Dyson sphere

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A hypothetical depiction of a Dyson swarm surrounding a star Dyson Swarm realistic representation cropped.jpg
A hypothetical depiction of a Dyson swarm surrounding a star
Freeman Dyson, the first scientist to explore the concept Freeman dyson (detail).jpg
Freeman Dyson, the first scientist to explore the concept

A Dyson sphere is a hypothetical megastructure that encompasses a star and captures a large percentage of its power output. [1] [2] [3] The concept is a thought experiment that attempts to imagine how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet's resources alone. Because only a tiny fraction of a star's energy emissions reaches the surface of any orbiting planet, building structures encircling a star would enable a civilization to harvest far more energy.

Contents

The first modern imagining of such a structure was by Olaf Stapledon in his science fiction novel Star Maker (1937). The concept was later explored by the physicist Freeman Dyson in his 1960 paper "Search for Artificial Stellar Sources of Infrared Radiation". Dyson speculated that such structures would be the logical consequence of the escalating energy needs of a technological civilization and would be a necessity for its long-term survival. A signature of such spheres detected in astronomical searches would be an indicator of extraterrestrial intelligence.

Since Dyson's paper, many variant designs involving an artificial structure or series of structures to encompass a star have been proposed in exploratory engineering or described in science fiction, often under the name "Dyson sphere". Fictional depictions often describe a solid shell of matter enclosing a star an arrangement considered by Dyson himself to be impossible.

Origins

Inspired by the 1937 science fiction novel Star Maker by Olaf Stapledon, [4] the physicist and mathematician Freeman Dyson was the first to formalize the concept of what became known as the "Dyson sphere" in his 1960 Science paper "Search for Artificial Stellar Sources of Infra-Red Radiation". Dyson theorized that as the energy requirements of an advanced technological civilization increased, there would come a time when it would need to systematically harvest the energy from its local star on a large scale. He speculated that this could be done via a system of structures orbiting the star, designed to intercept and collect its energy. He argued that as the structure would result in the large-scale conversion of starlight into far-infrared radiation, an earth-based search for sources of infrared radiation could identify stars supporting intelligent life. [5]

Dyson did not detail how such a system could be constructed, simply referring to it in the paper as a "shell" or "biosphere". He later clarified that he did not have in mind a solid structure, saying: "A solid shell or ring surrounding a star is mechanically impossible. The form of 'biosphere' which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star." [6] Such a concept has often been referred to as a Dyson swarm; [7] however, in 2013, Dyson said he had come to regret that the concept had been named after him. [8]

Search for megastructures

Dyson-style energy collectors around a distant star would absorb and re-radiate energy from the star. The wavelengths of such re-radiated energy may be atypical for the star's spectral type, due to the presence of heavy elements not naturally occurring within the star. If the percentage of such atypical wavelengths were to be significant, an alien megastructure could be detected at interstellar distances. [5] This could indicate the presence of what has been called a Type II Kardashev civilization. [9]

SETI has looked for such infrared-heavy spectra from solar analogs, as has Fermilab. [10] [11] Fermilab discovered 17 potential "ambiguous" candidates, of which four were in 2006 called "amusing but still questionable". [10] Later searches also resulted in several candidates, all of which remain unconfirmed. [12] [13] [14]

On 14 October 2015, Planet Hunters' citizen scientists discovered unusual light fluctuations of the star KIC 8462852 raising press speculation that a Dyson sphere may have been discovered. [15] [16] However, subsequent analysis showed that the results were consistent with the presence of dust. [17] [18] A further campaign in 2024 identified seven possible candidates for Dyson-spheres, but further investigation was said to be required. [19] [20]

Feasibility and science-based speculation

Although Dyson sphere systems are theoretically possible, building a stable megastructure around the Sun is currently far beyond humanity's engineering capacity. The number of craft required to obtain, transmit, and maintain a complete Dyson sphere exceeds present-day industrial capabilities. George Dvorsky has advocated the use of self-replicating robots to overcome this limitation in the relatively near term. [21] Some have suggested that Dyson sphere habitats could be built around white dwarfs [22] and even pulsars. [23]

