In the first episode of the TV series Terra Nova, Maddy and her little sister see The Probe. It's the first item that they send back into the past, but they never found it in the future.
I believe she says that because The Probe was never found in the future, they are in some other sort of time-stream - meaning that there would be no risk to the future if history was altered.
So what happens in Terra Nova doesn't have an impact on the future? Yet in one of the last episodes Lucas Taylor states:
Control the past, control the future.
What does he mean by that if whatever happens in Terra Nova doesn't have an impact on the future?