenter\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-9634\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/04\/Mynd_2-300x120.png\" alt=\"\" width=\"445\" height=\"178\" aria-describedby=\"caption-attachment-9634\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/04\/Mynd_2-300x120.png 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/04\/Mynd_2-768x307.png 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/04\/Mynd_2.png 1025w\" sizes=\"auto, (max-width: 445px) 100vw, 445px\" \/><\/p>\n<p id=\"caption-attachment-9634\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">\u00deessi skemmtilega myndr\u00e6na l\u00fdsing \u00e1 sveigju lj\u00f3ss \u00ed \u00feyngdarsvi\u00f0i er \u00far grein \u00d3lafs Dan\u00edelssonar <a href=\"http:\/\/timarit.is\/view_page_init.jsp?gegnirId=000560271\">um afst\u00e6\u00f0iskenninguna<\/a> fr\u00e1 1922. <em>St<\/em> er fjarl\u00e6g stjarna, <em>S<\/em> er s\u00f3lin og <em>J<\/em> j\u00f6r\u00f0in. Lesa m\u00e1 sk\u00fdringar h\u00f6fundar \u00e1 bls. 49-50 \u00ed greininni, en \u00ed stuttu m\u00e1li m\u00e1 segja, a\u00f0 \u00fearna beitir hann jafngildisl\u00f6gm\u00e1li Einsteins til a\u00f0 sannf\u00e6ra lesendur um \u00fea\u00f0, a\u00f0 lj\u00f3si\u00f0 (geislinn g) sveigi af lei\u00f0 vi\u00f0 \u00fea\u00f0 a\u00f0 fara fram hj\u00e1 s\u00f3linni.<\/span><\/p>\n<\/div>\n<p>\u00dea\u00f0 vir\u00f0ist ekki hafa veri\u00f0 \u00e1 margra vitor\u00f0i h\u00e9r heima \u00e1ri\u00f0 1926, a\u00f0 lj\u00f3ssveigjum\u00e6lingar Bretanna fr\u00e1 1919 h\u00f6f\u00f0u \u00feegar veri\u00f0 sta\u00f0festar \u00e1ri\u00f0 1922. \u00dear var um a\u00f0 r\u00e6\u00f0a s\u00e9rlega vanda\u00f0ar myrkvam\u00e6lingar stj\u00f6rnufr\u00e6\u00f0inga fr\u00e1 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Lick_Observatory\">Lick athugunarst\u00f6\u00f0inni<\/a>, sem ger\u00f0ar voru \u00ed \u00c1stral\u00edu:<\/p>\n<ul>\n<li>W. W. Campbell og R. Trumpler, 1923: <a href=\"http:\/\/articles.adsabs.harvard.edu\/\/full\/1923PASP...35..158C\/0000158.000.html\">Observations on the Deflection of Light in Passing Through the Sun&#8217;s Gravitational Field, Made During the Total Solar Eclipse of September 21, 1922<\/a>.<\/li>\n<li>R. R. Burman og P. M. Jeffery, 1990: <a href=\"http:\/\/articles.adsabs.harvard.edu\/\/full\/1990PASAu...8..312B\/0000312.000.html\">Wallal: The 1922 Eclipse Expedition<\/a>.<\/li>\n<li>J. Crelinsten, 1983: <a href=\"https:\/\/www.jstor.org\/stable\/27757525?seq=1#page_scan_tab_contents\">William Wallace Campbell and the &#8220;Einstein Problem&#8221;: An Observational Astronomer Confronts the Theory of Relativity<\/a>.<\/li>\n<\/ul>\n<p>\u00dea\u00f0 er \u00fev\u00ed l\u00edti\u00f0 anna\u00f0 en \u00feekkingarleysi, sem getur afsaka\u00f0 eftirfarandi umm\u00e6li \u00deorkels \u00ed grein hans (bls. 21-22):<\/p>\n<blockquote><p>Lj\u00f3sgeislar sem fara fram hj\u00e1 s\u00f3lunni eiga a\u00f0 breyta stefnu, samkv. afst\u00e6\u00f0iskenningunni, \u00e1 sama h\u00e1tt og steinn e\u00f0a hver annar hlutur mundi \u00e1 \u00feeirri lei\u00f0 breyta stefnu sinni, ef honum v\u00e6ri kasta\u00f0 me\u00f0 hra\u00f0a lj\u00f3ssins. \u00de\u00e1 er almyrkvi ver\u00f0ur \u00e1 s\u00f3lu m\u00e1 pr\u00f3fa \u00feetta. Stj\u00f6rnurnar, sem \u00e6ttu a\u00f0 sj\u00e1st rjett hj\u00e1 s\u00f3lunni, vir\u00f0ast breyta afst\u00f6\u00f0u ofurl\u00edti\u00f0, vegna \u00feess a\u00f0 geislarnir fr\u00e1 \u00feeim ger\u00f0u sveig \u00e1 sig, er \u00feeir f\u00f3ru fram hj\u00e1 s\u00f3lunni. M\u00e6lingar hjer a\u00f0 l\u00fatandi koma vel heim vi\u00f0 afst\u00e6\u00f0iskenninguna. En \u00ed rauninni ver\u00f0ur \u00feetta l\u00edtil s\u00f6nnun. Lj\u00f3ssveigjuna m\u00e1 sk\u00fdra \u00e1 margan annan h\u00e1tt, t. d. sem lj\u00f3sbrot.<\/p><\/blockquote>\n<p>Hugmyndum \u00feess efnis, a\u00f0\u00a0 lj\u00f3ssveigjan orsakist ekki af \u00feyngdinni, heldur einhverju \u00f6\u00f0ru, til d\u00e6mis lj\u00f3sbroti \u00ed hugsanlegum \u201elofthj\u00fap\u201c s\u00f3lar, var hreyft\u00a0 flj\u00f3tlega eftir a\u00f0 tilkynnt var um m\u00e6lingar Breta \u00ed n\u00f3vember 1919. \u00cd grein \u00feeirra um m\u00e6lingarnar fr\u00e1 \u00fev\u00ed \u00ed \u00e1rsbyrjun 1920 er \u00feetta teki\u00f0 fyrir og afsanna\u00f0 (sj\u00e1 bls. 292-93):<\/p>\n<ul>\n<li>F. W. Dyson, A. S. Eddington, C. Davidson, 1920: <a href=\"http:\/\/w.astro.berkeley.edu\/~kalas\/labs\/documents\/dyson1920.pdf\">A Determination of the Deflection of Light by the Sun&#8217;s Gravitational Field, from Observations made at the Total Eclipse of May 29, 1919<\/a>.