The city has become a separate world with its own climate, no real night/day cycle, and an artificial sky that is always grey.

They were alone, and falling snow turned the artificial sky into an opalescent bowl.

To his right, twisted brass spires reached to an artificial sky.

Above it all, the twin ribbon-suns curved away out of sight in their artificial sky.

He did not want to pass below that vaulted ceiling for fear that the artificial sky would fall.

Slowly the lid came down, like an artificial sky, shutting out the mundane world.

The atomic sun circling the artificial sky burned less harshly here than in the forward section of the city.

He shot a hand toward the artificial sky, finger pointed.

She looked up and saw a bright blue artificial sky.

Under a hemisphere of artificial sky, a sun burned low, red, and flattened.