internal warmth. Whenever a kerack dies its pellet is taken to be stockpiled by the colony's queen. The scientists discover the tragic conclusion of the kerack life cycle almost too late to save Merlene; when a kerack colony accumulated a large enough stockpile the queen would instinctively arrange it in such a way as to trigger a nuclear explosion, blasting kerack spores off of the Kuiper belt object to colonize other objects in the belt. Since the kerack colony is exploded in the process no living kerack had known of their fate. The book concludes with Merlene going traveling to warn other colonies of the consequences of their expanding stockpiles. 1999 ZX naming Forward created an impossible name in naming his minor planet. As minor planet provisional designations shows, a name of the form "1999 ZX" is not possible. References 1993 American novels 1993 science fiction novels American science fiction novels Hard science fiction Tor Books books Novels by Robert L. Forward Fiction set in the Kuiper belt Fiction set in the Oort cloud Fiction set in 2009