<\/li>\n<\/ul>\n<p>Telja m\u00e1 n\u00e6r fullv\u00edst, a\u00f0 \u00deorkell hafi ekki haft a\u00f0gang a\u00f0 \u00feessari fr\u00e6gu grein.<\/p>\n<p style=\"text-align: center\"><strong>4. \u00deyngdarrau\u00f0vik<\/strong><\/p>\n<p>\u00c1ri\u00f0 1924 haf\u00f0i <a href=\"https:\/\/en.wikipedia.org\/wiki\/Arthur_Eddington\">A. S. Eddington<\/a> samband vi\u00f0 bandar\u00edska stj\u00f6rnufr\u00e6\u00f0inginn <a href=\"https:\/\/en.wikipedia.org\/wiki\/Walter_Sydney_Adams\">W. S. Adams<\/a> og spur\u00f0i hann um m\u00f6guleika \u00feess a\u00f0 m\u00e6la <a href=\"https:\/\/en.wikipedia.org\/wiki\/Gravitational_redshift\">\u00feyngdarrau\u00f0viki\u00f0<\/a> \u00ed lj\u00f3si hv\u00edta dvergsins <a href=\"https:\/\/en.wikipedia.org\/wiki\/Sirius#Sirius_B\">S\u00edr\u00edusar B<\/a>. Eddington var fremsti stjarne\u00f0lisfr\u00e6\u00f0ingur s\u00edns t\u00edma og helsti m\u00e1lsvari afst\u00e6\u00f0iskenningarinnar, fyrir utan Einstein sj\u00e1lfan. Hann haf\u00f0i gegnt veigamiklu hlutverki \u00ed lj\u00f3ssveigjum\u00e6lingunum \u00e1ri\u00f0 1919 og nota\u00f0i ni\u00f0urst\u00f6\u00f0urnar \u00f3spart til a\u00f0 vekja almenna athygli \u00e1 afst\u00e6\u00f0iskenningunni og mikilv\u00e6gi hennar.<\/p>\n<div id=\"attachment_11114\" class=\"wp-caption aligncenter\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-11114\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/06\/Sirius_A_and_B_Hubble_photo.editted-275x300.png\" alt=\"\" width=\"362\" height=\"394\" aria-describedby=\"caption-attachment-11114\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/Sirius_A_and_B_Hubble_photo.editted-275x300.png 275w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/Sirius_A_and_B_Hubble_photo.editted.png 369w\" sizes=\"auto, (max-width: 362px) 100vw, 362px\" \/><\/p>\n<p id=\"caption-attachment-11114\" class=\"wp-caption-text\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/Sirius\"><span style=\"font-size: 10pt\">S\u00edr\u00edus<\/span><\/a><span style=\"font-size: 10pt\">, bjartasta s\u00f3lstjarnan \u00e1 n\u00e6turhimninum er \u00ed raun tv\u00edstirni. <span class=\"mw-mmv-title\">Sirius A (st\u00f3ra stjarnan \u00e1 mi\u00f0ri mynd) er venjuleg s\u00f3lstjarna \u00e1 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Main_sequence\">meginskei\u00f0i<\/a>, en Sirius B (litli lj\u00f3sdepillinn sem \u00f6rin bendir \u00e1) er <a href=\"https:\/\/en.wikipedia.org\/wiki\/White_dwarf\">hv\u00edtur dvergur<\/a>. A\u00f0rir deplar, l\u00ednurnar og hringirnir \u00e1 myndinni eru lj\u00f3sfyrirb\u00e6ri \u00ed myndav\u00e9lab\u00fana\u00f0i. <\/span>Myndin er tekin me\u00f0 Hubble-sj\u00f3naukanum. Sj\u00e1 n\u00e1nar <a href=\"https:\/\/www.spacetelescope.org\/images\/heic0516a\/\">h\u00e9r<\/a>.<\/span><\/p>\n<\/div>\n<p>\u00c1\u00f0ur en lengra er haldi\u00f0 er r\u00e9tt a\u00f0 nefna, a\u00f0 \u00e1 \u00feessum t\u00edma var \u00fea\u00f0 regla, frekar en undantekning, a\u00f0 gefa rau\u00f0vik almennt upp sem tilsvarandi \u201e<a href=\"https:\/\/en.wikipedia.org\/wiki\/Doppler_effect\">Doppler-hra\u00f0a<\/a>\u201c, <em>v = cz<\/em>, \u00fear sem <em>z =\u00a0 \u0394\u03bb\/\u03bb<\/em><sub>0<\/sub> er rau\u00f0viki\u00f0 og <em>\u03bb <\/em>bylgjulengdin. Samkv\u00e6mt almennu afst\u00e6\u00f0iskenningunni er \u00feyngdarrau\u00f0vik lj\u00f3ss fr\u00e1 venjulegum hnetti me\u00f0 massa <em>M<\/em> og rad\u00edus <em>R<\/em> gefi\u00f0 me\u00f0 form\u00falunni <em>z = GM\/Rc<\/em><sup>2 <\/sup>(athugi\u00f0 a\u00f0 \u00deorkell notar <em>k<\/em> \u00ed sta\u00f0 <em>G<\/em>). Ef <em>M<\/em> er gefinn upp \u00ed s\u00f3larm\u00f6ssum og <em>R<\/em> \u00ed s\u00f3larrad\u00edum, m\u00e1 skrifa \u00feyngdarrau\u00f0viks-form\u00faluna sem <em>v = <\/em>0,6<em> M\/R<\/em> km\/s. Samkv\u00e6mt \u00fev\u00ed svarar \u00feyngdarrau\u00f0vik s\u00f3larlj\u00f3ssins til hra\u00f0ans 0,6 km\/s (e\u00f0a um 2 \u00fe\u00fasund km \u00e1 klst). \u00c1 \u00feessum t\u00edma h\u00f6f\u00f0u \u00feegar veri\u00f0 ger\u00f0ar margar tilraunir til a\u00f0 m\u00e6la rau\u00f0vik Fraunhofer-l\u00ednanna \u00ed s\u00f3larr\u00f3finu, en \u00feegar upp var sta\u00f0i\u00f0 reyndust allar ni\u00f0urst\u00f6\u00f0urnar \u00f3markt\u00e6kar.