For over 50 years, man has been searching for alien civilizations by way of a program known as the Search for Extraterrestrial Intelligence (SETI), whose singular focus has been on a search for radio waves emitted by a technically-advanced alien civilization. So far, SETI has come up empty. Now, though, a bold new idea on how to look for alien civilizations has been proposed: a search for heat signatures.
Theoretical physicist and mathematician Freeman Dyson once proposed that alien civilizations, with their technology far in advance of anything imaginable for us here on Earth, could build structures around their star or even galaxy in order to harvest the stellar energy. As is here on Earth, energy usage gives off heat, which is exactly the strategy Dyson proposes to look for alien civilizations: look for their heat signature.
How credible is the idea? Credible enough for scientists at Pennsylvania State University (PSU) to start scanning the sky in the infrared to look for such heat signatures, thus getting around a limitation of all past SETI searches, which focused completely on radio waves.
Commenting further on his theory, Dyson is quick to clear up one popular misconception: that a Dyson Sphere is exactly that: a giant spherical structure built around a star. In contrast, Dyson says that his 'sphere' is merely an artificial biosphere, wherein several objects could be placed in planetary/stellar orbit in order to harvest energy.
Doing some calculations, Dyson came to the conclusion that an alien civilization with a surface temperature of about 80 degrees Fahrenheit would give off infrared radiation with wavelengths of 10 microns. The implication: to find Dyson Spheres, one needs to scan the sky for infrared radiation with a wavelength of 10 microns.
Now for the search: a hunt for Dyson Spheres harvesting energy on the galactic scale, which is exactly what Jason Wright of PSU has decided to do. Using data from the Wide Field Infrared Survey Explorer (WISE) observatory, Wright and his team will look for infrared signatures in the data that could represent solar energy harvesting on, for us here on Earth, an unimaginably large scale. If any possible Dyson candidates are found, these observations will be examined more closely with other telescopes.
However, this is not a first of its kind search.
Richard Carrigan, scientist emeritus at Fermilab, has also looked for the hypothetical Dyson Spheres on the stellar scale by analyzing information from the Infrared Astronomical Satellite (IRAS), which maps the entire sky in the infrared. Result: after a systematic search, Carrigan only found a couple of possible Dyson Spheres within a few hundred light years of Earth.
Are Dyson Spheres real? Would we be able to distinguish them from natural infrared radiation sources? Who knows, but one thing is certain: this is an experiment on the cutting-edge of science and one that deserves to to be undertaken.
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