One light year is the distance that light travels in one Earth year. It is approximately equal to 9.46 ×1015 meters, or 5.88 ×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 travelled almost ninetythousand 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")
Related links
Background
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 (meters) | light year (miles) |
|---|---|---|---|
| IAU | 365.25 | 9,460,730,472,580,800 | 5,878,625,373,184 |
| Gregorian | 365.2425 | 9,460,536,207,068,020 | 5,878,504,662,190 |
| 365.242199 | 9.460 528 4 ×1015 | 5.878 499 81 ×1012 | |
| Yahoo | 365.2411‡ | 9.460 5 ×1015 | 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.