<\/p>\n<p>Br\u00e9f Eddingtons fr\u00e1 1924 var\u00f0 til \u00feess, a\u00f0 Adams h\u00f3f litr\u00f3fsm\u00e6lingar \u00e1 S\u00edr\u00edusi B me\u00f0 st\u00e6rsta sj\u00f3nauka heims \u00e1 \u00feeim t\u00edma, <a href=\"https:\/\/en.wikipedia.org\/wiki\/Mount_Wilson_Observatory#Hooker_telescope\">100 \u00feumlunga spegilsj\u00f3naukanum<\/a> \u00e1\u00a0 Wilsonsfjalli. \u00c1ri\u00f0 1925 taldi hann sig vera kominn me\u00f0 \u00f3tv\u00edr\u00e6\u00f0ar ni\u00f0urst\u00f6\u00f0ur, sem v\u00e6ru \u00ed fullu samr\u00e6mi vi\u00f0 \u00fatreikninga Eddingtons fr\u00e1 \u00e1rinu \u00e1\u00f0ur. Eddington haf\u00f0i gert r\u00e1\u00f0 fyrir, a\u00f0 yfirbor\u00f0shiti dvergsins v\u00e6ri 8000 gr\u00e1\u00f0ur og me\u00f0 \u00fev\u00ed a\u00f0 nota \u00fe\u00e1 t\u00f6lu, \u00e1samt \u00f6\u00f0rum \u00feekktum m\u00e6list\u00e6r\u00f0um, f\u00e9kk hann, a\u00f0 rad\u00edus dvergsins v\u00e6ri 19.600 km og rau\u00f0viki\u00f0 20 km\/s. Einnig a\u00f0 me\u00f0al\u00fe\u00e9ttni dvergsins v\u00e6ri 53.000 sinnum meiri en vatns. M\u00e6lini\u00f0urst\u00f6\u00f0ur Adams voru 18.000 km fyrir rad\u00edus dvergsins og 21 km\/s fyrir rau\u00f0viki\u00f0.<\/p>\n<ul>\n<li>A. S. Eddington, 1924: <a href=\"http:\/\/articles.adsabs.harvard.edu\/full\/1924MNRAS..84..308E\">On the relation between the masses and luminosities of the stars<\/a>. (Sj\u00e1 bls. 322.)<\/li>\n<li>W. S. Adams, 1925: <a href=\"https:\/\/www.pnas.org\/content\/pnas\/11\/7\/382.full.pdf\">The Relativity Displacement of the Spectral Lines in the Companion of Sirius<\/a>.<\/li>\n<\/ul>\n<p>\u00cd umfj\u00f6llun sinni um \u00feetta efni fer \u00deorkell \u00deorkelsson \u00ed gegnum umtalsver\u00f0a reikninga, \u00fear sem hann beitir eing\u00f6ngu s\u00edgildri e\u00f0lisfr\u00e6\u00f0i. Fyrst notar hann aflfr\u00e6\u00f0i Newtons og jafngildisl\u00f6gm\u00e1l Einsteins til finna \u00feyngdarau\u00f0viki\u00f0 vi\u00f0 yfirbor\u00f0 s\u00f3lar og f\u00e6r r\u00e9tta ni\u00f0urst\u00f6\u00f0u, <em>z<\/em> =\u00a0 0,000002, sem samsvarar Doppler-hra\u00f0anum <em>v<\/em> = 0,6 km\/s. Um \u00feetta segir \u00ed greininni:<\/p>\n<blockquote><p>\u00deetta er l\u00edtil breyting \u00e1 \u00f6ldubreiddinni, en samt m\u00e6lanleg, og e\u00f0lisfr\u00e6\u00f0ingar og stj\u00f6rnufr\u00e6\u00f0ingar hafa \u00fe\u00f3tst geta fundi\u00f0, a\u00f0 m\u00e6lingarnar k\u00e6mu heim vi\u00f0 reikninginn. En a\u00f0rir telja \u00feetta litla s\u00f6nnun, \u00fev\u00ed a\u00f0 m\u00e6lingin \u00e1 \u00feessari litlu breytingu getur ekki or\u00f0i\u00f0 n\u00e1kv\u00e6m og margt sem truflar. Straumar \u00ed gufuhvolfi s\u00f3larinnar hafa svipa\u00f0ar verkanir samkv\u00e6mt reglu Dopplers; ennfremur getur \u00fer\u00fdstingur haft \u00e1hrif \u00ed s\u00f6mu \u00e1tt, og vandi a\u00f0 sj\u00e1 \u00feess vegna, hva\u00f0an \u00e1hrifin stafa. En n\u00fa hafa menn fundi\u00f0 a\u00f0ra stj\u00f6rnu, \u00fear sem \u00feetta sjest betur. \u00dea\u00f0 er dvergstirni\u00f0, sem hrings\u00f3lar um Sirius.<\/p><\/blockquote>\n<p>\u00deorkell \u00e1kvar\u00f0ar s\u00ed\u00f0an rau\u00f0viki\u00f0 fr\u00e1 S\u00edr\u00edusi B \u00e1 athyglisver\u00f0an h\u00e1tt. Hann notar fyrst s\u00edgilda aflfr\u00e6\u00f0i og m\u00e6lingar \u00e1 \u00e1rlegri hli\u00f0run og birtu S\u00edr\u00edusar til a\u00f0 finna fjarl\u00e6g\u00f0 og lj\u00f3safl tv\u00edstirnisins og massa dvergsins. Hann gefur s\u00e9r sama yfirbor\u00f0shita og Eddington og beitir <a href=\"https:\/\/en.wikipedia.org\/wiki\/Stefan%E2%80%93Boltzmann_law\">Stefan-Boltzmann l\u00f6gm\u00e1linu<\/a> til a\u00f0 reikna st\u00e6r\u00f0ina. A\u00f0 \u00fev\u00ed loknu reiknar \u00deorkell \u00feyngdarrau\u00f0vik dvergstj\u00f6rnunnar og f\u00e6r a\u00f0 <em>z<\/em> = 0,000076 e\u00f0a <em>v<\/em> = 23 km\/s.