Earth's rotation: Difference between revisions

Earth rotates once in about 24 hours with respect to the [[Sun]], but once every 23 hours, 56 minutes and 4 seconds with respect to other distant stars ([[#Stellar and sidereal day|see below]]). Earth's rotation is slowing slightly with time; thus, a day was shorterlonger in the past. This is due to the [[tidal acceleration|tidal effects]] the [[Moon]] has on Earth's rotation. [[Atomic clock]]s show that the modern day is longer by about 1.7 [[millisecond]]s than a century ago,<ref name="McCarthySeidelmann2009">{{cite book|author1=Dennis D. McCarthy|author2=Kenneth P. Seidelmann|title=Time: From Earth Rotation to Atomic Physics|url=https://books.google.com/books?id=fjFVW3-LGigC|date=18 September 2009|publisher=John Wiley & Sons|isbn=978-3-527-62795-0|page=232}}</ref> slowly increasing the rate at which [[Coordinated Universal Time|UTC]] is adjusted by [[leap second]]s. Analysis of historical astronomical records shows a slowing trend; the [[Day length fluctuations|length of a day]] increased by about 2.3 milliseconds per century since the [[8th century BC|8th century BCE]].<ref>{{cite journal |last=Stephenson |first=F. Richard |title=Historical eclipses and Earth's rotation |journal=Astronomy & Geophysics |year=2003 |volume=44 |number=2 |pages=2.22–2.27 |doi=10.1046/j.1468-4004.2003.44222.x |bibcode=2003A&G....44b..22S |doi-access=free }}</ref>