Re: Ancient Aliens
OTOH, the moon, Mars and the asteroids could be settled for relatively little expense, in a fraction of the time and for a fraction of the expense as an interstellar voyage. If you're going to use Von Neuman machines for anything, THAT is the way to go.
Hence the Hawking quote I posted...
It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring. Carl Sagan