<\/p>\n<blockquote><p>\u00deessi \u00f6ldubreyting er svo mikil, a\u00f0 vel er h\u00e6gt a\u00f0 m\u00e6la hana. Reyndar gerir Sirius athuganirnar erfi\u00f0ar, \u00fev\u00ed a\u00f0 hann er svo n\u00e1l\u00e6gt dvergnum og margfalt sk\u00e6rari, en samt hefir W. Adams tekist a\u00f0 gera \u00feessar m\u00e6lingar \u00ed stj\u00f6rnuturninum \u00ed Mount Wilson. M\u00e6lingar \u00feessar koma mj\u00f6g vel heim vi\u00f0 afst\u00e6\u00f0iskenninguna.<\/p><\/blockquote>\n<p>Eitt atri\u00f0i vir\u00f0ist \u00fe\u00f3 vefjast fyrir \u00deorkeli, nefnilega hin mikla massa\u00fe\u00e9ttni S\u00edr\u00edusar B:<\/p>\n<blockquote><p>Massi (e\u00f0a \u00feungi) dvergsins <em>[er]<\/em> talinn jafn massa s\u00f3larinnar, en radius hans 35.6 sinnum minni <em>[\u00fe.e. 20 \u00fe\u00fasund km]<\/em>. En \u00fear af lei\u00f0ir, a\u00f0 e\u00f0lis\u00feungi dvergsins er <em>[&#8230;]<\/em> 45000 sinnum meiri en e\u00f0lis\u00feyngd s\u00f3lar, e\u00f0a me\u00f0 \u00f6\u00f0rum or\u00f0um, e\u00f0lis\u00feyngd dvergsins ver\u00f0ur 50\u201460 \u00fe\u00fasund sinnum e\u00f0lis\u00feyngd vatnsins. Fyrir flesta er \u00fea\u00f0 nokku\u00f0 erfitt a\u00f0 \u00e1tta sig \u00e1 \u00feessari miklu e\u00f0lis\u00feyngd, en stj\u00f6rnufr\u00e6\u00f0ingum kva\u00f0 ekkert \u00feykja undarlegt vi\u00f0 hana.<\/p><\/blockquote>\n<p>Svo \u00f3heppilega vill til, a\u00f0 nokkrar st\u00e6r\u00f0anna, sem \u00deorkell notar vi\u00f0 reikningana, eru fjarri r\u00e9ttu lagi. Sem d\u00e6mi m\u00e1 nefna, a\u00f0 \u00fe\u00f3tt hann noti r\u00e9ttan massa er yfirbor\u00f0shiti dvergsins \u00ed raun 3,2 sinnum meiri en \u00deorkell gerir r\u00e1\u00f0 fyrir og st\u00e6r\u00f0in um 3,4 sinnum minni. Rau\u00f0viki\u00f0 sem hann f\u00e6r \u00fat ver\u00f0ur \u00fev\u00ed 3,5 sinnum of l\u00edti\u00f0 og e\u00f0lismassinn um 44 sinnum of l\u00edtill. Ni\u00f0ursta\u00f0a hans er \u00fe\u00f3 \u00ed samr\u00e6mi vi\u00f0 \u00fatreikninga Eddingtons og m\u00e6lingar Adams.<\/p>\n<p>R\u00e9tt er a\u00f0 geta \u00feess, a\u00f0 \u00feyngdarrau\u00f0vik S\u00edr\u00edusar B var ekki m\u00e6lt me\u00f0 \u00f6ruggum h\u00e6tti fyrr en \u00e1ri\u00f0 1971, \u00feegar bandar\u00edskir stj\u00f6rnufr\u00e6\u00f0ingar beindu <a href=\"https:\/\/en.wikipedia.org\/wiki\/Hale_Telescope\">200 \u00feumlunga sj\u00f3naukanum<\/a> \u00e1 Palomarfjalli a\u00f0 dvergnum. Ni\u00f0ursta\u00f0a \u00feeirra var <em>z<\/em> = 89 \u00b1 16 km\/s.<\/p>\n<ul>\n<li>J. L. Greenstein, J. B. Oke og H. L. Shipman, 1971: <a href=\"http:\/\/articles.adsabs.harvard.edu\/full\/1971ApJ...169..563G\">Effective Temperature, Radius, and Gravitational Redshift of Sirius B<\/a>.<\/li>\n<\/ul>\n<p>Ellefu \u00e1rum \u00e1\u00f0ur haf\u00f0i \u00ed fyrsta sinn veri\u00f0 s\u00fdnt fram \u00e1 \u00fea\u00f0 me\u00f0 \u00f3yggjandi h\u00e6tti, a\u00f0 \u00feyngd veldur rau\u00f0viki, n\u00e1kv\u00e6mlega \u00e1 \u00feann h\u00e1tt sem almenna afst\u00e6\u00f0iskenningin segir til um. \u00dea\u00f0 var \u00ed hinni fr\u00e6gri tilraun <a href=\"https:\/\/physics.aps.org\/story\/v16\/st1\">Pounds og Rebka<\/a> \u00e1ri\u00f0 1960. \u00dear beittu \u00feeir svonefndum <a href=\"https:\/\/en.wikipedia.org\/wiki\/M%C3%B6ssbauer_effect\">M\u00f6ssbauerm\u00e6lingum<\/a> til a\u00f0 \u00e1kvar\u00f0a rau\u00f0vik (og einnig bl\u00e1vik) gammageisla \u00ed \u00feyngdarsvi\u00f0i jar\u00f0arinnar.<\/p>\n<ul>\n<li>R. V. Pound og G. A. Rebka Jr., 1960: <a href=\"https:\/\/journals.aps.org\/prl\/abstract\/10.1103\/PhysRevLett.4.337\">Apparent Weight of Photons<\/a>.<\/li>\n<\/ul>\n<p>Eftirfarandi greinar gefa \u00e1g\u00e6tis yfirlit yfir s\u00f6gu hugmynda um \u00feyngdarrau\u00f0vik og fyrstu tilraunirnar til a\u00f0 m\u00e6la \u00fea\u00f0 hj\u00e1 himintunglum:<\/p>\n<ul>\n<li>E. G. Forbes, 1961: <a href=\"https:\/\/www.tandfonline.com\/doi\/abs\/10.1080\/00033796100202601?journalCode=tasc20\">A History of the Solar Red Shift Problem<\/a>.<\/li>\n<li>J. B. Holberg, 2010: <a href=\"http:\/\/articles.adsabs.harvard.edu\/\/full\/2010JHA....41...41H\/0000041.000.html\">Sirius B and the Measurement of the Gravitational Redshift<\/a>.