User:Fosnez/Globus Cassus

Globus Cassus is a utopian project for the transformation of Planet Earth into a much bigger, hollow, artificial world with an ecosphere on its inner surface. Sunlight would enter through two large windows, and gravity would be provided by centrifugal force. Humans would live on two vast regions that face each other and that are connected through the empty center.

Being the Earth/World's antipode in many aspects, Globus Cassus acts as a philosophical model for the opposite-based description of the Earth/World and as a tool to understand the World's real functioning processes.

Globus Cassus was proposed by architect and artist Christian Waldvogel and presented at the Venice Architecture Biennale in 2004. It consists of a meticulous description of the transformation process, a narrative of its construction as well as of suggestions on the organizational workings on Globus Cassus. It is also the subject of a book.

Properties
The proposed megastructure would incorporate all of Earth's matter. The hydrosphere and atmosphere would be retained on its inside. The ecosphere would be restricted to the equatorial zones, while at the low-gravity tropic zones a thin atmosphere would allow only for plantations. The polar regions would have neither gravity nor atmosphere and would therefore be used for storage of raw materials and microgravity production processes.

Geometric structure
Globus Cassus has the form of a compressed geodesic icosahedron with two diagonal openings. Along the edges of the icosahedron run the skeleton beams, the gaps between the beams contain a shell and, where there are windows, inward-curving domes.

Building material
Earth's crust, mantle and core are gradually excavated, transported outwards and then transformed to larger strength and reduced density. While the crust is mined from open pits in the continent's centers, magma and the liquid mantle are pumped across transfer hoses. The core is dismantled from the surface.

Planetary scale
Since the stationary cables would stay clear inside the moon's trajectory, the construction of Globus Cassus would not alter the Earth-Moon system. However, on planetary scale the proportions would be altered, with Globus Cassus being only slightly smaller than Saturn, the Solar System's second-largest planet.

Construction process
Starting at four precisely defined points in the geostationary orbit, four space elevators are built. Consequently they become massive towers, each measuring several hundred kilometers in diameter and extending to a length of about 165,000 km. The towers contain elevators which are used to transport silicate building material to the construction sites at geostationary orbit.

Skeleton and shell
The building material is converted into vacuum-porous aggregate and used to form the skeleton. It is built retaining constant symmetry and balance at every moment and will ultimately span around all sides of the earth. Then magma is pumped towards the skeleton, where it is used to form thin shells in the skeletal openings. Eight of these openings are fitted with large, inward-curving window domes made out of silicon glass.

The Great Rains
Having been used up to a large degree, the Earth has shrunk, the polar ice caps have melted and the Earth's mass and therefore gravity has declined. This leads to the sudden loss of the atmosphere and hydrosphere, which wander outwards towards the new World. Globus Cassus' equator zones are equipped with a system of trenches and moulds that will become rivers, lakes and seas as soon as the water has settled. The transfer process of atmosphere and hydrosphere is called "The Great Rains".

Colonization
The moment the Great Rains start, the Earth becomes uninhabitable. Along with massive amounts of seed for all existing plants, the regions of high cultural value, that need to be conserved and reapplied on Globus Cassus have been stored in the skeleton nodes which touch the towers. Humans and animals rise in the towers to await the end of the rains and start settling on the two equator regions.

Plant growth
The remaining Earth core is dismantled to build the shells that lie in the pole regions. During this process, the massive heat radiation of the core accelerates plant growth and therefore aids the process of establishing a functioning biosphere.

Feasibility
There are many insurmountable problems associated with a project such as this.

The largest structure that could be built using known materials is no more than two thousand kilometers in diameter, using carbon nanotube fibre. A rotating habitat of steel as suggested in the 'Globus Cassus' concept, spun to produce Earth-like gravity, would fall apart if it were more than about 20 kilometers in diameter. Furthermore, the tidal forces exerted on the Globus Cassus by the sun and the moon would tear it apart while construction was underway.

Being at geostationary orbit, the equatorial regions of Global Cassus would have, in the absence of Earth's mass below, an artificial gravity equal to roughly 2% of normal Earth gravity. The same would hold in the archival nodes. Human beings and animals could not survive indefinitely in such microgravity, nor would this be sufficient to sustain a habitable atmospheric pressure.

Finally, the timescales required for construction of such a structure are of the order of millions of years.

Literature
Globus Cassus, Lars Müller Publishers, with contributions by Boris Groys, Claude Lichtenstein, Michael Stauffer and Christian Waldvogel. Awarded the Gold Medal in international competition "Best designed books from all over the World 2004", (ISBN 3-03778-045-2)