Centimeters to Light-years (cm to ly)

1 centimeter equals 1.057000834×10⁻¹⁸ light-years (rounded).

1 centimeter = 1.057000834×10⁻¹⁸ light-years

How to convert centimeters to light-years

To convert centimeters to light-years, multiply the number of centimeters by 1.057000834×10⁻¹⁸. The factor is rounded to 10 significant digits. To go the other way, multiply light-years by 9.460730473×10¹⁷ (rounded).

light-years = centimeters × 1.057000834×10⁻¹⁸

Example: 10 centimeters = 1.057000834×10⁻¹⁷ light-years.

About these units

Centimeter (cm)

Metric (SI)Current unit

One hundredth of a meter. Used for body measurements, clothing and everyday objects.

Scientists, rather than shopkeepers, gave the centimeter its place. In 1832 Carl Friedrich Gauss proposed a system of absolute units built on length, mass and time, choosing the millimeter, milligram and second. In 1873 a committee of the British Association for the Advancement of Science, whose members included James Clerk Maxwell and William Thomson (Lord Kelvin), recommended the centimeter, gram and second instead. That CGS system dominated physics for decades, until the metre-kilogram-second system replaced it in the mid-twentieth century and led to SI.

CGS units proved awkward for rooms and buildings, which run to hundreds of centimeters, but the centimeter itself never went away. It is still the everyday unit for height, clothing and small objects, and it appears in map scales and rainfall reports. An adult fingernail is roughly one centimeter wide, and a milliliter is defined as exactly one cubic centimeter. An inch is exactly 2.54 centimeters. The CGS system itself survives mainly in theoretical physics and astrophysics, where Gaussian units are still common.

1 centimeter = 0.01 meters (exactly).

Sources: Wikipedia: Centimetre-gram-second system of units; Wikipedia: Centimetre; NIST Guide to the SI, Appendix B.8: conversion factors

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

Related conversions

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