"Briefly, Fuller has produced a model of the equilibrium states of various atmospheric gases and volcanically introduced water vapor, that is consistent with known data. To sustain the levels of free atmospheric carbon dioxide and water vapor, and the existence of large amounts of water in a liquid state, the model requires a very high level of volcanic activity on the planet, at least in its earlier history. That this requirement was evidently met could suggest that relative to its size, the crust of Minerva was exceptionally thin, and the structure of this crust unstable. This is significant, as becomes clear later. Fuller's model also ties in with the latest information from the Asteroid surveys. The thin crust could be the result of relatively rapid surface cooling caused by the vast distance from the Sun, but with the internal molten condition being prolonged by heat sources below the surface. The Asteroid missions report many samples being tested that are rich in radioactive heat-producing substances.

"So, Minerva cooled to a mean surface temperature somewhat colder than Earth's but not as cold as you might think. With cooling came the formation of increasingly more complex molecules, and eventually life emerged. With life came diversification, followed by competition, followed by selection—in other words, evolution. After many millions of years, evolution culminated in a race of intelligent beings who became dominant on the planet. These were the beings we have christened the Ganymeans.

"The Ganymeans developed an advanced technological civilization. Then, approximately twenty-five million years ago, they had reached a stage which we estimate to be about a hundred years ahead of our own. This estimate is based on the design of the Ganymean ship we've been looking at here, and the equipment found inside it.

"Some time around this period, a major crisis developed on Minerva. Something upset the delicate mechanism controlling the balance between the amount of carbon dioxide locked up in the rocks and that in the free state; the amount in the atmosphere began to rise. The reasons for this are speculative. One possibility is that something triggered the tendency toward high volcanic activity inherent in Minerva's structure—maybe natural causes, maybe something the Ganymeans did. Another possibility is that the Ganymeans were attempting an ambitious program of climate control and the whole thing went wrong in a big way. At present we really don't have a good answer to this part. However, our investigations of the Ganymeans have hardly begun yet. There are still years of work to be done on the contents of the ship alone, and I'm pretty certain that there's a lot more waiting to be discovered down under the ice here.