Dyson Sphere Engineering updated Dec. 15, 2010 D. Carrigan carrigan@fnal.gov (subject line must be sensible)

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Energy to assemble

An objection to the Dyson Sphere concept is the large energy required to assemble a sphere. Dyson states that his model case would require the output of the Sun for 800 years. Note that a ring (often called a “Ringworld” from the science fiction novels of L. Niven) would require less energy to assemble but would also not be as effective at collecting stellar energy. Seen through the ring a ringworld could shield the host star like a Dyson sphere. Viewed perpendicular to the ring plane it would not have a strong signature.

Nature of a Dyson Swarm

Finally, a non-anthropocentric view is helpful in considering the possible nature of Dyson’s swarm. The schematic shows a visualization due to Guillermo Lemarchand. The actual shell might be something like the shards of a broken-up planet, say a shell filled with a swarm of constantly-renewing 100 micron thick solar photocells powering silicon cell phone chips.

Rigid sphere?

There has been a great deal of informal discussion about the engineering of Dyson Spheres as well as Dyson Sphere generalizations sometimes called Astroengineering Constructions or AC. A putative shell formed from Earth at Earth’s distance from the Sun would be 4 mm thick, while a shell formed from Jupiter would be 5 m thick at Earth’s radius and 0.2 m thick at Jupiter’s distance from the Sun.

In the correspondence in Science Magazine in July 22, 1960 following Dyson’s article several writers drew attention to problems associated with constructing a sphere, in particular a rigid sphere. Dyson responded that a rigid sphere was impossible and that what he had in mind was a swarm of objects. For this article the word “sphere” is used to designate any assembly including rings.