How many astronomical units are in a light year?

Asked by: Justin Dopiriak


A good approximation would be:

1 light-year = 63240 AU (astronomical units)

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 * 1015 metres.

1 astronomical unit (AU) is equivalent to the average radius of the Earth's orbit. 1 AU is about 1.4960 * 1011 metres.

Simple arithmetic calculation yields the answer that 1 light-year = 63240 AU to a good approximation.

Answered by: Ryan Leong, Undergraduate, NUS, Singapore



Science Quote

'In a way science is a key to the gates of heaven, and the same key opens the gates of hell, and we do not have any instructions as to which is which gate. Shall we throw away the key and never have a way to enter the gates of heaven? Or shall we struggle with the problem of which is the best way to use the key?'

Richard Phillips Feynman