A shellworld is any of several types of hypothetical
megastructure
A megastructure (or macrostructure) is a very large artificial object, although the limits of precisely how large vary considerably. Some apply the term to any especially large or tall building. Some sources define a megastructure as an enorm ...
s:
*A planet or a planetoid turned into series of concentric
matryoshka doll-like layers supported by massive pillars.
A shellworld of this type features prominently in Iain M. Banks' novel ''
Matter
In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic pa ...
''.
*A megastructure consisting of multiple layers of shells suspended above each other by
orbital rings supported by hypothetical mass stream technology. This type of shellworld can be theoretically suspended above any type of stellar body, including planets, gas giants, stars and black holes. The most massive type of shellworld could be built around
supermassive black hole
A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...
s at the center of
galaxies.
*An inflated canopy holding high pressure air around an otherwise airless world to create a breathable atmosphere. The pressure of the contained air supports the weight of the shell. This type of structure could also be built on top of an existing smaller planet or asteroid, enabling it to support human-friendly atmosphere.
* Completely hollow shell worlds can also be created on a planetary or larger scale by contained gas alone, also called bubbleworlds, as long as the outward pressure from the contained gas balances the gravitational contraction of the entire structure, resulting in no net force on the shell. The scale is limited only by the mass of gas enclosed; the shell can be made of any mundane material. The shell can have an additional atmosphere on the outside.
See also
*
Artificial planet
References
External links
Shellworlds*
*
*
*{{cite web, url=http://www.orionsarm.com/eg-article/464f869fc12cb, title=Orion's Arm - Encyclopedia Galactica - Dynamic Orbital Rings, website=orionsarm.com, access-date=2018-08-09
Megastructures
Exploratory engineering
Terraforming