Just for information, 1 light-year is equivalent to the distance travelled by light in 1 year moving in a vacuum. 1 light-year is about 9.4607 * 10^{15} metres.
1 astronomical unit (AU) is equivalent to the average radius of the Earth's orbit. 1 AU is about 1.4960 * 10^{11} metres.
Simple arithmetic calculation yields the answer that 1 light-year = 63240 AU to a good approximation.
Answered by:
Ryan Leong, Undergraduate, NUS, Singapore
'To myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.'