Dyson Spheres

Dyson Spheres

While the National Aeronautics and Space Administration (NASA) considers future human trips to Mars and continues to build the International Space Station, some individuals in the field have pushed for even more. They believe that the key to human expansion in space does not lie in the building of colonies on planets or even the building of small space stations . Scientists such as Freeman Dyson and Gerard K. O'Neill proposed building gigantic structures for humans to live in. What makes their ideas even more unconventional is the size of their proposed structures. The structures proposed by O'Neill, known as O'Neill colonies, could be a dozen miles long and a few miles wide. Freeman Dyson's structures, called Dyson Spheres or Dyson Shells, would be the size of a planet's orbit. While it would only be a few meters thick, the size of the sphere would stretch for millions of miles.

Dyson's Vision

In 1959 Dyson hatched the idea of building a huge sphere around a star. In his theory, a shell built at a safe distance away from the star would allow billions of people to live inside while allowing the civilization to harness a large amount of energy, in the form of radiation, from the star. While his vision is fascinating, it poses concerns.

One concern that needs to be addressed involves the materials that could be used to build such a structure. Not only would the shell need to stay together, but it would have to absorb impacts without the inertia pushing it into the star. Creating gravity would be a problem, since spinning the sphere would add more stress to the structure and force everyone to the equator of the sphere. Moreover, the amount of raw materials needed to create a space that would be one billion times bigger than the Earth is enormous. Future engineers would need to be able to deconstruct and process other planets and asteroids to create a sphere.

The Search for Dyson Spheres

Searches have been conducted using radio telescopes to see if there may be Dyson Spheres already in existence, but none have yet been found. Due to the high level of technical expertise required to build a sphere of this magnitude, some scientists question Dyson's theories. Dyson responds that advanced civilizations would have the ability to build such a device, and that we cannot be biased by our current technological level:

One should expect that, within a few thousand years of its entering the stage of industrial development, any intelligent species should be found occupying an artificial biosphere which completely surrounds its parent star.

One type of colony Dyson suggested was the "Island Three." This design was an enormous cylinder that was twenty miles long and four miles across. The cylinder would spin to create artificial gravity, but spun slowly enough to prevent harmful G forces . The cylinder was designed to contain spaces for agriculture, industrial facilities, and even a place for ships to dock as they transported people from Earth. The Island Three was even designed with huge adjustable mirrors that would move to reflect the light of the Sun to create a daytime and nighttime for the inhabitants of the colony. This design would be capable of holding several million colonists, but not as many as a Dyson Sphere.

Not all proposed Dyson Spheres would need to be complete enclosures. It has been proposed that a smaller series of solar energy collectors could suffice as a first step towards the building of a Dyson Sphere. The collectors would be much larger than standard solar panels, and would therefore allow for a much greater energy gain. In the future, larger solar panels will be useful for extraterrestrial colonization.

see also Dyson, Freeman John (volume 4); L-5 Colonies (volume 4); O'Neill Colonies (volume 4).

Craig Samuels

Bibliography

Dyson, Freeman J. Disturbing the Universe. New York: Basic Books, 2001.

O'Neill, Gerard K. High Frontier: Human Colonies in Space. Burlington, Ontario, Canada: Collector's Guide Publishing, Inc., 2000.

Internet Resources

What's a Dyson Sphere? Astronomy Frequently Asked Questions. <http://www.faqs.org/faqs/astronomy/faq/part6/section-13.html>.