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TheEarth’scircularmotionisitsmovementaroundtheSuninanelliptical
orbit,inacounterclockwisedirection.
ThedaywhentheEarthisclosesttoourstar–about147millionkilometres
fromit–fallseveryyearbetweenthe2ndand5thofJanuary,andisreferred
toasperihelion.Inturn,thedayfallingbetweenthe3rdand7thofJuly,
whenthedistancebetweenourplanetandtheSunisatitsgreatest,at152
millionkilometres,iscalledaphelion.
TomakeafullrevolutionaroundtheSun,theEarthneedsexactly365days,
5hours,48minutesand46seconds–thelengthofonefullsolaryear,during
whichtheEarthtravelsanincredible939887974kilometres.
Theconsequencesofthecircularmotionincludefourconventionaltime
periods,followingeachotherinanunchangingorder,calledseasons.Each
oneofthemischaracterisedbyitsownthresholdtemperatures,aswell
asvariationsinthedurationofdayandnight.
Itissaidthatthephenomenonoftheseasonsislinkedtothehumanmood
throughthevaryinglengthofsunlightduringtheday,andthereforethe
amountofdaylightthatweexperienceourbrainsinparticularmonths.
