Reading over Alcubierre's paper on his "warp" drive (http://arxiv.org/abs/gr-qc/0009013), the metric in equation 3 has a velocity term, v, that doesn't seem to be needed anywhere. Even in the one spot where it seems potentially valuable, equation 12, he just call it =1 and essentially ignores it. Also, it doesn't seem to have any mathematical connection to dx/dt (he just randomly says that's what it is after equation 5. So I'm just wondering what it is I'm missing here? Why is the v term included at all? Is there some stronger need that requires it actually be equal to dx/dt? And finally, if v>0, doesn't that then destroy his equation 5 (i.e. 3-space would curve when a body has velocity)? Any insight into that variable would be appreciated.