---
title: "Dyson sphere"
chunk: 1/2
source: "https://en.wikipedia.org/wiki/Dyson_sphere"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:39:00.169646+00:00"
instance: "kb-cron"
---

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 the surface of any orbiting planet, building structures encircling a star would enable a civilization to harvest far more energy.
The earliest modern imagining of such a structure was by Olaf Stapledon in his science fiction novel Star Maker (1937). The same concept was later used by 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 Dyson himself  considered impossible. The sphere he imagined consisted of a loose collection or swarm of objects traveling on independent orbits around the star, an arrangement that has become known as a Dyson swarm.

== Origins ==

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 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 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 a "Dyson swarm"; however, in 2013, Dyson said he had come to regret that the concept had been named after him. In an interview with Robert Wright in 2003, Dyson referred to his paper on the search for Dyson spheres as "a little joke" and commented that "you get to be famous only for the things you don't think are serious", later explaining that "And of course the joke is that the sky is crawling with infrared sources which look just the way a Type II civilization might look, so there is absolutely no reason to believe that they are artificial ... from our distance they would look the same". However, in a later interview with students from The University of Edinburgh in 2018, he referred to the premise of the Dyson sphere as being "correct and uncontroversial". In other interviews, while lamenting the naming of the object, Dyson commented that "the idea was a good one", and referred to his contribution to a paper on disassembling planets as a means of constructing one.

== 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. This could indicate 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 October 14, 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. However, subsequent analysis showed that the results were consistent with the presence of dust. In 2024 there was press speculation that potential signs of interstellar Dyson spheres had been discovered.  The seven objects of interest – all located within a thousand light-years of Earth – were 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 explanations included a suggestion that the detected infrared was caused by distant dust-obscured galaxies.