<\/li>\n<li>J. Earman og C. Glymour, 1981: <a href=\"https:\/\/www.cmu.edu\/dietrich\/philosophy\/docs\/glymour\/glymour1981.pdf\">The Gravitational Redshift as a Test of General Relativity: History and Analysis<\/a>.<\/li>\n<\/ul>\n<p style=\"text-align: center\"><strong>5. Tilraun Michelsons og Morleys<br \/>\n<\/strong><\/p>\n<p>Or\u00f0i\u00f0 <em>lj\u00f3svaki<\/em> kemur fyrst fyrir \u00ed \u00fe\u00fd\u00f0ingu J\u00f3nasar Hallgr\u00edmssonar \u00e1 <a href=\"https:\/\/baekur.is\/bok\/000402495\/Stjornufraedi__lett_og_handa\">Stj\u00f6rnufr\u00e6\u00f0i Ursins<\/a>, sem kom \u00fat 1842. Eftir \u00fev\u00ed sem \u00e9g best veit, er \u00fear jafnframt a\u00f0 finna fyrstu l\u00fdsinguna \u00e1 \u00feessu merkilega fyrirb\u00e6ri \u00e1 \u00edslensku (sj\u00e1 bls. 9). \u00deegar n\u00e6r lei\u00f0 aldam\u00f3tunum, kom lj\u00f3svakinn \u00e6 oftar til umr\u00e6\u00f0u h\u00e9r \u00e1 landi, enda virtist hann nau\u00f0synlegur til \u00feess a\u00f0 \u00fatsk\u00fdra fj\u00f6lmargar n\u00fdjar uppg\u00f6tvanir um eiginleika lj\u00f3ssins og \u00fatbrei\u00f0slu \u00feess. \u00c1 hinn b\u00f3ginn ger\u00f0i n\u00fd \u00feekking \u00fea\u00f0 a\u00f0 verkum, a\u00f0 lj\u00f3svakinn var\u00f0 \u00e6 dularfyllri me\u00f0 t\u00edmanum. \u00cd greininni <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=2409517\">Heimur og geimur<\/a> fr\u00e1 1917 fjallar <a href=\"https:\/\/is.wikipedia.org\/wiki\/%C3%9Eorvaldur_Thoroddsen\">\u00deorvaldur Thoroddsen<\/a> all \u00edtarlega um fyrib\u00e6ri\u00f0 (bls. 38-42) og segir me\u00f0al annars:<\/p>\n<blockquote><p>\u00deetta efni, sem ber Ij\u00f3si\u00f0 fr\u00e1 yztu endim\u00f6rkum alheimsins til skilningarvita vorra, hefur veri\u00f0 kalla\u00f0 lj\u00f3svaki (eter e\u00f0a heimseter), og er \u00fe\u00f3 varla h\u00e6gt a\u00f0 kalla \u00fea\u00f0 efni \u00ed vanalegum skilningi, \u00fev\u00ed \u00fea\u00f0 vantar \u00fe\u00e1 eiginlegleika, sem \u00f6nnur \u00e1\u00fereifanleg og loftkynju\u00f0 efni hafa; lj\u00f3svakinn er svo dularfullur a\u00f0 e\u00f0li s\u00ednu, a\u00f0 ranns\u00f3kn v\u00edsindamanna rekur sig alsta\u00f0ar \u00ed v\u00f6r\u00f0urnar, einkennin, sem tilraunirnar s\u00fdna, lenda \u00ed eint\u00f3mum andst\u00e6\u00f0um og endileysum. Me\u00f0 \u00f6\u00f0rum or\u00f0um: lj\u00f3svakinn vir\u00f0ist a\u00f0 mestu leyti fyrir utan takm\u00f6rk mannlegrar skynjanar.<\/p><\/blockquote>\n<p>\u00deorvaldur fjallar ekkert um afst\u00e6\u00f0iskenninguna \u00ed \u00feessari annars \u00e1g\u00e6tu grein, nema hva\u00f0 hann v\u00edsar lesendum ne\u00f0anm\u00e1ls (bls. 33) \u00e1 grein \u00d3lafs Dan\u00edelssonar fr\u00e1 1913. \u00deetta er \u00ed sj\u00e1lfu s\u00e9r ekki undarlegt, \u00fev\u00ed \u00fea\u00f0 var ekki fyrr en um og eftir 1920, sem afst\u00e6\u00f0iskenningin og tilraunir henni\u00a0 tengdar komu til umfj\u00f6llunar h\u00e9r \u00e1 landi. \u00deetta m\u00e1 til d\u00e6mis sj\u00e1 \u00e1 grein \u00deorkels \u00deorkelssonar <a href=\"http:\/\/timarit.is\/view_page_init.jsp?gegnirId=000586134\">um R\u00f6ntgengeisla<\/a> fr\u00e1 1916. \u00dear kemur sk\u00fdrt fram, a\u00f0 h\u00f6fundurinn telur geislana vera bylgjuhreyfingu \u00ed lj\u00f3svakanum. (Sj\u00e1 einnig <em>Vi\u00f0b\u00f3t 1<\/em> aftast \u00ed f\u00e6rslu.)<\/p>\n<p>\u00de\u00f3tt <a href=\"https:\/\/en.wikipedia.org\/wiki\/Albert_A._Michelson\">A. A. Michelson<\/a> hafi fyrst reynt a\u00f0 s\u00fdna fram \u00e1 tilvist <a href=\"https:\/\/en.wikipedia.org\/wiki\/Luminiferous_aether\">lj\u00f3svakanns<\/a> \u00e1ri\u00f0 1881, var \u00e1rangurinn \u00f3fulln\u00e6gjandi og \u00fea\u00f0 var ekki fyrr en \u00e1 \u00e1rinu 1887, sem honum t\u00f3kst a\u00f0 fullkomna m\u00e6linguna \u00ed samvinnu vi\u00f0\u00a0 f\u00e9laga sinn <a href=\"https:\/\/en.wikipedia.org\/wiki\/Edward_W._Morley\">E. W. Morley<\/a>. Af \u00feeirri \u00e1st\u00e6\u00f0u er n\u00fa yfirleitt tala\u00f0 um <a href=\"https:\/\/en.wikipedia.org\/wiki\/Michelson%E2%80%93Morley_experiment\">Michelson-Morley tilraunina<\/a>.