Light-years to Nautical Miles (ly to nmi)

1 light-year equals 5,108,385,784,331 nautical miles (rounded).

1 light-year = 5,108,385,784,331 nautical miles

How to convert light-years to nautical miles

To convert light-years to nautical miles, multiply the number of light-years by 5,108,385,784,331. The factor is rounded to 10 significant digits. To go the other way, multiply nautical miles by 1.957565545×10⁻¹³ (rounded).

nautical miles = light-years × 5,108,385,784,331

Example: 10 light-years = 51,083,857,843,309 nautical miles.

About these units

Light-year (ly)

AstronomicalCurrent unit

The distance light travels in one Julian year: exactly 9,460,730,472,580,800 meters (about 9.46 trillion km).

Despite the name, a light-year measures distance rather than time, and its coinage is a little later than most people assume. Friedrich Bessel measured the distance to the star 61 Cygni in 1838 but did not use the unit himself. The light-year appeared in print in 1851, in a German article by Otto Ule, who explained its odd use of a time word by comparing it to saying that a place is an hour's walk away.

The International Astronomical Union defines it as the distance light travels in a vacuum in one Julian year of 365.25 days, about 9.46 trillion kilometers. NIST lists it as 9.460 73 times 10 to the 15th meters. Light-years dominate popular science, while professional astronomers mostly prefer the parsec, about 3.26 light-years. For scale, Proxima Centauri, the nearest star to the Sun, is about 4.24 light-years away, and the Milky Way is roughly 100,000 light-years across.

1 light-year = 9.460730473×10¹⁵ meters (approximately).

Sources: Wikipedia: Light-year; NIST Guide to the SI, Appendix B.8: conversion factors

Nautical Mile (nmi)

NauticalCurrent unit

Exactly 1,852 meters, close to one minute of latitude. The standard unit of distance at sea and in aviation; one nautical mile per hour is one knot.

Sailors wanted a distance that matched their charts, so the nautical mile was tied to the globe itself: one minute of arc, one sixtieth of a degree, of latitude. Earth's polar circumference is therefore close to 21,600 nautical miles. Because Earth is flattened at the poles, a minute of latitude is about 1,843 meters at the equator and about 1,862 at the poles, so the fixed value of 1,852 meters is a compromise. France's definition of the meter produced a figure near 1,851.85 meters, which helped set the number.

The First International Extraordinary Hydrographic Conference in Monaco defined the international nautical mile as exactly 1,852 meters in 1929. The United States kept its own variant until 1954, and the United Kingdom adopted the international value in 1970. A speed of one nautical mile per hour is one knot. The unit is not part of SI but remains the norm in air, marine and space navigation and in defining territorial waters, because distances on a chart can be read straight off the latitude scale. Its symbols vary: NM, nmi and M all appear.

1 nautical mile = 1,852 meters (exactly).

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

Related conversions

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