Editing Bernal sphere

{{Short description|Long-term space habitat proposal}}
{{for|fictional structures for living in space|Space stations and habitats in fiction}}
[[Image:External view of a Bernal sphere.jpg|thumb|upright=1.4|Exterior of a Bernal sphere]]
[[File:Bernal sphere interior.jpg|thumb|upright=1.4|Interior of a Bernal sphere]]
A '''Bernal sphere''' is a type of [[space settlement]] intended as a long-term home for permanent residents, first proposed in 1929 by [[John Desmond Bernal]].

Bernal's original proposal described a hollow non-rotating spherical shell {{convert|10|mi|km|abbr=on}} in diameter, with a target population of 20,000 to 30,000 people. The Bernal sphere would be filled with [[Earth's atmosphere|air]].<ref>{{cite book|last=Bernal|first=John Desmond|title=The World, the Flesh and the Devil|year=1929|url=http://bactra.org/Bernal/}}</ref>

==O'Neill versions==
===Island One===
[[File:Bernal sphere space habitat - O Neill Island One version.png|thumb|upright=3.8|Example layout for an Island One-type Bernal sphere]]
In a series of studies held at [[Stanford University]] in 1975 and 1976 with the purpose of speculating on designs for future [[space colonies]], Dr. [[Gerard K. O'Neill]] proposed ''Island One,'' a modified Bernal sphere with a diameter of only {{convert|500|m|ft|abbr=on}} rotating at 1.9 [[Revolutions per minute|RPM]]<!--faster was found to create difficulties with balance--> to produce a full [[Earth]] [[artificial gravity]] at the sphere's equator. The result would be an interior landscape that would resemble a large valley running all the way around the [[equator]] of the sphere. ''Island One'' would be capable of providing living and recreation space for a population of approximately 10,000 people, with a "Crystal Palace" habitat (consisting of several rings attached to the sphere at each pole) used for agriculture. Sunlight was to be provided to the interior of the sphere using external [[mirror]]s to direct it in through large windows near the poles. The form of a sphere was chosen for its optimum ability to contain air [[pressure]] and its optimum mass-efficiency at providing [[radiation shielding]].<ref name="ONeill" >{{cite book |last=O'Neill |first=Gerard K. |title=[[The High Frontier: Human Colonies in Space]] |edition=Third |publisher=[[Apogee Books]] |year=2000}}</ref>

===Island Two===
O'Neill envisioned the next generation of space habitat as a larger version of ''Island One''. ''Island Two'' would be approximately 1800 meters in diameter, yielding an equatorial circumference of nearly six and a half kilometers (four miles). The size was driven by economics; the habitat was to be small enough to allow for efficient transportation within the habitat and large enough to support an efficient industrial base.<ref name="ONeill"/>{{rp|93}}

==Image gallery==
<gallery heights='200' widths='260'>
File:Bernal Sphere 2.jpeg|The inside of the sphere as viewed from the sunlight "portal"
File:Bernal Sphere agricultural module.jpeg|Agricultural module of a Bernal sphere
File:External view of a Bernal sphere 2.jpg|Exterior of a Bernal sphere
File:Solar power satellite from an asteroid.jpg|A Bernal sphere next to a [[solar power satellite]] and an [[asteroid mining]] station
</gallery>

==In popular culture==
* The video game ''[[Sonic Adventure 2]]'' features a fictional Bernal sphere space colony called "ARK". In this colony, [[Doctor Eggman]]'s grandfather (The [[List of recurring characters from Sonic the Hedgehog (games)#Professor Gerald Robotnik|Professor Gerald Robotnik]]) created [[Shadow the Hedgehog]] to cure his granddaughter [[List of recurring characters from Sonic the Hedgehog (games)#Maria Robotnik|Maria]]'s illness, but the Guardians Units of Nations (G.U.N.) considered Shadow as a threat, so they shut down the space colony and neutralized everyone who knew about Shadow, including Maria, who died trying to protect him. A mistranslation in the English dub of ''Sonic Adventure 2'' has [[Tails (Sonic the Hedgehog)|Tails]] incorrectly refer to the ARK as a "[[Daniel Bernoulli|Bernoulli]] spherical space colony".
* In the setting of the anime television series ''[[Mobile Suit Gundam 00]]'', space colonies are based on underdeveloped technology, and only small-sized colonies, such as the Bernal sphere-shaped "Quanqiu" located in Lagrange 3, make an appearance.
* In the anime television series ''[[Mobile Suit Gundam ZZ]],'' the space colony Moon Moon is a Bernal sphere.
* The video game ''[[Mass Effect]]'' features a fictional Bernal sphere space colony "Gagarin Station," named after [[Yuri Gagarin]].

==See also==
* [[Dyson sphere]]
* [[Space habitat]]
** [[O'Neill cylinder]] aka ''Island III'', the brother design to ''Island I''
** [[Rotating wheel space station]]
** [[Space stations and habitats in popular culture#Bernal spheres|Bernal sphere in popular culture]]
** [[Stanford torus]]
* [[Space colonization]]

==References==
{{reflist}}

==External links==
{{Commons category|Bernal sphere}}
*[http://settlement.arc.nasa.gov/75SummerStudy/Design.html NASA SP-413: Space Settlements – A Design Study.]
*[https://thescience360.com/exploring-the-bernal-sphere-a-revolutionary-concept-for-space-colonization/ Exploring the Bernal Sphere: A Revolutionary Concept for Space Colonization]
*{{Webarchive|url=https://web.archive.org/web/20181113083412/https://settlement.arc.nasa.gov/75SummerStudy/Design.html |date=2018-11-13 }}

{{Space stations}}

[[Category:Proposed space stations]]
[[Category:Space habitats]]