<\/p>\n<div id=\"attachment_11172\" class=\"wp-caption aligncenter\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-11172\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/06\/Michelson-Moreley-1-300x221.png\" alt=\"\" width=\"480\" height=\"354\" aria-describedby=\"caption-attachment-11172\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/Michelson-Moreley-1-300x221.png 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/Michelson-Moreley-1.png 674w\" sizes=\"auto, (max-width: 480px) 100vw, 480px\" \/><\/p>\n<p id=\"caption-attachment-11172\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">A. A. Michelson (til vinstri) og E. W. Morley (til h\u00e6gri) um \u00fea\u00f0 leyti, sem \u00feeir framkv\u00e6mdu tilraunina fr\u00e6gu. Myndir: <em>Physics Today<\/em>, ma\u00ed 1987, bls. 50-51.<\/span><\/p>\n<\/div>\n<p>Grundvallarhugmynd Michelssons var s\u00fa a\u00f0 nota v\u00edxlun lj\u00f3ss til a\u00f0 \u00e1kvar\u00f0a hra\u00f0a jar\u00f0ar mi\u00f0a\u00f0 vi\u00f0 lj\u00f3svakann og s\u00fdna \u00feannig fram \u00e1 tilvist vakans. \u00d6llum til mikillar undrunar, og ekki s\u00edst \u00feeim sj\u00e1lfum, komust \u00feeir Morley a\u00f0 \u00feeirri ni\u00f0urst\u00f6\u00f0u, a\u00f0 j\u00f6r\u00f0in st\u00e6\u00f0i kyrr \u00ed lj\u00f3svakanum. \u00deetta var \u00ed hr\u00f3pandi m\u00f3ts\u00f6gn vi\u00f0 s\u00edgilda aflfr\u00e6\u00f0i Newtons og r\u00edkjandi hugmyndir um e\u00f0li lj\u00f3ss og vaka. Ni\u00f0ursta\u00f0an olli \u00fev\u00ed miklu hugarangri me\u00f0al s\u00e9rfr\u00e6\u00f0inga. Margir af fremstu e\u00f0lisfr\u00e6\u00f0ingum heims gl\u00edmdu vi\u00f0 vandam\u00e1li\u00f0 \u00e1rum saman, en eins og fr\u00e6gt er or\u00f0i\u00f0 var \u00fea\u00f0 n\u00fdgr\u00e6\u00f0ingurinn Einstein, sem fann lausnina \u00e1ri\u00f0 1905. Ein af ni\u00f0urst\u00f6\u00f0um hans var s\u00fa, a\u00f0 lj\u00f3svakinn v\u00e6ri \u00f3\u00fearfur og tilg\u00e1tan um tilvist hans \u00fev\u00ed sennilega r\u00f6ng. Um \u00fe\u00e1 s\u00f6gu m\u00e1 lesa n\u00e1nar <a href=\"https:\/\/en.wikipedia.org\/wiki\/History_of_special_relativity\">h\u00e9r<\/a>.<\/p>\n<ul>\n<li>A. A. Michelson og E. W. Morley, 1887: <a href=\"https:\/\/history.aip.org\/exhibits\/gap\/PDF\/michelson.pdf\">On the Relative Motion of the Earth and the Luminiferous Ether<\/a>.<\/li>\n<li>L. S. Swenson, 2012: <a href=\"https:\/\/books.google.is\/books?id=3maxDAAAQBAJ&amp;source=gbs_navlinks_s\">The Ethereal Aether: A History of the Michelson-Morley-Miller Aether-drift Experiments, 1880-1930<\/a>.<\/li>\n<li>Ch. Eisele, A. Yu. Nevsky og S. Schille, 2009: <a href=\"http:\/\/ivanik3.narod.ru\/LasernExper\/Eisele\/PhysRevLett.103.090401.pdf\">Laboratory Test of the Isotropy of Light Propagation at the 10<sup>-17<\/sup> Level<\/a>. Sj\u00e1 einnig <a href=\"https:\/\/physicsworld.com\/a\/michelson-morley-experiment-is-best-yet\/\">fr\u00e9tt um \u00feessa tilraun<\/a>.<\/li>\n<\/ul>\n<p>Eins og \u00e1\u00f0ur hefur komi\u00f0 fram, voru ni\u00f0urst\u00f6\u00f0ur bandar\u00edska e\u00f0lisfr\u00e6\u00f0ingsins <a href=\"https:\/\/en.wikipedia.org\/wiki\/Dayton_Miller\">D. C. Millers<\/a> ein helsta \u00e1st\u00e6\u00f0a \u00feess, a\u00f0 \u00deorkell gaf \u00fat grein s\u00edna um afst\u00e6\u00f0iskenniguna \u00e1ri\u00f0 1926. Miller haf\u00f0i endurteki\u00f0 tilraun \u00feeirra Michelsons og Morleys og taldi sig hafa s\u00fdnt fram \u00e1 hreyfingu jar\u00f0ar \u00ed lj\u00f3svakanum. Fr\u00e9ttir af m\u00e6lingum hans v\u00f6ktu mikla athygli v\u00ed\u00f0a um heim og birtust me\u00f0al annars \u00ed <a href=\"http:\/\/timarit.is\/view_page_init.jsp?pageId=4820838\">Eimrei\u00f0inni<\/a> \u00e1ri\u00f0 1925 (bls. 324-25).<\/p>\n<div id=\"attachment_10592\" class=\"wp-caption aligncenter\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-10592\" src=\"http:\/\/uni.hi.is\/einar\/files\/2019\/06\/ThTh_1926-300x188.png\" alt=\"\" width=\"511\" height=\"320\" aria-describedby=\"caption-attachment-10592\" srcset=\"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/ThTh_1926-300x188.png 300w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/ThTh_1926-1024x641.png 1024w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/ThTh_1926-768x481.png 768w, https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/wp-content\/uploads\/2019\/06\/ThTh_1926.png 