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by Pete Grey

One of the main principles of planetary geology is the principle of isostasy. Isostasy is a fancy word for buoyancy, specifically properties of one material floating within a medium of different consistency or density.

The lithosphere, which is to say the rocky and solid part of a planet, is almost never a homogenous structure. Because of differences in temperature, pressure, mass and the continuing influence of bolide (meteorite) collisions with a world, the lithosphere is divided into several layers. For a "molten" core world, the topmost layer is the crust, which consists of either light continental crust and/or denser oceanic crust. Beneath these rocks are the upper mantle. Collectively these three regions are termed the Asthenosphere.

On Earth the continents have a density of 2.8 g/cm3, the oceanic rock is 3.1 g/cm3, and the upper mantle is 3.3 g/cm3. Because of the minor differences between their densities, the degree of displacement that must exist within the mantle due to the overriding crustal rock is quite significant. There exists more continental crustal rock under the base level (the extant surface of the mantle) than exists above the surface, whether it be flat plains or mountains. Oceanic rock is mostly flat slabs a few kms thick, but continental crust can be up to 50 kms in thickness in mountain ranges, nearly all of it subterranean.

But normal isostasy assumes 1G acceleration on the floating material. That means that buoyancy changes proportionally with the amount of gravitational acceleration. That means that objects have greater buoyancy on smaller worlds, but less on more massive worlds. This explains the strange paradox first observed by the Solomani in regards to their home system: smaller worlds and moons in the Terra system have more massive geological features. The greater buoyancy allows more massive features to exist without having to displace more medium (that is to say its sinks) in compensation.

Denanus is a world a scant 3200 miles in diameter, and possessing a gravitational force a mere one-third normal. But it has mountains that are twice as high as Terra's Himilaya and Andean ranges. In fact about two thirds of the world has an elevation of greater than 2000 meters. Much of this is high intermontane plateaus and rift valleys, most of its unsuitable for agriculture or major habitation. Most of the population is divided along the worlds coastlines where elevations allow for flat ground, and where air pressure allows for normal respiration. The world is violently active, and active volcanos and earthquakes are common. Tectonic velocities are about twice Terran values, which on a small world creates massive changes within small time frames!

The world is still young, and O2 pressure is rather low as the local photosynthesizers have not produced enough for unassisted respiration. Most of the population is committed to primary industries like mining and basic aquaculture. The mounatins are still bare, and mulicellular plant life has not yet gained much of a foothold on the coastlines either. Some agriculture has been accomplished where soils have begun to form, particularly within river deltas. Most local mining consists of large placer operations, as erosion from the local mountains chokes the rivers with mineral rich sediment that is extracted and sifted out.

The world government consists of the individual settlement administrations operating in an overlapping fashion. Many of these are private companies that have divided the arable land into private fiefdoms, and have just enough goodwill between them to create a single set of ruling protocols for the populace. The consortium of companies has become more and more Regency dominated, either directly by Reg corps or by immigrant enterprises. The Avalar naval base is primarily a training facility for wilderness operations, and is of little importance politically.

Denanus and its mountains have attracted a steady stream of daredevils and expert climbers in the last forty years or so. The extreme heights and the severe lack of oxygen in the thin atmosphere make these mountains among the most dangerous in Charted Space, and climbing can only be accomplished with air tanks or environmental suits of some sort. Coupled with the very cold temperatures at higher elevations, and the world has a steady stream of casualties during the main climbing seasons.

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