On 1/22/07, Michael Rigby-Jones wrote: > > I've almost certainly misunderstood this quote, but how can a mask possibly cause a single photon to cast a shadow? A shadow is just the contrast between high and low light areas, so with a single photon how can the shape of this area be defined? Sounds like the single photon expermient: http://www.physique.ens-cachan.fr/franges_photon/index.htm It's not a particle, it's a wave-particle duality. Alex -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist