Search For Extra-terrestrial Intelligence
In Dyson's original paper, he speculated that sufficiently advanced extraterrestrial civilizations would likely follow a similar power consumption pattern as humans, and would eventually build their own sphere of collectors. Constructing such a system would make such a civilization a Type II Kardashev civilization.
The existence of such a system of collectors would alter the light emitted from the star system. Collectors would absorb and reradiate energy from the star. The wavelength(s) of radiation emitted by the collectors would be determined by the emission spectra of the substances making them up, and the temperature of the collectors. Since it seems most likely that these collectors would be made up of heavy elements not normally found in the emission spectra of their central star–or at least not radiating light at such relatively "low" energies as compared to that which they would be emitting as energetic free nuclei in the stellar atmosphere–there would be atypical wavelengths of light for the star's spectral type in the light spectrum emitted by the star system. If the percentage of the star's output thus filtered or transformed by this absorption and reradiation was significant, it could be detected at interstellar distances.
Given the amount of energy available per square meter at a distance of 1 AU from the Sun, it is possible to calculate that most known substances would be reradiating energy in the infrared part of the electromagnetic spectrum. Thus, a Dyson Sphere, constructed by life forms not dissimilar to humans, who dwelled in proximity to a Sun-like star, made with materials similar to those available to humans, would most likely cause an increase in the amount of infrared radiation in the star system's emitted spectrum. Hence, Dyson selected the title "Search for Artificial Stellar Sources of Infrared Radiation" for his published paper.
SETI has adopted these assumptions in their search, looking for such "infrared heavy" spectra from solar analogs. As of 2005 Fermilab has an ongoing survey for such spectra by analyzing data from the Infrared Astronomical Satellite (IRAS). Identifying one of the many infra-red sources as a Dyson Sphere would require improved techniques for discriminating between a Dyson Sphere and natural sources. Fermilab discovered 17 potential "ambiguous" candidates of which four have been named "amusing but still questionable". Other searches also resulted in several candidates, which are however unconfirmed.
Read more about this topic: Dyson Sphere
Famous quotes containing the words search for, search and/or intelligence:
“At any age we must cherish illusions, consolatory or merely pleasant; in youth, they are omnipresent; in old age we must search for them, or even invent them. But with all that, boredom is their natural and inevitable accompaniment.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)
“His life itself passes deeper in nature than the studies of the naturalist penetrate; himself a subject for the naturalist. The latter raises the moss and bark gently with his knife in search of insects; the former lays open logs to their core with his axe, and moss and bark fly far and wide. He gets his living by barking trees. Such a man has some right to fish, and I love to see nature carried out in him.”
—Henry David Thoreau (1817–1862)
“But as these angels, the only halted ones
among the many who passed and repassed,
trod air as swimmers tread water, each gazing
on the angelic wings of the other,
the intelligence proper to great angels flew into their wings,
the intelligence called intellectual love....”
—Denise Levertov (b. 1923)