Changes

Since the speed of light in a vacuum is presently constant, it can be used to define distances as well.  The distance that light travels in one year is know as a [[light-year]], which is about 6 million million (6x10^12) miles.  For instance, the nearest large galaxy to our own [[Milky Way Galaxy]] is the [[Andromeda Galaxy]], which astronomers have measured to be about 2.5 million light years away.

Since the speed of light in a vacuum is presently constant, it can be used to define distances as well.  The distance that light travels in one year is know as a [[light-year]], which is about 6 million million (6x10^12) miles.  For instance, the nearest large galaxy to our own [[Milky Way Galaxy]] is the [[Andromeda Galaxy]], which astronomers have measured to be about 2.5 million light years away.

Young earth creationist scientists propose that the speed of light has not been constant throughout the duration of the universe.  <ref>[http://www.answersingenesis.org/creation/v4/i1/light.asp]</ref><ref>http://www.answersingenesis.org/news/fine_structure.asp</ref><ref>http://www.answersingenesis.org/tj/v17/i2/cosmology.asp</ref>

[[Young Earth Creationism|Young earth creationist scientists]] propose that the speed of light has not been constant throughout the duration of the universe.  <ref>[http://www.answersingenesis.org/creation/v4/i1/light.asp]</ref><ref>http://www.answersingenesis.org/news/fine_structure.asp</ref><ref>http://www.answersingenesis.org/tj/v17/i2/cosmology.asp</ref>

==References==

==References==

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