Miles to Light-years (mi to ly)
1 mile equals 1.70107795×10⁻¹³ light-years (rounded).
How to convert miles to light-years
To convert miles to light-years, multiply the number of miles by 1.70107795×10⁻¹³. The factor is rounded to 10 significant digits. To go the other way, multiply light-years by 5,878,625,373,184 (rounded).
light-years = miles × 1.70107795×10⁻¹³
Example: 10 miles = 1.70107795×10⁻¹² light-years.
About these units
Mile (mi)
5,280 feet or 1,760 yards, exactly 1,609.344 meters. This is the statute (international) mile used on US and UK roads.
A thousand paces gave the mile its name. It descends from the Latin mille passus, the Roman mile, by way of Old English mil and Middle English myle. For centuries after Rome, miles of many lengths coexisted; a sixteenth-century Mercator map, for example, shows small, medium and large Flemish miles on a single scale bar. The English statute mile was fixed by an Act of Parliament under Elizabeth I in 1593, which declared that a mile contains eight furlongs, or 5,280 feet.
The 1959 international yard and pound agreement made that mile exactly 1,609.344 meters. A slightly longer US survey mile, about 1,609.347 meters, lingered in American land surveys and was slated for retirement from 1 January 2023. Today the mile is the road unit of the United Kingdom, the United States, Liberia and Myanmar, along with several territories such as the Bahamas, Belize, Guam and the US Virgin Islands. In Canada it survives chiefly in rail transport and horse racing.
1 mile = 1,609.344 meters (exactly).
Sources: Wikipedia: Mile; Wikipedia: Foot (unit); NIST Guide to the SI, Appendix B.8: conversion factors
Light-year (ly)
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
Related conversions
- Light-years to miles (reverse)
- Miles to meters
- Miles to kilometers
- Miles to centimeters
- Miles to millimeters
- Miles to inches
- Miles to feet
- Miles to yards
- Miles to micrometers
- Miles to nanometers
- Miles to nautical miles
- Miles to pixels (CSS)
- Miles to picometers
- Meters to light-years
- Kilometers to light-years
- Centimeters to light-years
- Millimeters to light-years
- Inches to light-years
- Feet to light-years
- Yards to light-years
- Micrometers to light-years
- Nanometers to light-years
- Nautical miles to light-years
- Pixels (CSS) to light-years
See all length units.