Light-hours to Inches (lh to in)

1 light-hour equals 42,490,269,637,795 inches (rounded).

1 light-hour = 42,490,269,637,795 inches

How to convert light-hours to inches

To convert light-hours to inches, multiply the number of light-hours by 42,490,269,637,795. The factor is rounded to 10 significant digits. To go the other way, multiply inches by 2.353480005×10⁻¹⁴ (rounded).

inches = light-hours × 42,490,269,637,795

Example: 10 light-hours = 424,902,696,377,953 inches.

About these units

Light-hour (lh)

AstronomicalCurrent unit

The distance light travels in an hour (about 1.08 billion km). Pluto is about 4.8 light-hours from the Sun.

Reaching the outer planets takes light hours rather than minutes, and the light-hour is the matching unit. Equal to 3,600 light-seconds, it is exactly 1,079,252,848,800 meters, or about 1.08 billion kilometers. Like the other light-time units it is informal, defined entirely by the fixed speed of light and the length of the SI second rather than by any standards body, and it appears mainly in astronomy outreach and in descriptions of deep-space missions.

Neptune orbits at about 30 astronomical units, which with light taking roughly 499 seconds per unit works out to somewhat over four light-hours. Pluto, at an average of 34.72 astronomical units, is about 4.81 light-hours from the Sun. The Voyager 1 probe passed 23 light-hours from Earth and the Sun by 2025 and is expected to reach one light-day, 24 light-hours, around late 2026. Beyond that scale the light-day, light-week and light-year take over.

1 light-hour = 1,079,252,848,800 meters (exactly).

Sources: Wikipedia: Light-hour; Wikipedia: Light-minute; Wikipedia: Astronomical unit

Inch (in)

US & ImperialCurrent unit

1/12 of a foot. Defined as exactly 25.4 millimeters since 1959, when the US and Commonwealth countries agreed a common international inch.

Latin uncia, meaning one-twelfth, is the root of both inch and ounce, and it passed into Old English as ynce. Roman measurers divided their foot into twelve unciae, and the English inch kept that twelfth. After 1066 an inch was reckoned as three barleycorns, and a 1324 statute attributed to Edward II spelled out the definition as three grains of barley, dry and round, placed end to end lengthwise. For centuries the inch was simply a twelfth of a foot, or a thirty-sixth of a yard, and the US and UK each kept their own copy of the standard yard.

Those copies differed slightly until the 1959 international agreement fixed the yard at exactly 0.9144 meter, which made the inch exactly 25.4 millimeters. The US adopted it in 1959 and the UK ratified it in 1963, effective 1964. Today the inch is still the customary unit in the United States and Canada, and the UK keeps it on road signs. Worldwide it also names display diagonals, wheel rims, tire codes and pipe sizes.

1 inch = 0.0254 meters (exactly).

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

Related conversions

See all length units.