Alderson disk
An Alderson disk[1][2] (named after Dan Alderson, its originator) is a hypothetical artificial astronomical megastructure, like Larry Niven's Ringworld and the Dyson sphere. The disk is a giant platter with a thickness of several thousand miles. The Sun rests in the hole at the center of the disk. The outer perimeter of an Alderson disk would be roughly equivalent to the orbit of Mars or Jupiter. According to the proposal, a sufficiently large disk would have a larger mass than its Sun.
The hole would be surrounded by a thousand-mile-high wall to prevent the atmosphere from drifting into the Sun.[3] The outer rim would not require a wall.
The mechanical
Life could exist on either side of the disk, though close to the Sun the heat would make life impossible without protection. Conversely, farther away from the Sun living beings would freeze. Therefore, for the entirety of such a structure to be made habitable, it would have to include a vast number of life support systems. Even without such systems, the habitable surface area would be an equivalent of tens to hundreds of millions of Earths.
Because the Sun remains stationary, there is no day/night cycle, only a perpetual twilight. This could be solved by forcing the Sun to bob up and down within the disk, lighting first one side then the other.[5]
In popular culture
In 1974, the science fiction writer Larry Niven suggested that an Alderson disk "would be a wonderful place to stage a gothic or sword and sorcery novel. The atmosphere is right, and there are real monsters." Because the zone habitable by humans is 'relatively narrow' (5% closer in and farther out than Earth's current orbit would provide 50 million times the surface area of Earth), the disc (and the cost of its construction) could be shared with aliens from hotter and colder planets. Over long periods of time, lifeforms would evolve to settle the sparsely-inhabited regions in between. "If civilization should fall, things could get eerie and interesting."[5]
An Alderson disk (the Godwheel) was a prominent feature of
Rak Mesba is a partial ancient alien Alderson Disk in
A disk-shaped planet similar to an Alderson disk (though far smaller) served as the homeworld of the fantasy "Aysle" setting (or "cosm") of
In Charles Stross's Missile Gap, a copy of the whole Earth (along with copies of many other planets) is placed on an Alderson disk built around a black hole by unknown forces.
In Terry Pratchett's science fiction novel Strata the concept of an Alderson disk is brought up by the protagonist, Kin Arad, as an explanation for the mysterious 'flat earth' that is the focus of the story.
In Gigastructural Engineering & More, a popular modification to the 4X game Stellaris, the Alderson Disk is featured as a buildable megastructure inhabitable by the player.
In the game Honkai: Star Rail, the planet of Penacony is actually a large artificial space station-like megastructure housing a hotel surrounded by two small Alderson disks orbiting it.
See also
- Dyson sphere – Hypothetical megastructure around a star
- Dyson tree – Hypothetical genetically-engineered plant capable of growing inside a comet
- Globus Cassus – Art project and book by Christian Waldvogel
- Kardashev scale – Measure of a civilization's evolution
- Klemperer rosette – Type of gravitational system
- Matrioshka brain – Huge computer powered by a star's energy
- Megascale engineering – Form of exploratory engineering
- Planetary engineering – Influencing a planet's global environments
- Ringworld – 1970 science fiction novel by Larry Niven
- Star lifting – Hypothetical process of mining a star for resources
- Stellar engineering – Hypothetical artificial modification of stars
- Tabby's Star – Star noted for unusual dimming events
- Tensegrity – Structural design made of isolated members held in place by tension
- Terraforming – Hypothetical planetary engineering process
References
- ^ Hadhazy, Adam (5 August 2014). "Could We Build a Disk Bigger Than a Star?". Popular Mechanics. Retrieved 23 December 2016.
- ISBN 978-1491850145– via Google Books.
- ^ Adam Hadhazy (August 4, 2014). "Could We Build a Disk Bigger Than a Star?". Popular Mechanics. Retrieved April 2, 2023.
- ^ Matthew S. Williams (March 10, 2019). "Megastructures – A Sign of Larger than Life Aliens?". interestingengineering.com. Retrieved April 2, 2023.
- ^ ISBN 0345240111. This essay was first published in Analog magazine (1974), and is also anthologised in Playgrounds of the Mind.
- ^ Radtech497 (10 December 2010). "Rak Mesba". Encyclopedia Galactica. Orion's Arm Universe Project. Retrieved 2019-06-20.
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