For all its material advantages, the sedentary life has left us edgy, unfulfilled. Even after 400 generations in villages and cities, we haven't forgotten. The open road still softly calls, like a nearly forgotten song of childhood.

We invest far-off places with a certain romance. The appeal, I suspect, has been meticulously crafted by natural selection as an essential element in our survival. Long summers, mild winters, rich harvests, plentiful game - none of them lasts forever. Your own life, or your band's, or even your species' might be owed to a restless few - drawn, by a craving they can hardly articulate or understand, to undiscovered lands and new worlds.

Herman Melville, in Moby ♥♥♥♥, spoke for wanderers in all epochs and meridians. He said: "I am tormented with an everlasting itch for things remote. I love to sail forbidden seas..."

Maybe it's a little early. Maybe the time is not quite yet. But those are the worlds - promising untold opportunities - beckon. Silently, they orbit the Sun, waiting.

- Carl Sagan