 What happened to Earth?
The ancient rule was sink or swim—swim in the miasma of a planet without spaceflight, or sink to utter destruction! [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, July 1963. The last contact the Ship had had with it—and we were the ones who dropped them—was almost 150 years ago. One of the eight, as well as the two that were being built then, went up with everything else in the Solar System in 2041. I don't know how many of those planets had animals that could have been substituted but, even if they had, they would have had to be domesticated from scratch.
 Overpopulation caused a war
 People divided into small, vicious colonies  Overpopulation caused a war  People discovered more planets and chose to move  Everyone chose to live in space