Units of distance (or length) vary depending on the measurement system being used and the scale of the distance being measured. Here are the common units of distance:
1. Metric (SI) System:
- Millimeter (mm): 1 mm = 10−310^{-3}10−3 meters
- Centimeter (cm): 1 cm = 10−210^{-2}10−2 meters
- Meter (m): Base unit of length in the SI system
- Kilometer (km): 1 km = 1,000 meters
- Megameter (Mm): 1 Mm = 1,000,000 meters
- Gigameter (Gm): 1 Gm = 1,000,000,000 meters
- Terameter (Tm): 1 Tm = 1,000,000,000,000 meters
2. Imperial (British) System:
- Inch (in): 1 inch = 1/12 feet = 2.54 cm
- Foot (ft): 1 foot = 12 inches = 0.3048 meters
- Yard (yd): 1 yard = 3 feet = 0.9144 meters
- Mile (mi): 1 mile = 1,760 yards = 1,609.344 meters
- Furlong: 1 furlong = 220 yards = 201.168 meters
3. Astronomical Units (for large distances):
- Astronomical Unit (AU): 1 AU = approximately 149.6 million kilometers (distance from Earth to Sun)
- Light Year (ly): 1 light year = the distance light travels in one year, about 9.461 trillion kilometers
- Parsec (pc): 1 parsec = approximately 3.26 light years or about 3.09 × 101310^{13}1013 kilometers
4. Nautical Units (used in navigation):
- Nautical Mile (nm): 1 nautical mile = 1,852 meters (about 1.15078 miles)
5. Other Units:
- Angstrom (Å): 1 Å = 10−1010^{-10}10−10 meters (used to measure atomic and molecular scales)
- Fermi (fm): 1 fm = 10−1510^{-15}10−15 meters (used in nuclear physics)
- Light-second (ls): The distance that light travels in one second, approximately 299,792 kilometers (186,282 miles)
Each unit is used based on the scale of measurement, from the smallest (like Angstroms for atomic scales) to large astronomical distances like light years or parsecs.
