Previous Page...   Printer Version Science Constants - Année-lumière Symbol: ly Value: 9.46052973 × 1015 m Category: - Units of Length Description: The light year is defined as the distance travelled by electromagnetic radiation in one tropical year. Used in astronomy.   [ H O M E ] [ S C I E N C E ] [ M A T H S ] [ A S T R O N O M Y ] [ Download ] [ Shop ] [ Contact ] [ About ]