July 5, 2012 - Earth at Aphelion

nInnthe wintertime for me and billions of other Northern-Hemispherentypes, the Earth was at its closest to the Sun (even though it wasnpretty much the coldest part of the year, for us). Now that thenNorthern Hemisphere is broiling under a summer Sun, we find out thatnEarth is at its farthest point from the Sun.

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Thenfarthest point of an elliptical (oval-shaped) orbit is callednaphelion. And the Earth reached this point today at 3:33 UTC.n(UTC means “Universal Time Coordinated.” It represents the timenin Greenwich, England, which is seven hours later than my time innCalifornia, with Daylight Savings Time.) n

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nSincenthe Earth’s orbit is almost a circle, the difference between itsnaphelion (furthest point) and its perihelion (closest point) is verynsmall (compared to the size of the orbit, that is!). There is only 3%ndifference between Earth’s aphelion and perihelion. Earth’s seasonsnand climate have nothing to do with this small difference in distancento the Sun. Instead, they are related to the tilt of the Earth on itsnaxis and the resulting change in angle of the Sun’s warmingnradiation.

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nSomensolar system denizens have much more elliptical orbits. Pluto’s orbitnaround the Sun is much less circular than Earth’s, for example, andnHalley’s comet “circles” the sun in a really long, skinny oval. n

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Findnout more about elliptical orbits at Windows to the Universe. Be surento click the various links—for example, don’t miss the interactive animation!

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nAlsonon this date:

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