We find a set of data that strongly implies the presence of complex organic molecules in the outer solar system. - Carl Sagan

the pattern-recognition machinery in our brains is so efficient in extracting a face from a clutter of other detail that we sometimes see faces where there are none. We assemble disconnected patches of light and dark and unconsciously try to see a face. The Man in the Moon is one result. Michelangelo Antonioni’s film Blowup describes another. There are many other examples.

In those cultures lacking unfamiliar challenges, external or internal, where fundamental change is unneeded, novel ideas need not be encouraged. Indeed, heresies can be declared dangerous; thinking can be rigidified; and sanctions against impermissible ideas can be enforced — all without much harm. But under varied and changing environmental or biological or political circumstances, simply copying the old ways no longer works. Then, a premium awaits those who, instead of blandly following tradition, or trying to foist their preferences on to the physical or social Universe, are open to what the Universe teaches.

That's what this book is about: other worlds, what awaits us on them, what they tell us about ourselves, and - given the urgent problems our species now faces - whether it makes sense to go.

Should we solve those problems first?

Or are they a reason to go?