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|May 7, 2007

|May 7, 2007

|The speed of light varies.<ref>http://www.conservapedia.com/index.php?title=Essay:Quantifying_Openmindedness&oldid=147388</ref>

|The speed of light ''in vacuo'' varies, and may have been significantly higher in the distant past.  This phenomenon is known as [[C decay]].<ref>http://www.conservapedia.com/index.php?title=Essay:Quantifying_Openmindedness&oldid=147388</ref> (That the speed of light is significantly different in different media (glass, water, etc.) has been known for hundreds of years, and is the basis for optics.)

|Physicists point out that the [[Theory of Relativity]] and [[Isaac Newton|Newtonian]] physics both demonstrate that the speed of light varies depending on the medium through which it is travelling.

|Physicists point out that the [[Theory of Relativity]] and [[Isaac Newton|Newtonian]] physics both demonstrate that the speed of light varies depending on the medium through which it is travelling.

|"So it turns out the speed of light might not be constant after all." <ref>https://www.newscientist.com/article/dn6092-speed-of-light-may-have-changed-recently</ref><ref>http://www.extremetech.com/extreme/184879-einsteinian-error-the-25-year-old-supernova-that-could-change-the-speed-of-light-forever</ref> Research shows that due to the impossibility of a perfect vacuum the idealized concept of 'the speed of light in a vacuum' cannot be achieved in practice.

|"So it turns out the speed of light might not be constant after all." <ref>https://www.newscientist.com/article/dn6092-speed-of-light-may-have-changed-recently</ref><ref>http://www.extremetech.com/extreme/184879-einsteinian-error-the-25-year-old-supernova-that-could-change-the-speed-of-light-forever</ref> Research shows that due to the impossibility of a perfect vacuum the idealized concept of 'the speed of light in a vacuum' cannot be achieved in practice.