An astronomical unit (AU) is equal to the average distance from Earth to the Sun, about 92.9 x 106 mi. A parsec (pc) is the distance at which a length of 1 AU would subtend an angle of exactly 1 second of arc (Fig. 1-8). A light-year (1y) is the distance that light, traveling through a vacuum with a speed of 186 000 mi/s, would cover in 1.0 year. Express the Earth-Sun distance in(a) Parsecs and(b)Light-years.

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1 pc 1 pc An angle of exactly 1 second -I AU