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As weak brilliance of the sun and your eyes accustomed to the night sky filled with stars gradually. Thousands of people ultralight plane is blue, silver and white, some gold, some are red… It seems there in the darkness, one bowl, in the spheres of the earth's total unit is your position.           The Celestial Sphere       We’ve become jaded—a bit spoiled—by the increasingly elaborate and costly special effects in today’s sci-fi flicks, but none of us these days is nearly as spoiled as the sky most of us look at. Imagine yourself as one of your ancestors, say ten thousand years ago. Your reality consists of a few tools, household utensils, perhaps buildings (the city-states were beginning to appear along the Tigris) and, of course, all that nature has to offer: trees, hills, plants, rivers, streams—and the sky.   The sky is the biggest, greatest, most spectacular object you know. During the day, the sky is crossed by a brightly glowing disk from which all light and warmth emanate. Announced in the predawn hours by a pink glow on the eastern horizon, the great disk rises, then arcs across the sky, deepening toward twilight into a ruddy hue before slipping below the horizon to the west. Without electric power, your working hours are dictated by the presence of the sun’s light.   As the sun’s glow fades and your eyes become accustomed to the night, the sky gradually fills with stars. Thousands of them shimmer blue, silvery white, some gold, some reddish, seemingly set into a great dark bowl, the celestial sphere, overarching the flat earth on which you stand.   ... Ten thousand years ago, family time at night was not occupied with primetime sitcoms followed by the news and David Letterman. Our ancestors were not glued to television screens, but presumably to the free show above, the celestial sphere. Early cultures noticed that the bowl above them rotated from east to west. They concluded that what they were seeing was the celestial sphere—which contained the stars—rotating, and not the individual stars. All the stars, they noticed, moved together, their positions relative to one another remaining unchanged. (That the stars “move” because of Earth’s rotation was a concept that lay far in the future.)   The coordinated movement of the stars was in dramatic contrast to something else the ancient sky watchers noticed. While the vast majority of stars were clearly fixed in the rotating celestial sphere, a few—the ancients counted five—seemed to meander independently, yet regularly, across the celestial sphere. The Greeks called these five objects planetes, “wanderers,” and, like nonconformists in an otherwise orderly society, the wanderers would eventually cause trouble. Their existence would bring the entire heavenly status quo into question and, ultimately, the whole celestial sphere would come crashing down.              — Christopher De Pree, Alan Axelrod, The Complete Idiot's Guide to Astronomy             Indexes/03