AstroWeekly: The Dyson Sphere

The advancement of our species has largely hinged on our ability to harness more energy over time. Early energy provided by the control of fire was followed by the industrialization of our planet utilizing coal and oil/natural gas. Once we learned how to split an atom, atomic energy sourced from nuclear fission became possible (perhaps a form that has been underutilized), and we have since seen promising growth in the form of renewable energy sources like solar and wind. In the next few decades, we may see another transition to energy from nuclear fusion, and, assuming no planetary catastrophes, humanity will ultimately have complete control over Earth’s resources. Once this point is reached, we would hopefully begin expanding outward into space. However, extensive space exploration and solar system colonization both require immense amounts of energy that cannot be realistically obtained from a home base, so we must consider other sources. The ultimate solution to all energy needs would be the construction of what is known as a Dyson sphere.

Dyson spheres are hypothetical mega-engineering projects that would enable a species to capture a large proportion of their host star’s energy output. These structures were originally conceived and popularized as solid spheres that completely envelop a star, but more realistic and recent designs involve series of large, orbiting panels (“Dyson swarm”) that capture power from a star and beam it elsewhere. This would provide unlimited energy for the species that constructs it, but it would require massive amounts of material. Calculations show that to create a swarm around our own sun would require 30-quadrillion 1km x 1km panels, which sums to about 1x1020 tons of raw material. Once you add on the energy required to assemble and transport that much material, we are looking at a daunting task indeed. Some scientists have suggested the complete disassembly of the planet Mercury for these purposes, as it resides relatively close to the sun, is very rich in metals, has no atmosphere and has a force of gravitational pull about 1/3 that of Earth’s.

Building a Dyson sphere is far beyond our capabilities and will be for a long time, but it is entertaining to consider what will be necessary for our species to become one with a widespread presence in the solar system.