Light-seconds to Yards (ls to yd)

1 light-second equals 327,857,018.8 yards (rounded).

1 light-second = 327,857,018.8 yards

How to convert light-seconds to yards

To convert light-seconds to yards, multiply the number of light-seconds by 327,857,018.8. The factor is rounded to 10 significant digits. To go the other way, multiply yards by 3.050110086×10⁻⁹ (rounded).

yards = light-seconds × 327,857,018.8

Example: 10 light-seconds = 3,278,570,188 yards.

About these units

Light-second (ls)

AstronomicalCurrent unit

The distance light travels in a vacuum in one second: 299,792,458 meters. The Moon is about 1.28 light-seconds from Earth.

Because the speed of light is now fixed at 299,792,458 meters per second, a light-second is exactly that many meters, with no uncertainty at all. Astronomers and radio engineers treat it as a convenient yardstick for distances that are small on the scale of the solar system but large on the scale of a laboratory. The abbreviation ls appears in tables of astronomical units, and it is not an official SI unit.

The Moon is the standard example: its average distance from Earth is about 1.282 light-seconds, which is why a radio exchange with a lunar mission has a noticeable round-trip lag of roughly two and a half seconds. The Earth's mean diameter is only about 0.0425 light-seconds, while the Sun's diameter is about 4.643. One astronomical unit is about 499 light-seconds. Sixty light-seconds make a light-minute, 3,600 make a light-hour, and 31,557,600 make a light-year, based on the Julian year.

1 light-second = 299,792,458 meters (exactly).

Sources: Wikipedia: Light-second; Wikipedia: Light-minute

Yard (yd)

US & ImperialCurrent unit

3 feet or 36 inches, exactly 0.9144 meters. Used for sports fields, fabric and short distances in the US and UK.

Yard descends from the Old English gerd or gyrd, meaning a branch, stave or measuring rod. It first appears in the late seventh-century laws of Ine of Wessex, though there it names a tax unit, the yardland. Around 959 to 963 King Edgar ordered that the measure held at Winchester be used throughout his realm, the earliest record of a prototype. A story that Henry I fixed the yard as the distance from his nose to his thumb is later folklore, and the true origin, whether pace, cubit or waist, remains speculative.

Britain defined the Imperial Standard Yard in 1824 as the distance between two marks on a brass rod at 62 degrees Fahrenheit. A fire in 1834 damaged the standard, a replacement was made in 1845, and the Weights and Measures Act 1855 recognized it. The 1959 international agreement then fixed the yard at exactly 0.9144 meter. Today it measures American and Canadian football fields, association football pitches and cricket pitches, appears on UK road signs for short distances, and is still used to sell fabric in the US and UK.

1 yard = 0.9144 meters (exactly).

Sources: Wikipedia: Yard; Wikipedia: Inch; NIST Guide to the SI, Appendix B.8: conversion factors

Related conversions

See all length units.