MadSci Network: Astronomy |
Dave, I can't think of any obvious deeper meaning to (1 AU)/(1 light-year). However, there is meaning in (1 AU/1 parsec), where the parsec is another unit of "local" astronomical distances (1 parsec=3.26 ly). (1 AU)/(1 parsec)=(1/206265) radians = 1 arcsecond; both radians and parsecs are measures of angle, and in fact the parsec was defined as the distance at which 1 arcsec subtends 1 AU. This has to do with the measurement of distances by parallax; see any astronomy textbook for more detail. Pauline
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