Descending Road - CITY INTRODUCTION by Dana W. Paxson

CITY INTRODUCTION

1563 4D

The city of Gran Dar, usually called simply the City, is the largest subterranean urban structure on Tarnus, much larger than Monford or Purusil or any other inhabited space. It is estimated to reach nine kilometers below the surface of the planet, and spreads out about ninety kilometers in diameter, counting all the outliers and connecting communities and facilities bound closely to its workings. The actual convex contour of the City proper is that of an oblate spheroid 70 kilometers across and 9 kilometers deep, with one pole at the planet‘s surface, the other directly below it at the unreachable bottom of the City. The lowest explored level is 7800 meters down from the surface.

The sheer density and complexity of the City of Gran Dar appalls the imagination. The City Profile shows a horizontal line for every ten levels of streets within the City, because portraying all level in this cross section would yield a nearly-solid gray area. The great airshafts of the City are not shown except for one: Shaft Arbonel, the thin vertical line visible to the right of center reaching all the way to the surface. There are thousands of these shafts, augmented by the screwstairs of modern times, that provide added ventilation for City dwellers. In this image there are about ninety lines reflecting the 900 levels of the City that are believed to exist. Below Level 780, no successful explorations have been made; the actual existence of City levels below that is conjectural, based on the symmetries with which the City‘s builders endowed it. It is estimated that the City, when fully inhabited, could comfortably support 2200 million people.

The City is carved, drilled, and shaped out of a single unusual kind of native rock that seems far too homogeneous, tough, and free of faultlines to be natural in its origin. Analysis of this stone reveals a three-phase material with crystalline, glassy, and metallic structures intermixed so as to produce a workable material of exquisite toughness, hardness, and malleability – qualities which would generally not be shared in a single material, let alone in any form of mineral. The City can be dated by radiological means to an age of at least fifteen thousand years, with almost no deterioration or collapse due to geological processes. This unexpected state of affairs attests to its long-term structural integrity.

The City is essentially a stack of disks of radial and concentric-ring streets around a single central axis. Adjacent layers of the stack are 10 meters apart vertically, yielding a total of 900 levels. Airshafts and stairs give interlayer access. Added interlayer connection is provided by the turnings, a set of broad, sloping streets that spiral out and down from the central axis to define ellipsoidal, concentric, convex contours of the same shape as the City itself.

Story List	SURPRISE ME	Author Page
USER SURVEY	PUZZLE ME	MAKE ELM MARK

HOVER Lucida Bright BARE	HOVER Lucida Bright FULL	HOVER Palatino Linotype BARE
HOVER Palatino Linotype FULL	HOVER Times New Roman BARE	HOVER Times New Roman FULL
PAD Arial BARE	PAD Arial FULL	PAD Lucida Bright BARE
PAD Lucida Bright FULL	PAD Times New Roman BARE	PAD Times New Roman FULL


	CITY INTRODUCTION 1563 4D The city of Gran Dar, usually called simply the City, is the largest subterranean urban structure on Tarnus, much larger than Monford or Purusil or any other inhabited space. It is estimated to reach nine kilometers below the surface of the planet, and spreads out about ninety kilometers in diameter, counting all the outliers and connecting communities and facilities bound closely to its workings. The actual convex contour of the City proper is that of an oblate spheroid 70 kilometers across and 9 kilometers deep, with one pole at the planet‘s surface, the other directly below it at the unreachable bottom of the City. The lowest explored level is 7800 meters down from the surface. The sheer density and complexity of the City of Gran Dar appalls the imagination. The City Profile shows a horizontal line for every ten levels of streets within the City, because portraying all level in this cross section would yield a nearly-solid gray area. The great airshafts of the City are not shown except for one: Shaft Arbonel, the thin vertical line visible to the right of center reaching all the way to the surface. There are thousands of these shafts, augmented by the screwstairs of modern times, that provide added ventilation for City dwellers. In this image there are about ninety lines reflecting the 900 levels of the City that are believed to exist. Below Level 780, no successful explorations have been made; the actual existence of City levels below that is conjectural, based on the symmetries with which the City‘s builders endowed it. It is estimated that the City, when fully inhabited, could comfortably support 2200 million people. The City is carved, drilled, and shaped out of a single unusual kind of native rock that seems far too homogeneous, tough, and free of faultlines to be natural in its origin. Analysis of this stone reveals a three-phase material with crystalline, glassy, and metallic structures intermixed so as to produce a workable material of exquisite toughness, hardness, and malleability – qualities which would generally not be shared in a single material, let alone in any form of mineral. The City can be dated by radiological means to an age of at least fifteen thousand years, with almost no deterioration or collapse due to geological processes. This unexpected state of affairs attests to its long-term structural integrity. The City is essentially a stack of disks of radial and concentric-ring streets around a single central axis. Adjacent layers of the stack are 10 meters apart vertically, yielding a total of 900 levels. Airshafts and stairs give interlayer access. Added interlayer connection is provided by the turnings, a set of broad, sloping streets that spiral out and down from the central axis to define ellipsoidal, concentric, convex contours of the same shape as the City itself.