Astronomska jedinica

Astronomska jedinica (hrvatska kratica AJ ili aj, međunarodna kratica od eng. AU, skraćeno od Astronomical Unit) jest mjerna jedinica za duljinu. Međunarodni ured za mjere i utege predlaže oznaku za astronomsku jedinicu ua.^[1]

Upotrebljava se u astronomiji i približno je jednaka prosječnoj udaljenosti Zemlje od Sunca, odnosno velikoj poluosi Zemljine orbite. Trenutno prihvaćena vrijednost te udaljenosti jednaka je 149 597 870 691 ± 30 metara (približno 150 milijuna kilometara).^[1] Do 2012. astronomska jedinica bila je definirana u okviru Zemljine orbite, ali odonda se definira kao točno 149 597 870 700 metara.^[2]

Izvori

↑ ^a ^b The International System of Units (SI), 8. izdanje, 2006, strana 126
↑ RESOLUTION B2 on the re-definition of the astronomical unit of length (PDF). International Astronomical Union. Beijing. 31. kolovoza 2012. The XXVIII General Assembly of International Astronomical Union recommends [adopted] that the astronomical unit be re-defined to be a conventional unit of length equal to exactly 149,597,870,700 metres, in agreement with the value adopted in IAU 2009 Resolution B2

[The_International_System_of_Units-1] The International System of Units (SI), 8. izdanje, 2006, strana 126

[2] RESOLUTION B2 on the re-definition of the astronomical unit of length (PDF). International Astronomical Union. Beijing. 31. kolovoza 2012. The XXVIII General Assembly of International Astronomical Union recommends [adopted] that the astronomical unit be re-defined to be a conventional unit of length equal to exactly 149,597,870,700 metres, in agreement with the value adopted in IAU 2009 Resolution B2

[1]

[2]