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30-421: A Dyson sphere is a hypothetical megastructure that encompasses a star and captures a large percentage of its power output . 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

60-543: A Dyson swarm ; however, in 2013, Dyson said he had come to regret that the concept had been named after him. 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. This could indicate

90-422: A continuous shell around the star in question, although Dyson himself considered that prospect to be mechanically implausible. They are sometimes used as the type of plot device known as a Big Dumb Object . 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. Dyson spheres are depicted in

120-761: A critique of SETI in the May 2012 Journal of the British Interplanetary Society (JBIS) arguing that SETI techniques and practices have become outdated. In its place, Dvorsky, Ćirković, and Bradbury advocated for what they called Dysonian SETI, namely the search for those signatures and artefacts indicative of highly advanced extraterrestrial life. Dvorsky has written extensively in favor of space exploration and has both promoted and criticized various Megascale engineering concepts. Dvorsky gained some notoriety in 2012 after writing about Dyson spheres , hypothetical structures intended to collect

150-444: A similar scale: A number of structures have appeared in fiction which may be considered megastructures. George Dvorsky Dvorsky is a secular Buddhist , progressive environmentalist, ancestral health advocate, and animal rights activist. Primarily concerned with the ethical and sociological impacts of emerging technologies , specifically, " human enhancement " technologies; he seeks to promote open discussion for

180-430: 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." Such a concept has often been referred to as

210-501: 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. 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. A precursor to

240-437: Is capable of "unlimited" extension. This type of framework allows the structure to adapt to the individual wishes of its residents, even as those wishes change with time. Other sources define a megastructure as "any development in which residential densities are able to support services and facilities essential for the development to become a self-contained community". Many architects have designed such megastructures. Some of

270-526: 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. 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

300-517: The 1960s where a city could be encased in a single building, or a relatively small number of buildings interconnected. Such arcology concepts are popular in science fiction . Megastructures often play a part in the plot or setting of science fiction movies and books, such as Rendezvous with Rama by Arthur C. Clarke . In 1968, Ralph Wilcoxen defined a megastructure as any structural framework into which rooms, houses, or other small buildings can later be installed, uninstalled, and replaced; and which

330-529: 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. In the 1992 episode " Relics " of the TV show Star Trek: The Next Generation , the USS ; Enterprise finds itself trapped in an abandoned Dyson Sphere; in a 2011 interview, Dyson said that he enjoyed the episode, although he considered

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360-640: The Dyson Sphere concept include a single circular band in Larry Niven 's 1970 novel Ringworld , a half sphere in the 2012 novel Bowl of Heaven by Gregory Benford and Niven, and nested spheres – also known as a Matrioshka brain  – in Colin Kapp 's 1980s Cageworld series and Brian Stableford 's 1979–1990 Asgard trilogy . Stableford himself observed that Dyson spheres are usually MacGuffins or largely deep in

390-491: 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. Some have suggested that Dyson sphere habitats could be built around white dwarfs and even pulsars . Stellar engines are hypothetical megastructures whose purpose

420-419: 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.He 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

450-653: The black? At one AU – which is the distance of the orbit of the Earth, the Sun emits 1.4 x 10 J/sec per square meter. That’s 1.4 x 10 J/sec per square kilometer. At one-third efficiency, that’s 4.67 x 10 J/sec for the entire Dyson sphere. That sounds like a lot, right? But here’s the thing – if you work it out, it will take 4.28 x 10 seconds for the solar collectors to obtain the energy needed to dismantle Mercury. That’s about 120 trillion years. Other publications including Popular Science , Vice , and skeptical blog Weird Things followed up on this exchange. None of them note

480-424: The concept of Dyson spheres was featured in the 1937 novel Star Maker by Olaf Stapledon , in which he described "every solar system... surrounded by a gauze of light-traps, which focused the escaping solar energy for intelligent use"; Dyson got his inspiration from this book and suggested that "Stapledon sphere" would be a more apt name for the concept. Fictional Dyson spheres are typically solid structures forming

510-581: 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. Dyson did not detail how such

540-593: The entire energetic output of a star with solar power collectors. While Dvorsky presented it as a solution to humanity's resource needs including power and living space, Forbes blogger Alex Knapp and astronomer Phil Plait , among others, have criticized Dvorsky's article. Dismantling Mercury, just to start, will take 2 x 10 joules, or an amount of energy 100 billion times the US annual energy consumption ... [Dvorsky] kinda glosses over that point. And how long until his solar collectors gather that much energy back, and we’re in

570-708: The first published article in defence of the Ashley Treatment in November 2006, and subsequently the only bioethicist cited by Ashley X 's parents in their defense. Dvorsky also presented an argument warning of the decline of democratic values and institutions in the face of existential and catastrophic risks at the Global Catastrophic Risks: Building a Resilient Civilization conference in November 2008. Dvorsky, along with Milan M. Ćirković and Robert Bradbury, published

600-418: The interior surface, which then leads to the problem of a gravity gradient that goes to zero at the rotational poles. 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 "). Megastructure A megastructure is a very large artificial object, although

630-602: 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. Most megastructure designs could not be constructed with today's level of industrial technology. This makes their design examples of speculative (or exploratory) engineering . Those that could be constructed easily qualify as megaprojects . Megastructures are also an architectural concept popularized in

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660-476: 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

690-693: The more notable such architects and architectural groups include the Metabolist Movement , Archigram , Cedric Price , Frei Otto , Constant Nieuwenhuys , Yona Friedman , and Buckminster Fuller . A number of theoretical structures have been proposed which may be considered megastructures. Most stellar scale megastructure proposals are designs to make use of the energy from a sun-like star while possibly still providing gravity or other attributes that would make it attractive for an advanced civilization. Related structures which might not be classified as individual stellar megastructures, but occur on

720-512: 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. Inspired by the 1937 science fiction novel Star Maker by Olaf Stapledon , 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

750-482: The presence of what has been called a Type   II Kardashev civilization . SETI has looked for such infrared-heavy spectra from solar analogs , as has Fermilab . Fermilab discovered 17 potential "ambiguous" candidates, of which four were in 2006 called "amusing but still questionable". Later searches also resulted in several candidates, all of which remain unconfirmed. On 14 October 2015, Planet Hunters ' citizen scientists discovered unusual light fluctuations of

780-579: The purposes of education and foresight . He writes and speaks on a wide range of topics, including technoscience , ethics , existential risks , artificial intelligence , the search for extraterrestrial intelligence , and futurology , from a democratic transhumanist perspective. Dvorsky presented an argument for non-human animal biological uplift at the IEET Human Enhancement Technologies and Human Rights conference at Stanford University in May 2006; and wrote

810-571: The sphere depicted to be "nonsense". 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. 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 . Variations on

840-434: 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. 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

870-422: The star KIC 8462852 raising press speculation that a Dyson sphere may have been discovered. However, subsequent analysis showed that the results were consistent with the presence of dust.A further campaign in 2024 identified seven possible candidates for Dyson-spheres, but further investigation was said to be required. Although Dyson sphere systems are theoretically possible, building a stable megastructure around

900-452: The surface of any orbiting planet , building structures encircling a star would enable a civilization to harvest far more energy. 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

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