Astronomers have been bewildered by the theory of an expanding universe, but there is no less expansion in the moral infinite of the universe of man. As far as the frontiers of science are pushed back, over the extended arc of these frontiers one will hear the poet's hounds on the chase.
The acknowledged legislators of the world take the world as given. They dislike mysteries, for mysteries cannot be coded, or legislated, and wonder cannot be made into law. And so these legislators police the accepted frontiers of things.
I'm very optimistic because I think that the real strength of a nation like the United States comes from blending cultures. There's no way that you can close the frontiers anywhere. The borders are there to be violated permanently.