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| − | '''AU''' is the abbreviation for '''astronomical unit''', a unit of linear measure based on the mean distance of [[Earth-That-Was]] to its Sun—some 93,954,524.4 miles—and a unit best used for intrasystem ranging. It is commonly superseded for use at interstellar and intragalactic scales by the more accommodating [[light year]] and [[parsec]], and by [[Kiloparsec|kilo]]- and [[megaparsec]] at [[Local Group]] or other intergalactic distances. |
+ | '''AU''' is the abbreviation for '''astronomical unit''', a unit of linear measure based on the mean distance of [[Earth-That-Was]] to its Sun—some 93,954,524.4 miles—and a unit best used for intrasystem ranging. It is commonly superseded for use at interstellar and intragalactic scales by the more accommodating [[light year]] and [[parsec]], and by [[Kiloparsec|kilo]]- and [[megaparsec]] at [[Local Group]] or other intergalactic distances. |
Since about 62,399 AU make a light year, and 3.26ly a parsec, astronomers primarily use the former unit to measure the smaller distances between planets within a system (or between a star and its retinue), and use the latter two units for measuring the far larger distances among and between stars within a galaxy. |
Since about 62,399 AU make a light year, and 3.26ly a parsec, astronomers primarily use the former unit to measure the smaller distances between planets within a system (or between a star and its retinue), and use the latter two units for measuring the far larger distances among and between stars within a galaxy. |
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| − | [[Category:Real world]] |
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[[Category:Spatial Distance]] |
[[Category:Spatial Distance]] |
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Revision as of 01:34, 23 September 2012
AU is the abbreviation for astronomical unit, a unit of linear measure based on the mean distance of Earth-That-Was to its Sun—some 93,954,524.4 miles—and a unit best used for intrasystem ranging. It is commonly superseded for use at interstellar and intragalactic scales by the more accommodating light year and parsec, and by kilo- and megaparsec at Local Group or other intergalactic distances.
Since about 62,399 AU make a light year, and 3.26ly a parsec, astronomers primarily use the former unit to measure the smaller distances between planets within a system (or between a star and its retinue), and use the latter two units for measuring the far larger distances among and between stars within a galaxy.