"Yes. The three-day variables are used for course markers; the longer variables are used to denote gas fields, nebular dust, and the like, and the still-longer beacons are used to denote places where various well-travelled starlanes meet, cross or merge. It is—"
"Three day variable—" breathed Dusty.
"Yes. In three days Sol will rise ten times its present brightness and fall again to less than one tenth of the present brightness. This is accomplished by creating an atomic instab—"
"My God! How can any race live under such conditions?"
"They cannot. Not unless properly prepared, well taken care of, aware and ready for it."
"Look," snapped Dusty. "Why not go out and use some other star for your damned beacon?"
Scyth shook his head. "If we were gods," he said quietly, "we could park the Galaxy on our desk, pick up a broom-straw and by fitting and trying we could locate the best course through the star-fields. But—"
"If you were gods," grunted Dusty bitterly, "you could reach in and move a few stars aside and run your damned channel on a dead line from one end to the other. So why do you use Sol?"
"Because the two straightaway lanes that meet at Sol do not meet at some other star. In one or two cases along this rift the original surveyors provided alternates in case we ran into trouble. But not on this one. No, Dusty, we cannot change our plans."
"But see here—"