|"So it turns out the speed of light might not be constant after all." <ref>http://www.catholic.org/technology/story.php?id=50261</ref> Research shows that due to the 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>http://www.catholic.org/technology/story.php?id=50261</ref> Research shows that due to the the impossibility of a perfect vacuum the idealized concept of 'the speed of light in a vacuum' cannot be achieved in practice. |