1448w\" sizes=\"auto, (max-width: 511px) 100vw, 511px\" \/><\/p>\n<p id=\"caption-attachment-10592\" class=\"wp-caption-text\"><span style=\"font-size: 10pt\">\u00deorkell me\u00f0 st\u00e6r\u00f0fr\u00e6\u00f0ideildarnemum \u00ed 6. bekk C vori\u00f0 1926. Af teikningunni \u00e1 t\u00f6flunni m\u00e1 r\u00e1\u00f0a, a\u00f0 hann hefur veri\u00f0 a\u00f0 \u00fatsk\u00fdra hinn fr\u00e6ga v\u00edxlm\u00e6li Michelsons fyrir bekknum. Fr\u00e1 vinstri: \u00deorkell, Bjarni Sigur\u00f0sson, Einar Sveinsson, G\u00edsli Gestsson, J\u00f3n Stef\u00e1nsson, \u00c1rni B. \u00c1rnason, Ragnar \u00d3lafsson, Ing\u00f3lfur G\u00edslason, Valgar\u00f0 Thoroddsen og J\u00fal\u00edus Sigurj\u00f3nsson. Lj\u00f3smynd: \u00d3lafur Magn\u00fasson.<\/span><\/p>\n<\/div>\n<p>Eftir a\u00f0 hafa \u00fatsk\u00fdrt\u00a0 <a href=\"https:\/\/en.wikipedia.org\/wiki\/Michelson_interferometer\">v\u00edxlm\u00e6li Michelsons<\/a> \u00ed talsver\u00f0um sm\u00e1atri\u00f0um og r\u00e6tt um fyrri ni\u00f0urst\u00f6\u00f0ur \u00feeirra Michelsons og Morleys \u00ed greininni, sn\u00fdr \u00deorkell s\u00e9r a\u00f0 Miller og m\u00e6lingum hans:<\/p>\n<blockquote><p>Pr\u00f3fessor D. C. Miller ger\u00f0i \u00ed mars og apr\u00edl \u00e1ri\u00f0 1921 \u00feessar s\u00f6mu tilraunir \u00e1 n\u00fd \u00ed stj\u00f6rnuturninum \u00e1 Mount Wilson \u00ed Californiu \u00ed 1730 metra h\u00e6\u00f0 yfir sj\u00f3 (37\u00b0 20&#8242; nor\u00f0urbreiddar 121\u00b0 33&#8242; vesturlengdar). Hann fann n\u00fa, a\u00f0 lj\u00f3si\u00f0 var ekki jafn lengi \u00ed b\u00e1\u00f0ar \u00e1ttirnar, og taldist svo til af mun, sem var\u00f0 \u00e1 lj\u00f3s\u00f6ldunum, a\u00f0 uppi \u00e1 Mount Wilson v\u00e6ri lj\u00f3svaka-straumur, sem svara\u00f0i til 1\/3 af hra\u00f0a jar\u00f0ar \u00e1 braut sinni kring um s\u00f3lina.<\/p><\/blockquote>\n<p>Um m\u00e6lingarnar 1925 segir hann:<\/p>\n<blockquote><p>\u00deessar <em>[n\u00fdju]<\/em> m\u00e6lingar pr\u00f3fessors Millers vir\u00f0ast \u00f3samr\u00edmanlegar vi\u00f0 afst\u00e6\u00f0iskenningu Einsteins. Eftir m\u00e6lingunum a\u00f0 d\u00e6ma, dregur j\u00f6r\u00f0in lj\u00f3svakann me\u00f0 sjer \u00e1 hreyfingu sinni; ni\u00f0ur vi\u00f0 yfirbor\u00f0i\u00f0 hefir lj\u00f3svakinn \u00fev\u00ed sem n\u00e6st s\u00f6mu hreyfingu og j\u00f6r\u00f0in, en \u00feegar h\u00e6rra kemur fr\u00e1 yfirbor\u00f0i jar\u00f0ar, ver\u00f0ur meiri munur \u00e1 hreyfingu jar\u00f0ar og lj\u00f3svakans.<\/p><\/blockquote>\n<p>\u00deorkell fjallar s\u00ed\u00f0an um hreyfingu jar\u00f0ar um s\u00f3lina, hra\u00f0a s\u00f3lkerfisins me\u00f0al n\u00e1l\u00e6gra stjarna og loks fer\u00f0alag s\u00f3lar og n\u00e6stu stjarna mi\u00f0a\u00f0 vi\u00f0 \u201estj\u00f6rnuh\u00f3pa geimsins\u201c. \u00de\u00e1 r\u00e6\u00f0ir hann \u00e1lit stj\u00f6rnufr\u00e6\u00f0inga \u00e1 m\u00e6lingum Millers og segir s\u00ed\u00f0an:<\/p>\n<blockquote><p>\u00a0N\u00fa er svo m\u00e1lum komi\u00f0, a\u00f0 annarsvegar stendur afst\u00e6\u00f0iskenning Einsteins, en hinsvegar hin gamla tilraun Michelsons, sem upphaflega var\u00f0 til \u00feess, a\u00f0 afst\u00e6\u00f0iskenningunni var hleypt af stokkunum, en n\u00fa \u00ed h\u00f6ndum Millers hefir brug\u00f0i\u00f0 f\u00e6ti fyrir hana, svo a\u00f0 ekki er anna\u00f0 s\u00fdnilegra, en a\u00f0 anna\u00f0hvort ver\u00f0i h\u00fan afst\u00e6\u00f0iskenningunni a\u00f0 falli, e\u00f0a a\u00f0 m\u00e6lingar Millers sjeu \u00f3n\u00fdtar.<\/p><\/blockquote>\n<p>D\u00f3mur s\u00f6gunnar er \u00f3tv\u00edr\u00e6\u00f0ur: M\u00e6lingar Millers reyndust \u00f3n\u00fdtar og afst\u00e6\u00f0iskenning Einstein stendur n\u00fa traustari f\u00f3tum en nokkru sinni fyrr.<\/p>\n<ul>\n<li>D. C. Miller, 1925: <a href=\"https:\/\/www.jstor.org\/stable\/84909?seq=1#page_scan_tab_contents\">Ether-Drift Experiments at Mount Wilson<\/a>.<\/li>\n<li>R. S. Shankland go fl., 1955: <a href=\"http:\/\/ayuba.fr\/pdf\/shankland1955.pdf\">New Analysis of the Interferometer Observations of Dayton C. Miller<\/a>.<\/li>\n<li>L.S. Swenson, 1970: <a href=\"http:\/\/articles.adsabs.harvard.edu\/\/full\/1970JHA.....1...56S\/0000056.000.html\">The Michelson-Morley-Miller Experiments before and after 1905<\/a>.