Light second: Difference between revisions
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The '''light second''' is the distance that the [[light]] travels in [[vacuum]] in one [[second]] and so is a unit of distance. | The '''light second''' is the distance that the [[light]] travels in [[vacuum]] in one [[second]] and so is a unit of distance. | ||
Similar units are the [[light minute]], [[light hour]], [[light day]], [[light week]], [[light month]], [[light year]]. | |||
=== | ===Numerical value=== | ||
As opposed to the [[light year]], whose value more or less depends on the definition of [[year]], the value of the light second is defined exactly. | As opposed to the [[light year]], whose value more or less depends on the definition of [[year]], the value of the light second is defined exactly. | ||
* [[velocity]] of [[light]] in [[vacuum]]: | * [[velocity]] of [[light]] in [[vacuum]]: 299,792,458 m/s <ref>Review of Particle Physics | ||
* 1 light second = 2. | [http://stacks.iop.org/JPhysG/33/1 Particle Data Group: W.-M. Yao ''et al.'', J. Phys. G 33, 1 (2006).]</ref> ([[meter]]s/[[second]]) | ||
* 1 light second = 299,792,458 m = 2.99792458 * 10<sup>8</sup>m | |||
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* 1 [[astronomical unit| AU]] = 499 light seconds | * 1 [[astronomical unit| AU]] = 499 light seconds | ||
* 1 light second = 299,792. | * 1 light second = 299,792.458 [[km]] | ||
* 1 light second = 186,282. | * 1 light second = 186,282.397 [[mi]]<ref>1 mi = 1609.344 m</ref> | ||
* 1 light second = 983,571, | * 1 light second = 983,571,056.4 [[ft]]<ref> 1 ft = 0.3048 m</ref> | ||
* 1 light second = 327,857, | * 1 light second = 327,857,018.8 [[yd]]<ref> 1 yd = 0.9144 m</ref> | ||
===Distances in Light Seconds=== | ===Distances in Light Seconds=== | ||
* the average distance between [[earth]] and [[moon]] is about 1.3 light seconds | * the average distance between [[earth]] and [[moon]] is about 1.3 light seconds | ||
* the average distance between [[earth]] and [[sun]] is about 499 light seconds or 8.3 [[light minutes]] | * the average distance between [[earth]] and [[sun]] is about 499 light seconds or 8.3 [[light minutes]] | ||
===Notes=== | |||
<div class="references-2column"> | |||
<references /> | |||
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===External links=== | |||
* [http://pdg.lbl.gov Particle Data Group & WWW edition of ''Review of Particle Physics''] | |||
* [http://stacks.iop.org/JPhysG/33/1 2006 ''Review of Particle Physics'' in printed layout] | |||
[[Category:CZ Live|Light second]] | [[Category:CZ Live|Light second]] | ||
[[Category:Astronomy Workgroup|Light second]] | [[Category:Astronomy Workgroup|Light second]] | ||
Revision as of 12:59, 7 October 2007
The light second is the distance that the light travels in vacuum in one second and so is a unit of distance.
Similar units are the light minute, light hour, light day, light week, light month, light year.
Numerical value
As opposed to the light year, whose value more or less depends on the definition of year, the value of the light second is defined exactly.
- velocity of light in vacuum: 299,792,458 m/s [1] (meters/second)
- 1 light second = 299,792,458 m = 2.99792458 * 108m
Comparison to other Units
- 1 AU = 499 light seconds
- 1 light second = 299,792.458 km
- 1 light second = 186,282.397 mi[2]
- 1 light second = 983,571,056.4 ft[3]
- 1 light second = 327,857,018.8 yd[4]
Distances in Light Seconds
- the average distance between earth and moon is about 1.3 light seconds
- the average distance between earth and sun is about 499 light seconds or 8.3 light minutes
Notes
- ↑ Review of Particle Physics Particle Data Group: W.-M. Yao et al., J. Phys. G 33, 1 (2006).
- ↑ 1 mi = 1609.344 m
- ↑ 1 ft = 0.3048 m
- ↑ 1 yd = 0.9144 m