I just swung there in my hammock and played the game called Toby Halpert’s Place in the Universe. No egotist, I put the sun in the center, the luminary, the orb of day. Around it I swung tidy planets, our cozy home system. But just here, at a fixed point about an eighth of the way out toward the orbit of Mars, I hung a fat alloy cylinder, like a quarter-scale model of Tsiolkovsky 1, the Worker’s Paradise back at L-5. Tsiolkovsky 1 is fixed at the liberation point between Earth’s gravity and the moon’s, but we need a lightsail to hold us here, twenty tons of aluminum spun into a hexagon, ten kilometers from side to side. That sail towed us out from Earth orbit, and now it’s our anchor. We use it to tack against the photon stream, hanging here beside the thing the point, the singularity we call the Highway.