<\/li>\n<li>R. Lalli, 2012: <a href=\"https:\/\/www.tandfonline.com\/doi\/full\/10.1080\/00033790.2011.637473\">The Reception of Miller\u2019s Ether-Drift Experiments in the USA: The History of a Controversy in Relativity Revolution<\/a>.<\/li>\n<\/ul>\n<p>\u00dea\u00f0 er vi\u00f0 h\u00e6fi a\u00f0 lj\u00faka \u00feessari f\u00e6rslu me\u00f0 lokaor\u00f0um \u00deorkels \u00far greininni fr\u00e1 1926. \u00deau l\u00fdsa sennilega vi\u00f0horfum hins d\u00e6miger\u00f0a e\u00f0lisfr\u00e6\u00f0ings til afst\u00e6\u00f0iskenningarinnar fyrir um \u00fea\u00f0 bil 90 \u00e1rum:<\/p>\n<blockquote><p><em>[Afst\u00e6\u00f0iskenningin]<\/em> hefir komi\u00f0 af sta\u00f0 merkilegum tilraunum, sem \u00e1ttu a\u00f0 gera \u00fat um \u00fea\u00f0, hvort h\u00fan v\u00e6ri rjett, en \u00fe\u00f3tt margt hafi fundist, sem er eftir hennar anda og hugsun, hefir ekki enn\u00fe\u00e1 tekist a\u00f0 sanna hana, svo a\u00f0 \u00f3tv\u00edr\u0153tt sje. En margt n\u00fdtt hefir hennar vegna komi\u00f0 \u00ed lj\u00f3s.<\/p>\n<p>Enn\u00fe\u00e1 eru samt nokkrir henni fr\u00e1hverfir, og enn\u00fe\u00e1 fleiri, sem sko\u00f0a hana eigi nema h\u00e1lfan sannleika, en \u00fe\u00f3 eru \u00feeir sennilega flestir, sem hafa sannf\u00e6rst um \u00fea\u00f0, a\u00f0 h\u00fan v\u00e6ri i alla sta\u00f0i rjett. H\u00fan er or\u00f0in svo samgr\u00f3in hugsun margra, a\u00f0 \u00feeir reyna ekki a\u00f0 uppr\u00e6ta hana aftur \u00far hugsun sinni, nema kn\u00fdjandi sta\u00f0reyndir ney\u00f0i \u00fe\u00e1 til \u00feess. Fyrst ver\u00f0a tilraunirnar, sem ganga i \u00f6fuga \u00e1tt, vjefengdar, og ef ekki er h\u00e6gt a\u00f0 vjefengja \u00fe\u00e6r, \u00fe\u00e1 ver\u00f0ur reynt a\u00f0 finna n\u00fdjar lei\u00f0ir til a\u00f0 samr\u00edma afst\u00e6\u00f0iskenninguna tilraununum, ef til vill me\u00f0 \u00fevi a\u00f0 breyta einhverju \u00ed afst\u00e6\u00f0iskenningunni, en s\u00ed\u00f0ast ver\u00f0ur s\u00e1 kosturinn tekinn a\u00f0 kasta henni alveg fyrir ofurbor\u00f0. En jafnvel \u00fe\u00f3 a\u00f0 svo f\u00e6ri, hef\u00f0i h\u00fan eigi veri\u00f0 til einskis, \u00fev\u00ed a\u00f0 auk hins n\u00fdja, sem henni er a\u00f0 \u00feakka, hefir h\u00fan sett sitt m\u00f3t \u00e1 hugsun \u00feeirra v\u00edsindamanna, sem n\u00fa eru uppi, og \u00feeirra \u00e1hrifa g\u00e6tir lengi.<\/p><\/blockquote>\n<ul>\n<li>Wikipedia: <a href=\"https:\/\/en.wikipedia.org\/wiki\/Tests_of_special_relativity\">Tests of special relativity<\/a>.<\/li>\n<li>C. M. Will, 2005: <a href=\"https:\/\/pdfs.semanticscholar.org\/48b7\/fdb9b535056d7ffa987dbb2a2f310d61dea9.pdf\">Special Relativity: A Centenary Perspective<\/a>.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\u00deetta yfirlit var upphaflega birt \u00ed j\u00fan\u00ed 2019 sem hluti af f\u00e6rslu um \u00deorkel \u00deorkelsson e\u00f0lisfr\u00e6\u00f0ing (1876-1961). &nbsp; Afst\u00e6\u00f0iskenningar Einsteins Takmarka\u00f0a kenningin Einstein birti fyrstu greinar s\u00ednar um takm\u00f6rku\u00f0u afst\u00e6\u00f0iskenninguna \u00e1ri\u00f0 1905. \u00dea\u00f0 \u00e1r hefur stundum veri\u00f0 kalla\u00f0 kraftaverka\u00e1ri\u00f0, \u00fev\u00ed auk greinanna um afst\u00e6\u00f0iskenninguna birti hann t\u00edmam\u00f3tagreinar um lj\u00f3sskammta og tilvist at\u00f3ma. Einar H. Gu\u00f0mundsson, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,14,15,19],"tags":[],"class_list":["post-13581","post","type-post","status-publish","format-standard","hentry","category-edlisfraedi","category-staerdfraedi","category-stjornufraedi","category-tuttugasta-oldin"],"_links":{"self":[{"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/posts\/13581","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13581"}],"version-history":[{"count":0,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=\/wp\/v2\/posts\/13581\/revisions"}],"wp:attachment":[{"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13581"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13581"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wizardly-antonelli.176-10-35-210.plesk.page\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13581"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}