Upsampleing?

I have a little problem understanding the concept of upsampling. Maybe someone can explain it to me. If a redbook CD is 44.1hz how can upsampling produce a 192hz out of a 44hz disc? Doesn't the disc only have 44hz on it, so therefor is the upsampling just bridging the "gaps" and essentially smoothing out the sampling rate segments?
I wonder if the improved sound is really a fabrication more than an unrevealing of music that is supposedly there in the disc and being missed by most players.