Gigametre
| Gigametre | |
|---|---|
 13 objects with sizes in the gigametre order of magnitude | |
| General information | |
| Unit system | metric |
| Unit of | length |
| Symbol | Gm |
| Conversions | |
| 1 Gm in ... | ... is equal to ... |
| SI units | 1×109 m |
| astronomical units | 0.0066846 AU 1.0570×10−7 ly 3.2408×10−8 pc |
| imperial/US units | 621370 mi |
| nautical units | 539960 nmi |
The gigametre (official spelling used by the International Bureau of Weights and Measures;[1] SI symbol: Gm) or gigameter (American spelling) is a unit of length in the metric system, equal to one billion metres, the SI base unit of length. This is equivalent to 1,000,000 km or approximately 621,370 mi.
Gigametres (from the Greek words gigas = giant[2] and metro = count/measure[3]) are composed exactly of 1,000 megametres. Although fit for distances in astronomy (e.g. a planet's distance from its star) this professional field usually uses the astronomical unit (AU) or millions/billions of kilometres.
Examples
- Earth's average distance from the Sun is 149.6 Gm, also referred to as 1 Astronomical Unit.
- Jupiter's average distance from the Sun is 778.5 Gm.
- Osiris' average distance from the parent star HD 209458 is 6.7 Gm.
- PSR J1719-1438 b's average distance from the pulsar PSR J1719-1438 is 0.666 Gm, which is the smallest orbit of any known exoplanets.
- The mean diameter of the Sun is 1.393 Gm.[4]
- The mean diameter of red supergiant star Betelgeuse is 1,302 Gm.
See also
Look up Gigametre in Wiktionary, the free dictionary.
- Conversion of units, for comparison with other units of length
- Light year
- Metric system
- Orders of magnitude (length)
- Parsec
- SI
- SI prefix
References
- ^ "Definition of the metre". BIPM. Retrieved 26 March 2014.
- ^ http://www.merriam-webster.com/dictionary/giga-
- ^ http://www.merriam-webster.com/dictionary/metric
- ^ Emilio, Marcelo; Kuhn, Jeff R.; Bush, Rock I.; Scholl, Isabelle F. (5 March 2012), Measuring the Solar Radius from Space during the 2003 and 2006 Mercury Transits, arXiv:1203.4898