Difference between revisions of "Light year"
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| − | A '''light year''' is the distance light travels in one year in a vacuum. | + | A '''light year''' is the distance [[light]] travels in one year in a [[vacuum]].<ref>[https://www.britannica.com/science/light-year Light-year] from britannica.com</ref> It is a measure of [[distance]] used in popular science for distances to great too express in kilometers or miles. |
| − | It is a measure of distance used in popular science for distances to great too express in kilometers or miles. | + | |
Professional [[astronomer]]s prefer to use the [[parsec]] (approximately 3.26 light years) instead of the light year. | Professional [[astronomer]]s prefer to use the [[parsec]] (approximately 3.26 light years) instead of the light year. | ||
| − | The light year is easily derived from the speed of light which is about 300,000,000 meters per second = < | + | The light year is easily derived from the [[speed of light]] which is about 300,000,000 meters per second = 3×10<sup>8</sup> m/s. |
| − | + | Since there are 31,536,000 seconds in one year, a light year can then be calculated to be about 3×10<sup>8</sup> m/s × 31536000 s = 9.46×10<sup>12</sup> km, or 5.9×10<sup>12</sup> miles (5900 billion miles).<br> | |
| − | (To put this in perspective: a person would have to live 31 years, 251 days, 7 hours, 46 minutes, and 39 seconds to reach the age of | + | (To put this in perspective: a person would have to live 31 years, 251 days, 7 hours, 46 minutes, and 39 seconds to reach the age of 1 billion seconds-old.)<ref>http://mathforum.org/library/drmath/view/58739.html</ref> |
| − | The distance in light years is equal to the time a light wave needs to cover that distance<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref> | + | The distance in light years is equal to the time a light wave needs to cover that distance.<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref> Many objects in the universe are more than 10,000 light years away, giving rise to the [[starlight problem]] in [[Creation science]]. A similar problem occurs (the [[Horizon problem]]) in the [[Big bang theory|big bang model]] of the Universe. In the [[Big bang theory]], this problem is resolved by the fact the universe is expanding. |
==References== | ==References== | ||
| − | + | {{reflist}} | |
| − | [[ | + | [[Category:Astronomy]] |
| − | [[ | + | [[Category:Units of Measurement]] |
Latest revision as of 19:12, April 25, 2018
A light year is the distance light travels in one year in a vacuum.[1] It is a measure of distance used in popular science for distances to great too express in kilometers or miles.
Professional astronomers prefer to use the parsec (approximately 3.26 light years) instead of the light year.
The light year is easily derived from the speed of light which is about 300,000,000 meters per second = 3×108 m/s.
Since there are 31,536,000 seconds in one year, a light year can then be calculated to be about 3×108 m/s × 31536000 s = 9.46×1012 km, or 5.9×1012 miles (5900 billion miles).
(To put this in perspective: a person would have to live 31 years, 251 days, 7 hours, 46 minutes, and 39 seconds to reach the age of 1 billion seconds-old.)[2]
The distance in light years is equal to the time a light wave needs to cover that distance.[3] Many objects in the universe are more than 10,000 light years away, giving rise to the starlight problem in Creation science. A similar problem occurs (the Horizon problem) in the big bang model of the Universe. In the Big bang theory, this problem is resolved by the fact the universe is expanding.
References
- ↑ Light-year from britannica.com
- ↑ http://mathforum.org/library/drmath/view/58739.html
- ↑ Wile, Dr. Jay L. Exploring Creation With Physical Science. Apologia Educational Ministries, Inc. 1999, 2000
