Light day: Difference between revisions
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imported>Ro Thorpe m (copyedit) |
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A '''light day''' is the distance that [[light]] travels in a [[vacuum]] in one [[day]] (thus a unit of distance, not time). Similarly, there are the [[light second]], [[light minute]], [[light hour]], [[light week]], [[light month]] and [[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 hour 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 hour is defined exactly. | |||
* [[velocity]] of [[light]] in [[vacuum]]: 299,792,458 m/s <ref>Review of Particle Physics | * [[velocity]] of [[light]] in [[vacuum]]: 299,792,458 m/s <ref>Review of Particle Physics | ||
[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]]) | [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]]) | ||
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===Comparison to other | ===Comparison to other units=== | ||
* 1 light day = 25,902,068,371.200 [[km]] = 2.5902068 * 10<sup>10</sup> [[km]] | * 1 light day = 25,902,068,371.200 [[km]] = 2.5902068 * 10<sup>10</sup> [[km]] | ||
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===Distances in | ===Distances in light days=== | ||
* the maximum distance between [[sun]] and [[Sedna]]<ref>2003 VB12, 90377</ref> is about 133,593 | * the maximum distance between [[sun]] and [[Sedna]]<ref>2003 VB12, 90377</ref> is about 133,593 million km or 5.1 light days | ||
===Notes=== | ===Notes=== | ||
Revision as of 01:08, 7 December 2008
A light day is the distance that light travels in a vacuum in one day (thus a unit of distance, not time). Similarly, there are the light second, light minute, light hour, light week, light month and 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 hour is defined exactly.
- velocity of light in vacuum: 299,792,458 m/s [1] (meters/second)
- 1 day = 24 hour = 1440 minutes = 86400 seconds
- 1 light day = 25,902,068,371,200 m = 2.5902067 * 1013m
Comparison to other units
- 1 light day = 25,902,068,371.200 km = 2.5902068 * 1010 km
- 1 light day = 16,094,799,105.225 mi[2] = 1.6094799 * 1010 mi
- 1 light day = 84,980,539,275,590.551 ft[3] = 8.498053913 ft
- 1 light day = 28,326,846,425,196.850 yd [4] = 2.8326846 * 1013 yd