Gant Nerley picked up a small cylinder from a rack on the railing of the catwalk. A narrow pencil of light pointed out, and he aimed it towards the center, some five hundred feet out to the middle of the hall. "Marandis," he said. Then he brought the pointer-light across towards them slowly, to stop a hundred feet from their position. "Sol," he said. "The lines are courses surveyed and registered by the various companies, you can gather that the colored stars are our inhabited systems and the volumes register certain clusters. That faint greenish-yellow course that ends out there by Sol is the Transgalactic course set up to reach from Marandis to the Spiral Cluster which lies almost at our feet." The magnificence of the spectacle was enhanced by the silence in the room. The galaxy, it seemed, lay at their feet and with no irreverence, and only awe, the viewer felt as though he were standing by the side of God, looking down at his Work. In a hushed voice, Dusty asked, "Is this where they survey the courses? Couldn't figure out a way around Sol?" Gant laughed sympathetically, breaking the hushed awe. "Look at it and think, Dusty Britton." Dusty looked, and Barbara looked, both in awed silence as Gant Nerley went on: "In that model, which looks like a wisp of gas, there are fifteen billion individual pinpoints. Think, Dusty. One-five, comma, zero-zero-zero, comma, zero-zero-zero, comma, zero-zero-zero stars in one galaxy. Across the breadth of this room it lies, scaled down to represent the hundred thousand light-years of its diameter at the rate of a hundred light-years to the foot. Eight and one third light years per inch, Dusty Britton, so your Sol and your Sirius lie about an inch apart. Now, Dusty, in order to make the stars visible, they must be above a certain intrinsic size, and in the size of the stars the scale of the model is violated. Each tiny glowing point is about one-sixteenth of an inch in diameter. That makes the scalar size of the stars about a half light year in diameter. The diameter of the colored lines that represent courses is of the same magnitude, so as we go into the model--as we may--we will find that the courses touch, intersect, and lie tangent to stars that are actually far from the flight in real space. "What I am saying, of course, is only a new concept of something that you already know, but pertaining to another subject with which you have every right to be more familiar. Take a globe of your Terra. It is excellent for locating areas, finding cities, lakes, oceans, mountain ranges; anything gross enough to find physical size upon the map. But you cannot use it for a road map to direct you to the home of a friend, because the details of such a trip are much too fine. So we use it for large-scale mapping, but could not possibly use it for the delicate business of course mapping." "But if you enlarged a section?"