A recent article on the io9 website (The Scharnhorst Effect claims we've got the speed of light wrong) speculated that light passing between two plates demonstrating the Casimir Effect might travel slightly more quickly than light through an ordinary vacuum, due to there being less vacuum energy there. I was wondering if the transmission of light through a vacuum is dependent in any way upon the vacuum energy, or if light could travel through a truly “empty” vacuum.
We already have a thread going about this, I believe:
http://boards.straightdope.com/sdmb/showthread.php?t=686255&highlight=light+vacuum
Mods, please merge threads.