One light year is the distance that light travels in one Earth year. It is approximately equal to 9.46 e12×10¹² kilometers, or 5.88 e12×10¹² miles.

Light years are common units of measurement used in starship navigation.

When Commander Benjamin Sisko welcomed the first guest from the Gamma Quadrant in the Alpha Quadrant, a Tosk, he told him that he traveled almost ninety thousand light years through the wormhole. (DS9: "Captive Pursuit")

In 2369, a Vanoben transport was raided two light years away from Deep Space 9. (DS9: "Vortex")

The same year, Sisko told Kai Opaka that the Gamma Quadrant is seventy thousand light years away from Bajor. (DS9: "Battle Lines")

Related links Edit

• Astronomical unit
• Light hour
• Parsec

Background Edit

The exact length of a light year depends on the exact length used for one "Earth year". The IAU uses a Julian year of 365.25 days, while other sources may use a Gregorian year of 365.2425 days, or another year altogether.

Source	year (days)	light year (kilometers)	light year (miles)
IAU	365.25	9,460,730,472,581	5,878,625,373,184
Gregorian	365.2425	9,460,536,207,068	5,878,504,662,190
Google	365.242199	9.460 528 4 e12×1012	5.878 499 81 e12×1012
Yahoo	365.2411‡	9.460 5 e12×1012	5,878,482,164,161

^‡ Note that while Yahoo separately reports a year length of 365.24220 days, its rounding of the light year length to five digits works out to a year length of ~365.2411 days.

External link Edit

• Light-year at Wikipedia