Light second

The light second is the distance that the light travels in vacuum in one second and so is a unit of distance.

Similar units are the light minute, light hour, light day, light week, light month, light year. A light minute is 60 light seconds and a light hour is 60 light minutes, or 3600 light seconds.

numerical value

As opposed to the light year, whose value more or less depends on the definition of year, the value of the light second is defined exactly.

• velocity of light in vacuum: 2.99792456 * 10⁸ m/s (meters/second)
• 1 light second = 2.99792456 * 10⁸m

Comparison to other Units

• 1 AU = 499 light seconds
• 1 light second = 299,792.456 km
• 1 light second = 186,282.3958 mi
• 1 light second = 983,571,049.9 ft
• 1 light second = 327,857,016.6 yd

Distances in Light Seconds

• the average distance between earth and moon is about 1.3 light seconds
• the average distance between earth and sun is about 499 light seconds or 8.3 light minutes