{"id":465,"date":"2017-09-20T20:33:40","date_gmt":"2017-09-20T20:33:40","guid":{"rendered":"http:\/\/80.85.86.254\/sjor\/?p=465"},"modified":"2020-10-21T14:24:58","modified_gmt":"2020-10-21T14:24:58","slug":"3-2-lofthjupurinn","status":"publish","type":"post","link":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/2017\/09\/20\/3-2-lofthjupurinn\/","title":{"rendered":"3.2 Lofthj\u00fapurinn"},"content":{"rendered":"

Merk\u00far, s\u00fa reikistjarna sem er n\u00e6st s\u00f3linni, hefur n\u00e1nast engan lofthj\u00fap. N\u00e6star koma reikistj\u00f6rnurnar Venus, J\u00f6r\u00f0in og Mars. \u00de\u00e6r lofttegundir (a\u00f0allega vetni, hel\u00edum og metan) sem voru til sta\u00f0ar \u00feegar stj\u00f6rnurnar myndu\u00f0ust hafa allar horfi\u00f0 \u00fat \u00ed geiminn. Lofthj\u00fapurinn sem n\u00fa umkringir \u00feessar reikistj\u00f6rnur samanstendur annars vegar af lofttegundum og agna\u00fa\u00f0a \u00far i\u00f0rum stjarnanna (t.d. fr\u00e1 eldgosum) og hins vegar af lofttegundum og agna\u00fa\u00f0a fr\u00e1 efnahv\u00f6rfum fyrrnefndu lofttegundanna. L\u00edfefnafr\u00e6\u00f0ilegir ferlar (og \u00fe\u00e1 s\u00e9rstaklega lj\u00f3still\u00edfun) hafa l\u00edka haft mikil \u00e1hrif \u00e1 samsetningu lofthj\u00faps jar\u00f0ar.<\/p>\n

\"\"<\/a>

Mynd 3.2. S\u00f3lin og reikistj\u00f6rnurnar (Merk\u00far, Venus, J\u00f6r\u00f0in og tungli\u00f0, Mars, J\u00fap\u00edter, Sat\u00farnus, \u00daranus, Nept\u00fanus).<\/p><\/div>\n

Lofthj\u00fapur jar\u00f0arinnar er \u00ed raun \u00feunnt lag lofttegunda sem umlykur hn\u00f6ttinn, reyndar mj\u00f6g \u00feunnt mi\u00f0a\u00f0 vi\u00f0 st\u00e6r\u00f0 jar\u00f0arinnar. \u00deykkt lofthj\u00fapsins er \u00feannig ekki nema um 100 km e\u00f0a 0,15% af \u00feverm\u00e1li jar\u00f0ar. \u00deetta \u00feunna lag, me\u00f0 s\u00edna einst\u00f6ku efnasamsetningu, er \u00fe\u00f3 gr\u00ed\u00f0arlega mikilv\u00e6gt. Lofthj\u00fapurinn ver okkur gegn h\u00e6ttulegri geislun fr\u00e1 s\u00f3linni og heldur hitastigi \u00e1 j\u00f6r\u00f0inni \u00ed jafnv\u00e6gi. Lofttegundir \u00e1 bor\u00f0 vi\u00f0 s\u00farefni og kold\u00edox\u00ed\u00f0 sty\u00f0ja vi\u00f0 \u00fe\u00e1 ferla sem allt l\u00edf byggist \u00e1. \u00cd t\u00f6flu 3.1 m\u00e1 sj\u00e1 hlutfallslegt magn algengustu lofttegundanna \u00ed lofthj\u00fapnum \u00ed \u00feurru lofti. Hlutfall vatnsgufu \u00ed lofthj\u00fapnum sveiflast fr\u00e1 um 0,5-3,5% og er breytilegt \u00ed t\u00edma og r\u00fami. A\u00f0 me\u00f0altali er hlutfall vatnsgufu 1% vi\u00f0 yfirbor\u00f0 jar\u00f0ar en 0,4% a\u00f0 me\u00f0altali \u00ed \u00f6llum lofthj\u00fapnum. \u00deegar magn lofttegunda er mj\u00f6g l\u00edti\u00f0 er \u00fea\u00f0 oft gefi\u00f0 upp \u00ed millj\u00f3nustuhlutum e\u00f0a ppm (e. parts per million). Magn kold\u00edox\u00ed\u00f0s er t.d. um 0,04% sem samsvarar 400 ppm.<\/p>\nTafla 3.1. Hlutfall lofttegunda \u00ed lofthj\u00fapnum mi\u00f0a\u00f0 vi\u00f0 r\u00famm\u00e1l af \u00feurru lofti. <\/span>\n\n\n\n\n\t\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t
Lofttegund<\/th>Hlutfall<\/th>\n<\/tr>\n<\/thead>\n
K\u00f6fnunarefni (N2<\/sub>)<\/td>78,10%<\/td>\n<\/tr>\n
S\u00farefni (O2<\/sub>) <\/td>20,93%<\/td>\n<\/tr>\n
Argon (Ar)<\/td>0,93%<\/td>\n<\/tr>\n
Kold\u00edox\u00ed\u00f0 (CO2<\/sub>)<\/td>0,04%<\/td>\n<\/tr>\n
Neon (Ne)<\/td>18 ppm<\/td>\n<\/tr>\n
Hel\u00edum (He)<\/td>5 ppm<\/td>\n<\/tr>\n
Metan (CH4<\/sub>)<\/td>1,8 ppm<\/td>\n<\/tr>\n
Vetni (H2<\/sub>)<\/td>0,5 ppm<\/td>\n<\/tr>\n
Gla\u00f0loft (N2<\/sub>O)<\/td>0,3 ppm<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n","protected":false},"excerpt":{"rendered":"

Merk\u00far, s\u00fa reikistjarna sem er n\u00e6st s\u00f3linni, hefur n\u00e1nast engan lofthj\u00fap. N\u00e6star koma reikistj\u00f6rnurnar Venus, J\u00f6r\u00f0in og Mars. \u00de\u00e6r lofttegundir (a\u00f0allega vetni, hel\u00edum og metan) sem voru til sta\u00f0ar \u00feegar stj\u00f6rnurnar myndu\u00f0ust hafa allar horfi\u00f0 \u00fat \u00ed geiminn. Lofthj\u00fapurinn sem Lesa meira…<\/a><\/p>\n","protected":false},"author":2,"featured_media":1014,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[],"class_list":["post-465","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-03-loftslagsbreytingarogsurnunsjavar"],"_links":{"self":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts\/465","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/comments?post=465"}],"version-history":[{"count":25,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts\/465\/revisions"}],"predecessor-version":[{"id":3371,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/posts\/465\/revisions\/3371"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/media\/1014"}],"wp:attachment":[{"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/media?parent=465"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/categories?post=465"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/himinnoghaf.is\/mengunsjavar\/index.php\/wp-json\/wp\/v2\/tags?post=465"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}