Stellar engines are hypothetical megastructures whose purpose is to extract useful energy from a star, sometimes for specific purposes. For example, Matrioshka brains have been proposed to extract energy for computation, while Shkadov thrusters would extract energy for propulsion. Some proposed stellar engine designs are based on the Dyson sphere. [24] [25]

From May until June 2024, speculation grew that potential signs of interstellar Dyson spheres had been discovered. The seven objects of interest all located within a thousand light-years of Earth are M-dwarfs, a class of stars that are smaller and less luminous than the Sun. However, the authors of the findings were careful not to make any overblown claims. [26] Despite this, many media outlets picked up on the story. Less fantastical alternative explanations have been made, including a proposal that the infrared from the discoveries was caused by distant dust-obscured galaxies. [27] [28] [29]

Fictional examples

A precursor to the concept of Dyson spheres was featured in the 1937 novel Star Maker by Olaf Stapledon, [1] in which he described "every solar system... surrounded by a gauze of light-traps, which focused the escaping solar energy for intelligent use"; [30] Dyson got his inspiration from this book and suggested that "Stapledon sphere" would be a more apt name for the concept. [31] Fictional Dyson spheres are typically solid structures forming a continuous shell around the star in question, although Dyson himself considered that prospect to be mechanically implausible. [2] [3] They are sometimes used as the type of plot device known as a Big Dumb Object. [32]

Dyson spheres appear as a background element in many works of fiction, including the 1964 novel The Wanderer by Fritz Leiber where aliens enclose multiple stars in this way. [1] [32] [33] Dyson spheres are depicted in the 1975–1983 book series Saga of Cuckoo by Frederik Pohl and Jack Williamson, and one functions as the setting of Bob Shaw's 1975 novel Orbitsville and its sequels. [2] [3] In the 1992 episode "Relics" of the TV show Star Trek: The Next Generation , [34] the USS Enterprise finds itself trapped in an abandoned Dyson Sphere; [35] [36] in a 2011 interview, Dyson said that he enjoyed the episode, although he considered the sphere depicted to be "nonsense". [37] Michael Jan Friedman who wrote the novelization observed that in the TV episode itself the Dyson sphere was effectively a MacGuffin, with "just nothing about it" in the story, and decided to flesh out the plot element in his novelization. [38] :ix

Other science-fiction story examples include Tony Rothman's The World Is Round, Somtow Sucharitkul's Inquisitor series, Timothy Zahn's Spinneret, James White's Federation World, Stephen Baxter's The Time Ships , and Peter F. Hamilton's Pandora's Star. [1] :133 Variations on the Dyson Sphere concept include a single circular band in Larry Niven's 1970 novel Ringworld , [3] [39] [40] a half sphere in the 2012 novel Bowl of Heaven by Gregory Benford and Niven, [2] [3] and nested spheres also known as a Matrioshka brain  in Colin Kapp's 1980s Cageworld series and Brian Stableford's 1979–1990 Asgard trilogy. [1] [3]

Stableford himself observed that Dyson spheres are usually MacGuffins or largely deep in the backgrounds of stories, giving as examples Fritz Leiber's The Wanderer and Linda Nagata's Deception Well, whereas stories involving space exploration tend to employ the variants like Niven's Ringworld. [1] :133He gives two reasons for this: firstly that Dyson spheres are simply too big to address, which Friedman also alluded to when pointing out that the reason his novelization of "Relics" did not go further into the sphere was that it was only four hundred pages and he had just shy of four weeks to write it; and secondly that, especially for hard science-fiction, Dyson spheres have certain engineering problems that complicate stories. [1] :133 [38] :ix In particular, since gravitational attraction is in equilibrium inside such a sphere (per the shell theorem), other means such as rotating the sphere have to be employed in order to keep things attached to the interior surface, which then leads to the problem of a gravity gradient that goes to zero at the rotational poles. [1] :133 Authors address this with various modifications of the idea such as the aforementioned Cageworld nesting, Dan Alderson's double sphere idea, and Niven's reduced Ringworld (discussed in "Bigger Than Worlds"). [1] :133

See also

Related Research Articles

<span class="mw-page-title-main">Freeman Dyson</span> British theoretical physicist and mathematician (1923–2020)

Freeman John Dyson was a British-American theoretical physicist and mathematician known for his works in quantum field theory, astrophysics, random matrices, mathematical formulation of quantum mechanics, condensed matter physics, nuclear physics, and engineering. He was professor emeritus in the Institute for Advanced Study in Princeton and a member of the board of sponsors of the Bulletin of the Atomic Scientists.

