If interstellar travel is as time- or energy- demanding as the above figures indicate, it is far from obvious what the motive for colonization might be.

I'm a Christopher Nolan fiend. I love 'Inception,' 'Interstellar,' 'The Prestige,' 'Memento' and of course the Batman trilogy. I love all his movies.

We don't know how to identify intelligence over interstellar distances, so what we do instead is use technology for a proxy.

Like a blazing comet, I've traversed infinite nights, interstellar spaces of the imagination, voluptuousness and fear.

What have we been doing all these centuries but trying to call God back to the mountain, or, failing that, raise a peep out of anything that isn't us? What is the difference between a cathedral and a physics lab? Are not they both saying: Hello? We spy on whales and on interstellar radio objects; we starve ourselves and pray till we're blue.

If interstellar travel is as time- or energy- demanding as the above figures indicate it is far from obvious what the motive for colonization might be.