I am curious and if some of you know, please elucidate and clarify. The upcoming series, "Terra Nova" is about us humans traveling back in time to start over. Apparently, they/we do not travel to other dimensions, just earth in the past. So if they go back, how come scientists in their future (us) did not find evidence of it? Seems logical that if a bunch of people went back in time and lived, we would know about it today because we would find evidence of an advanced civilization (us) among the bones and other things we are finding today. Think paradox. Anyone know if this was or will be handled by something I am missing or did the producers simply say, "Aw, screw it. Ignore the paradox and forward thinking people, they wont catch the (possible) mistakes that occur whenever one writes about travels in time and tries to deal with paradoxical problems and logic."