Tom Thumb
Yes, superstring theory (one of the proposals for the Universal Theory) does say that.
However I believe they are off track in stating there are "curled" or "shrunken" dimensions.
I believe there are actual Dimensions that have yet to be defined or proven.
This is one of the things I am working on.
It's going to "fun" to prove.
RatherThanWords
Take a look again.
Actually, I DID state that light would slow down slightly in a different medium. (such as glass or water, etc)
Which is why when I referred to the speed, I said, "in a vacuum".
It is not constant, but it is a "Constant".
Different definition.
Whenever you want to take an exact measure,
you should try to do it in a vacuum
Otherwise your measurement is altered by the enviroment.