parsec
Unit used for distances to stars and galaxies. One parsec is equal to 3.2616 light years, 2.063 × 105 astronomical units, and 3.857 × 1013 km.
A parsec is the distance at which a star would have a parallax (apparent shift in position) of one second of arc when viewed from two points the same distance apart as the Earth's distance from the Sun; or the distance at which one astronomical unit subtends an angle of one second of arc.
A parsec is the distance at which a star would have a parallax (apparent shift in position) of one second of arc when viewed from two points the same distance apart as the Earth's distance from the Sun; or the distance at which one astronomical unit subtends an angle of one second of arc.
© RM 2012. Helicon Publishing is division of RM.
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