|This article does not cite any sources. (December 2009) (Learn how and when to remove this template message)|
15 things of megametre scale
|1 Mm in ...||... is equal to ...|
|SI units||×106 m1|
|astronomical units|| 6.6846×10−6 AU
|imperial/US units||621.37 mi|
|nautical units||539.96 nmi|
|Look up megametre in Wiktionary, the free dictionary.|
The megametre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: Mm) or megameter (American spelling) is a unit of length in the metric system, equal to one million metres, the SI base unit of length, hence to km or approximately 621.37 1000 miles.
Megametres (from the Greek words megas = big and metro = count/measure) are rarely seen in practical use, e.g. "" is much more common than "5 Mm". Unless dealing with astronomy, distances on Earth can't be more than 5000 km075 km ( 40Equator length), although megametres may be used to measure the extensions of road systems and air travel distances, among other things rather than distances. The symbol (Mm) can also be confused with millimetres (mm). Megametres are also occasionally found in science fiction.
- The Earth's polar circumference is 39.94 Mm. (It was exactly 40 Mm from 1791 to 1875, but the definition of the metre was changed).
- The distance from Amsterdam to Marseille is 1.01 Mm.
- The distance from New York City to Chicago is 1.14 Mm.
- The Earth's equatorial diameter is 12.76 Mm.
- Quebec province's total area is 1.542 Mm2.
- The mean distance from the Earth to the Moon is 384.4 Mm.
- Jupiter's equatorial diameter is 143 Mm.
- The speed of light is exactly 458 Mm/s by the definition of the metre. 299.792
- SI prefix
- Metric system
- Orders of magnitude (length)
- Conversion of units, for comparison with other units of length
- Light year