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|May 7, 2007

|May 7, 2007

|A [http://www.conservapedia.com/index.php?title=Essay:Quantifying_Openmindedness&oldid=147388 quiz] suggests that willingness to consider that the speed of light has been different in the past could be used as a measure of openmindedness. While the quiz takes no position on this question, there are articles in scientific magazines exploring this issue and suggesting that it may very well have been different as recently as 2 billion years ago.<ref>https://www.newscientist.com/article/dn6092-speed-of-light-may-have-changed-recently</ref>

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

|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.

|An article "Einsteinian error: The 25-year-old supernova that could change the speed of light forever."<ref>http://www.extremetech.com/extreme/184879-einsteinian-error-the-25-year-old-supernova-that-could-change-the-speed-of-light-forever</ref> appears on the internet.  It is not about an actual change to the speed of light, but to a change in the way the "speed of light" is perceived.  It turns out that light doesn't actually travel at that speed; it's slower by about 1 part in 300 million due to vacuum polarization. See,<ref>http://www.conservapedia.com/Speed_of_light#Does_light_travel_at_the_.22speed_of_light.22.3F</ref><ref>http://www.conservapedia.com/Speed_of_light#Has_the_speed_of_light_changed_through_the_history_of_the_universe.3F</ref> and <ref>http://www.conservapedia.com/C_decay</ref>

|"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.

|March 25, 2013

|March 25, 2013

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