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From Citizendium, the Citizens' Compendium

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

Similar units are the light second, light minute, light hour, light week, light month, light year.

Contents 1 numerical value 2 Comparison to other Units 3 Distances in Light days 4 Notes

numerical value

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

• velocity of light in vacuum: 299,792,458 m/s ^[1] (meters/second)
• 1 day = 24 hour = 1440 minutes = 86400 seconds
• 1 light day = 25,902,068,371,200 m = 2.5902067 * 10¹³m

Comparison to other Units

• 1 light day = 25,902,068,371.200 km = 2.5902068 * 10¹⁰ km
• 1 light day = 16,094,799,105.225 mi^[2] = 1.6094799 * 10¹⁰ mi
• 1 light day = 84,980,539,275,590.551 ft^[3] = 8.4980539¹³ ft
• 1 light day = 28,326,846,425,196.850 yd ^[4] = 2.8326846 * 10¹³ yd

Distances in Light days

• the maximum distance between sun and Sedna^[5] is about 133,593 Mio km or 5.1 light days

Notes