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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 = <B><math>3\times10^8</math></B>m/s.

The light year is easily derived from the speed of light which is about 300,000,000 meters per second = '''<math>3\times10^8</math>'''m/s.

A light year can then be calculated to be about <math>3.00 \times 10^8 m/s \times 3600s \times 24 \times 365</math> = <B><math>9.46\times10^{12}km</math></B> , or <B><math>5.9\times10^{12}</math></B> miles (5900 billion miles).<br>

A light year can then be calculated to be about <math>3.00 \times 10^8 m/s \times 3600s \times 24 \times 365</math> = '''<math>9.46\times10^{12}km</math>''' , or '''<math>5.9\times10^{12}</math>''' 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 '''1 billion''' seconds-old.)<ref>http://mathforum.org/library/drmath/view/58739.html</ref>

(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> . Many objects in the universe are more than 10,000 light years away, giving rise to the [[starlight problem]] as well as the Horizon Problem in the Big Bang Model of the Universe.

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]] as well as the Horizon Problem in the Big Bang Model of the Universe.

==References==

==References==

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[[category:astronomy]]

[[Category:Astronomy]]

[[category:units of Measurement]]

[[Category:Units of Measurement]]