I came to a stop, relatively speaking, more than fifty AU out from Eta Leporis. The definitions of Kuiper and Oort regions were completely arbitrary, especially for a system other than Sol, but there were some practical differences. For instance, matter became increasingly scarce farther out. And metallic deposits became harder to find. The physics of stellar system formation seemed to produce some consistent patterns, one of which was that the heavier elements tended to be closer in, and all the ice and frozen gasses congregated farther out. In the Kuiper and Oort zones, it was almost all frozen clumps of condensed gasses ejected from the inner system when the sun ignited. But, like raindrops, they generally condensed around something .