Bruger:Metalindustrien/Kasse1: Forskelle mellem versioner

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[[File:seasons.svg|frame|right|Jordens [[aksehældning]] flugter med indgående [[sollys]] omkring [[vintersolhverv]] på den [[nordlige halvkugle]]. Uafhængigt af tidspunkt på dagen (dvs. uafhængigt af [[Jordens rotation]] om sin akse) så vil [[Sydpolen]] på dette tidspunkt være oplyst mens [[Nordpolen]] vil være mørk og opleve såkaldt [[polarnat]].]]
 
TheÅrstiderne seasonser resultforårsaget fromaf thedet Earth'sfaktum at Jordens [[axis of rotationaksehældning]] beinger [[axial tilt#EarthRotationsmekanik|tiltedvippet]] withomkring respect to its23,4 [[orbital plane (astronomy)|orbital planegrad]]er byift. an angle of approximately 23.4sit [[degree (angle)|degreesbaneplan]].<ref>{{cite web|last=Cain|first=Fraiser|title=Tilt of the Earth|url=http://www.universetoday.com/26778/tilt-of-the-earth/|access-date=2 May 2014}}</ref> (ThisDette tiltkendes isogså also known assom "obliquityskråningen of theaf [[eclipticekliptika]]".)
 
Regardless of the time of year, the [[Northern Hemisphere|northern]] and [[southern hemisphere]]s always experience opposite seasons. This is because during [[summer]] or [[winter]], one part of the planet is more directly exposed to the rays of the Sun than the other, and this exposure alternates as the Earth revolves in its orbit. For approximately half of the year (from around March{{nbsp}}20 to around September{{nbsp}}22), the Northern Hemisphere tips toward the Sun, with the maximum amount occurring on about June{{nbsp}}21. For the other half of the year, the same happens, but in the Southern Hemisphere instead of the Northern, with the maximum around December{{nbsp}}21. The two instants when the Sun is directly overhead at the [[Equator]] are the [[equinox]]es. Also at that moment, both the [[North Pole]] and the [[South Pole]] of the Earth are just on the [[terminator (solar)|terminator]], and hence day and night are equally divided between the two hemispheres. Around the [[March equinox]], the Northern Hemisphere will be experiencing [[Spring (season)|spring]] as the hours of [[daylight]] increase, and the Southern Hemisphere is experiencing [[autumn]] as daylight hours shorten.