Meters to Light-hours (m to lh)
1 meter equals 9.265669311×10⁻¹³ light-hours (rounded).
How to convert meters to light-hours
To convert meters to light-hours, multiply the number of meters by 9.265669311×10⁻¹³. The factor is rounded to 10 significant digits. To go the other way, multiply light-hours by 1,079,252,848,800.
light-hours = meters × 9.265669311×10⁻¹³
Example: 10 meters = 9.265669311×10⁻¹² light-hours.
About these units
Meter (m)
The SI base unit of length. Since 1983 it is defined as the distance light travels in a vacuum in 1/299,792,458 of a second.
Meter comes from the Greek metron, a measure. In 1791 the French National Assembly defined it as one ten-millionth of the distance from the equator to the North Pole along a great circle through Paris, after rejecting the length of a seconds pendulum because that length changes with local gravity. The surveyors Delambre and Méchain measured the meridian arc, and in 1799 a platinum bar known as the Mètre des Archives became the physical standard. NIST notes that this Earth-based meter turned out to be about 0.2 mm shorter than the true pole-to-equator fraction it was meant to represent.
The 1875 Treaty of the Meter created the CGPM and the BIPM to look after common standards, and in 1889 a platinum-iridium prototype bar took over; the original is still kept at the BIPM. In 1960 the meter was tied to 1,650,763.73 wavelengths of an orange-red krypton-86 line, and in 1983 to the speed of light, which made length a quantity derived from the time standard. The 2018 revision reworded that definition without changing the meter's size. NIST offers a handy yardstick for scale: a pace, meaning two steps, is roughly a meter or a yard.
The meter is the reference unit for length on this site.
Sources: BIPM: history of the metre; NIST: the meter and the SI redefinition; Wikipedia: Metre
Light-hour (lh)
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
Related conversions
- Light-hours to meters (reverse)
- Meters to kilometers
- Meters to centimeters
- Meters to millimeters
- Meters to inches
- Meters to feet
- Meters to yards
- Meters to miles
- Meters to micrometers
- Meters to nanometers
- Meters to nautical miles
- Meters to pixels (CSS)
- Meters to light-years
- Kilometers to light-hours
- Centimeters to light-hours
- Millimeters to light-hours
- Inches to light-hours
- Feet to light-hours
- Yards to light-hours
- Miles to light-hours
See all length units.