"This done, they waited until the moment calculated by their astronomers, then aimed the great projector-tube at the edge of their sun that was rotating away from them, and turned on the ray. This was the crucial point of their scheme, for now they were risking their very universe. It was necessary for them to increase their sun's rate of spin just enough to make it swerve aside, but if the rate of spin were increased just a little too much it would mean disaster, since when a sun spins too fast it breaks up like a great flywheel, splits into a double star. It is that process, the process of fission, which has formed the countless double stars and bursted suns in the heavens around us, since each was only a single star or sun which broke up because of its too-great speed of rotation, or spin. And the globe-men knew that it would require but very little increase in their own sun's rate of spin to make it, too, split asunder. So they watched with infinite care while their brilliant ray stabbed up toward the sun's edge, and when, under the terrific power of that pushing ray, the star began to spin faster, they at once turned off the ray, which was used for a short time only. But it had been effective; for now, as their sun spun faster, it began to swerve a little from its usual course, and they knew that now it would crash into the other approaching sun instead of passing it. So their end was achieved, and so they began their preparations for their great migration out to Alto's outermost planets, a migration which would take place just before the collision. And then--we came. "We came, and now we have discovered that for which we came, the reason for Alto's change in course. For it was the science and will of the globe-men that turned their sun aside, that threatens now the annihilation of the Eight Worlds. Doom presses upon them, and to escape that doom they are destroying our sun, our planets, our very universe!" 4 I do not remember that any of us spoke when Sarto Sen's voice had ceased. And yet, stunned as we were by the thing he had told us, our knowledge was in some ways a relief. We had discovered, at least, what had swerved Alto from its course, and if science and intelligence alone could cause the sun to veer from its path, science and intelligence might steer it back into that path. When I said as much to Sarto Sen his face lit up. "You are right, Jan Tor!" he exclaimed. "There's a chance! And even as Mur Dak predicted, that chance depends on us. For if we can escape from here and get back to the Eight Worlds, we can come back with a greater force and crush these globe-men, and use their own force-projector to swerve their sun out of its present path." "But why go back to the Eight Worlds?" objected Hal Kur. "Why not get up to that platform, if we escape, and use the projector ourselves?"