A Bernal sphere is a type of space habitat intended as a long-term home for permanent residents, first proposed in 1929 by

John Desmond Bernal John Desmond Bernal (; 10 May 1901 – 15 September 1971) was an Irish scientist who pioneered the use of X-ray crystallography in molecular biology. He published extensively on the history of science. In addition, Bernal wrote popular book ...

. Bernal's original proposal described a hollow non-rotating spherical shell in diameter, with a target population of 20,000 to 30,000 people. The Bernal sphere would be filled with

air The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing f ...

O'Neill versions

Island One

In a series of studies held at

Stanford University Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is consider ...

in 1975 and 1976 with the purpose of speculating on designs for future

space colonies Space colonization (also called space settlement or extraterrestrial colonization) is the use of outer space or celestial bodies other than Earth for permanent habitation or as extraterrestrial territory. The inhabitation and territoria ...

, Dr.

Gerard K. O'Neill Gerard Kitchen O'Neill (February 6, 1927 – April 27, 1992) was an American physicist and space activist. As a faculty member of Princeton University, he invented a device called the particle storage ring for high-energy physics experiments. L ...

proposed ''Island One,'' a modified Bernal sphere with a diameter of only rotating at 1.9

RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines. Standards ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...

to produce a full

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

artificial gravity Artificial gravity is the creation of an inertial force that mimics the effects of a gravitational force, usually by rotation. Artificial gravity, or rotational gravity, is thus the appearance of a centrifugal force in a rotating frame of r ...

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 The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...

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 used for agriculture. Sunlight was to be provided to the interior of the sphere using external

mirror A mirror or looking glass is an object that Reflection (physics), reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the ...

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 Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

and its optimum mass-efficiency at providing

radiation shielding Radiation protection, also known as radiological protection, is defined by the International Atomic Energy Agency (IAEA) as "The protection of people from harmful effects of exposure to ionizing radiation, and the means for achieving this". Exposur ...

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.

Image gallery

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 Space-based solar power (SBSP, SSP) is the concept of collecting solar power in outer space by solar power satellites (SPS) and distributing it to Earth. Its advantages include a higher collection of energy due to the lack of reflection and ab ...

and an

asteroid mining Asteroid mining is the hypothetical exploitation of materials from asteroids and other minor planets, including near-Earth objects. Notable asteroid mining challenges include the high cost of spaceflight, unreliable identification of asteroids ...

station

References

External links