Light-minute (lmin)

AstronomicalCurrent unit

The distance light travels in a minute (about 18 million km). The Sun is roughly 8.3 light-minutes from Earth.

1 light-minute = 17,987,547,480 meters (exactly).

About the light-minute

Sunlight takes about 8.3 minutes to reach Earth, so the light-minute is the natural scale for the inner solar system. Its figure is exactly 60 light-seconds, which comes to 17,987,547,480 meters or about 18 million kilometers. The unit has no formal standing in the SI and no single inventor. It simply follows from the fixed speed of light, and it turns up in popular astronomy, in discussions of signal delays and in tables that give planetary distances as travel times.

Distance and delay are the same number in this unit, which makes it handy for spacecraft work. A signal to a distant spacecraft therefore cannot be answered instantly, because every light-minute of separation adds a minute each way. One astronomical unit is about 8.317 light-minutes, and Saturn's orbit at its closest approach to the Sun lies near 1.25 light-hours. Larger distances usually move up to light-hours or light-years.

Sources: Wikipedia: Light-minute; Wikipedia: Light-second

Light-minute conversion chart

1 light-minute expressed in every other length unit:

More Astronomical units

• astronomical unit (length)
• light-second (length)
• light-hour (length)
• light-year (length)
• parsec (length)
• megaparsec (length)
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• solar mass (weight & mass)
• Julian year (time)
• tropical year (time)
• sidereal year (time)
• synodic month (time)
• sidereal day (time)
• aeon (time)
• milliarcsecond (angle)
• zodiac sign (angle)

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