Hejhej, There is a religious forum where I am posting in some evolution vs. creation threads. Creationists often believe that the world and everything else has not existed much longer then several thousands years. If you ask them how to explain that the light from stars millions of light years away can be seen here, they give various explenations you can usually easily show to be ridiculous. But now someone mentioned that the speed of light might not have been constant during the years because of virtual particles. Photons interact with virtual particles he says, slowing them down a bit. Well, the speed stays the same, but the photons lose some time while interacting with the virtual particle. Also according to him, there are more virtual particles now, then there were at earlier times, because of an increase in the Zero Point Energy. I haven't done more physics than the most you could do at highschool, and that only mentioned quantum physics as existing and difficult to understand, so I do not know if this person is making sense in his statements. Perhaps some persons here could shine their light on it? Do photons really interact with virtual particles? Does this interaction take time? Is the ZPE increasing? Opinions are very much appreciated.