In discussion of science fiction, a Big Dumb Object (BDO) is any mysterious object, usually of extraterrestrial or unknown origin and immense power, in a story which generates an intense sense of wonder by its mere existence. To a certain extent, the term deliberately deflates the intended grandeur of the mysterious object.

<span class="mw-page-title-main">Kardashev scale</span> Measure of a civilizations evolution

The Kardashev scale is a method of measuring a civilization's level of technological advancement based on the amount of energy it is capable of harnessing and using. The measure was proposed by Soviet astronomer Nikolai Kardashev (1932–2019) in 1964 and was named after him.

<i>Star Maker</i> 1937 novel by Olaf Stapledon

Star Maker is a science fiction novel by British writer Olaf Stapledon, published in 1937. Continuing the theme of the author's previous book, Last and First Men (1930)—which narrated a history of the human species over two billion years—it describes a history of life in the universe, dwarfing the scale of the earlier work. Star Maker tackles philosophical themes such as the essence of life, of birth, decay and death, and the relationship between creation and creator. A pervading theme is that of progressive unity within and between different civilisations.

A matrioshka brain is a hypothetical megastructure of immense computational capacity powered by a Dyson sphere. It was proposed in 1997 by Robert J. Bradbury (1956–2011). It is an example of a class-B stellar engine, employing the entire energy output of a star to drive computer systems. This concept derives its name from the nesting Russian matryoshka dolls. The concept was deployed by Bradbury in the anthology Year Million: Science at the Far Edge of Knowledge.

<span class="mw-page-title-main">Alderson disk</span> Hypothetical artificial solar megastructure

An Alderson disk 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 more mass than its Sun.

Xenoarchaeology, a branch of xenology dealing with extraterrestrial cultures, is a hypothetical form of archaeology that exists mainly in works of science fiction. The field is concerned with the study of the material remains to reconstruct and interpret past life-ways of alien civilizations. Xenoarchaeology is not currently practiced by mainstream archaeologists due to the current lack of any material for the discipline to study.

<span class="mw-page-title-main">Megastructure</span> Very large artificial object

A megastructure 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 enormous self-supporting artificial construct. The products of megascale engineering or astroengineering are megastructures.

Megascale engineering is a form of exploratory engineering concerned with the construction of structures on an enormous scale. Typically these structures are at least 1,000 km (620 mi) in length—in other words, at least one megameter, hence the name. Such large-scale structures are termed megastructures.

<span class="mw-page-title-main">Stellar engine</span> Class of hypothetical megastructures

Stellar engines are a class of hypothetical megastructures which use the resources of a star to generate available work. For instance, they can use the energy of the star to produce mechanical, electrical or chemical work or they can use the impulse of the light emitted by the star to produce thrust, able to control the motion of a star system. The concept has been introduced by Bădescu and Cathcart. The variants which produce thrust may accelerate a star and anything orbiting it in a given direction. The creation of such a system would make its builders a type-II civilization on the Kardashev scale.

<span class="mw-page-title-main">Dyson tree</span> Hypothetical genetically-engineered plant capable of growing inside a comet

A Dyson tree is a hypothetical genetically engineered plant capable of growing inside a comet, suggested by the physicist Freeman Dyson. Plants may be able to produce a breathable atmosphere within the hollow spaces of the comet, utilising solar energy for photosynthesis and cometary materials for nutrients, thus providing self-sustaining habitats for humanity in the outer solar system analogous to a greenhouse in space, a shell grown by a mollusc or the actions of thermogenic plants, such as the skunk cabbage or the voodoo lily.

Stellar engineering is a type of engineering concerned with creating or modifying stars through artificial means.

