Searching for Dyson Spheres

For centuries, the subject of extraterrestrial intelligence has captivated the minds of the writer and the scientist alike. But, how do we find extraterrestrial intelligence? We could wait to receive a message in a bottle-by detecting radio waves, which float through vast regions of space and time. That is the traditional approach in radioastronomy, one to which SETI suscribed. But perhaps we could take a more creative and active approach by trying to predict other detectable signs of intelligence. That's where Dyson Spheres come in.

Dyson Spheres are hypothetical mega-systems which surround a star in order to absorb energy. Think of it as a curved array of solar panels with the sun in the center, except that the panel units could be composed of many individual satellites, called "Dyson Rings", or take a solid "shell-like" structure which make up the sphere. When Dysonian energy extraction methods are used, the light emitted from the star would be altered in predictable ways as the energy absorbed by a Dyson sphere is reradiated at a lower temperature; Dyson suggested looking for radiation in the deep infrared.

First dreamt of in a 1960 thought-experiment by physicist and mathematician Freeman Dyson, this curious little thought just might help us provide insight into one of mankind's ultimate questions-whether or not humanity is alone in the universe.

For us to detect an extraterrestrial civilization, they would almost certainly need to have tools and machines. Technological civilizations, by default, require the extraction of energy from their external environment-it is the unavoidable cost of mechanized society. For humanity, this power-scouting enterprise has, for the most part, involved finding the remains of dead plant and animal matter and then releasing the energy stored within these former denizens of the Earth. This can only last for so long before the supply extinguishes, or the demand for energy exponentially overtakes the available supply on the planet. If this happens, the logical consequence would be to look for energy supplies beyond the planetary realm. This is the hypothetical sequence of events Dyson formulated in his eponymous 1960 paper to Science, which has gone to influence fiction authors, scientists, filmmakers, and video game developers since. (Perhaps you might be familiar with Dyson-sphere inspired appearances in the show Star Trek: The Next Generation, and in the popular game, Halo.)

Now, after a civilization grows beyond the point that its own planet can sustain its energy requirements, Dyson suggested that they would naturally seek to harness the tremendous power of a conveniently nearby stellar source. When thinking about extraterrestrial intelligence, we should keep these two assumptions about them, which are implied in Dyson's thought experiment:

1. The growth of civilizations is exponential or increases enough over time to necessitate tremendous power demands.

2. Civilizations reach a sufficient level of technological advancement to supply their needs, if it is mechanically feasible at all.

This makes Dyson-spheres a potentially likely occurrence in very advanced societies. With this in mind, we can supplement our cosmic search efforts by looking for the power-plant smoke signals that is altered infrared radiation. The search for extraterrestrial life using these stellar indicators is also less presuming. It does not assume that extraterrestrial intelligence is trying to communicate, merely that they would attempt to utilize a likely source for energy. Not a terrible assumption!

Though it is true that search methods could be expanded, the concept of Dyson spheres is still very much speculative and hypothetical. Dyson himself, in an interview, later said that the whole idea was a little joke that he did not take seriously. Yet, it remains powerful enough a thought-experiment to influence the search for extraterrestrial intelligence, which is in itself a hypothetical assumption. It is not so unreasonable that speculative assumptions ask for speculative methods for their validation.

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Image credits:

Figure 1 (top): Bardon (From Eso/Z)

Figure 2: (Via Wikipedia)

References:

1. Dyson. F. Search for Artificial Stellar Sources of Infrared Radiation. Science. 131, 1667-1668 (1963).

2. Anderson, R. "The Best Way to Find Aliens: Look for Their Solar Power Plants." The Atlantic. (2012).

3. Meaningoflifetv. Dyson Transcript.