The night sky looks like an upside-down bowl set on the horizon, but as it turns around during the night it is easy to think of it as a giant sphere. Think of the stars as bright points of light lying on the inside surface of a giant celestial sphere. This sphere rotates around us once a day. A model of the sky as a celestial globe explains the appearances of the sky with simplicity and elegance. Learn more about celestial globes with this learning leaflet.