<span class="mw-page-title-main">Stars in fiction</span>

Stars outside of the Solar System have been featured as settings in works of fiction since at least the 1600s, though this did not become commonplace until the pulp era of science fiction. Stars themselves are rarely a point of focus in fiction, their most common role being an indirect one as hosts of planetary systems. In stories where stars nevertheless do get specific attention, they play a variety of roles. Their appearance as points of light in the sky is significant in several stories where there are too many, too few, or an unexpected arrangement of them; in fantasy, they often serve as omens. Stars also appear as sources of power, be it the heat and light of their emanating radiation or superpowers. Certain stages of stellar evolution have received particular attention: supernovae, neutron stars, and black holes. Stars being depicted as sentient beings—whether portrayed as supernatural entities, personified in human form, or simply anthropomorphized as having intelligence—is a recurring theme. Real stars occasionally make appearances in science fiction, especially the nearest: the Alpha Centauri system, often portrayed as the destination of the first interstellar voyage. Tau Ceti, a relatively-nearby star regarded as a plausible candidate for harbouring habitable planets, is also popular.

<span class="mw-page-title-main">Black holes in fiction</span>

Black holes, objects whose gravity is so strong that nothing—including light—can escape them, have been depicted in fiction since at least the pulp era of science fiction, before the term black hole was coined. A common portrayal at the time was of black holes as hazards to spacefarers, a motif that has also recurred in later works. The concept of black holes became popular in science and fiction alike in the 1960s. Authors quickly seized upon the relativistic effect of gravitational time dilation, whereby time passes more slowly closer to a black hole due to its immense gravitational field. Black holes also became a popular means of space travel in science fiction, especially when the notion of wormholes emerged as a relatively plausible way to achieve faster-than-light travel. In this concept, a black hole is connected to its theoretical opposite, a so-called white hole, and as such acts as a gateway to another point in space which might be very distant from the point of entry. More exotically, the point of emergence is occasionally portrayed as another point in time—thus enabling time travel—or even an entirely different universe.

An infrared excess is a measurement of an astronomical source, typically a star, that in their spectral energy distribution has a greater measured infrared flux than expected by assuming the star is a blackbody radiator. Infrared excesses are often the result of circumstellar dust heated by starlight and reemitted at longer wavelengths. They are common in young stellar objects and evolved stars on the asymptotic giant branch or older.

Engineering on an astronomical scale, or astronomical engineering, i.e., engineering involving operations with whole astronomical objects, is a known theme in science fiction, as well as a matter of recent scientific research and exploratory engineering.

<span class="mw-page-title-main">Technosignature</span> Property that provides scientific evidence for the presence of technology

Technosignature or technomarker is any measurable property or effect that provides scientific evidence of past or present technology. Technosignatures are analogous to biosignatures, which signal the presence of life, whether intelligent or not. Some authors prefer to exclude radio transmissions from the definition, but such restrictive usage is not widespread. Jill Tarter has proposed that the search for extraterrestrial intelligence (SETI) be renamed "the search for technosignatures". Various types of technosignatures, such as radiation leakage from megascale astroengineering installations such as Dyson spheres, the light from an extraterrestrial ecumenopolis, or Shkadov thrusters with the power to alter the orbits of stars around the Galactic Center, may be detectable with hypertelescopes. Some examples of technosignatures are described in Paul Davies's 2010 book The Eerie Silence, although the terms "technosignature" and "technomarker" do not appear in the book.

"Bigger Than Worlds" is an essay by the American science fiction writer Larry Niven. It was first published in March 1974 in Analog magazine, and has been anthologized in A Hole in Space (1974) and in Playgrounds of the Mind (1991). It reviews a number of proposals, not inconsistent with the known laws of physics, which have been made for habitable artificial astronomical megastructures.

<i>Rendezvous with the Future</i> 2022 TV series or program

Rendezvous with the Future is a documentary series commissioned by Bilibili and produced by BBC Studios which explores the science behind the science fiction of author Liu Cixin. The series premiered in China on 16 November 2022 and has been watched by a combined audience of more than 85 million.

<span class="mw-page-title-main">Artificial planet</span> Proposed stellar megastructure

An artificial planet is a proposed stellar megastructure. Its defining characteristic is that it has sufficient mass to generate its own gravity field that is strong enough to prevent atmosphere from escaping, although the term has been sometimes used to describe other types of megastructures that have self-sufficient ecosystems. The concept can be found in many works of science-fiction.

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Further reading