An astronomical unit (AU) is equal to the average distance from the Earth to the sun, about 92.9 106 mi. A parsec (pc) is the distance at which 1 AU would subtend an angle of 1 second of arc. How many miles are there in a parsec?
What will be an ideal response?
Question 2
Kepler's discovery that T2 /r3 = K applies
A) to orbits where K is a universal constant.
B) only to circular orbits.
C) to lunar motion provided K is the same for planetary motion.
D) to elliptical orbits where r is the average distance.