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Why can't you trap light in a box? Presumably the photons are still around when you close the lid, but it goes dark. I am really enjoying your site, even if most of it is over my head. Thanks.
You are right. The photons are still there. If the insides of the box were perfectly reflecting, like mirrors, the photons would just bounce around for a long time. However, all surfaces have a certain amount of absorption that will eventually eat up the photons. There is always a certain amount of thermal radiation in the box, but that is another story.
(published on 12/23/09)
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