On Fri, Sep 23, 2011 at 2:00 PM, Jim Higgins wrote: > >>Refraction index depends on lots of parameters not just the wavelength of >>the source. It is a macroscopic manifestation of the molecular structure. >>It's a scale to compare materials ratios of interactions with vacuum wher= e >>there is no interaction and light is at it's maximum speed. Since they >>artificially generate neutrinos they have the very specs of them. Also si= nce >>they constructed the tunnel specifically for this purpose, it is easy to >>calculate and measure the refractive index through the propagation medium >>(the tunnel), fairly easy process. > > > Not quite so easy because there isn't a 732 km tunnel. =A0Other than a bi= t of > tunnel housing the equipment on each end, the path is thru the earth. =A0= I'm > sure the characteristics of that path can be estimated fairly closely, bu= t > how do they know for sure? =A0What are the margins of error on that > estimate? =A0Would we still have faster than light neutrinos if we assume= one > or the other bookend values for the speed of light along that path. > > Light is fastest in a vacuum. =A0It's slower in all other media. =A0If th= e speed > of light calculated for the rocky path is too low, then neutrinos travell= ing > at the true speed of light in that medium will appear to be travelling fa= ster > than light should travel in that medium. Something exceeding the speed of light in the local medium is a well known phenomena -- see Cherenkov radiation (i.e. http://en.wikipedia.org/wiki/Cherenkov_radiation). This is faster than the speed of light in a vacuum. Bill --=20 Psst...=A0 Hey, you... Buddy...=A0 Want a kitten?=A0 straycatblues.petfinde= r.org --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .