Infrared Astronomy:

Infrared astronomy is a burgeoning field with implications for many different areas of astronomy. One of the principal uses appears mudame at first, the search for cosmic dust. However it is this dust that gives birth to stars and provides clues about many aspects of the evolution of the Universe. We are each, after all, only cosmic dust cycled through several stars and loaned to our bodies for a mere one hundred millionth of the age of the universe. The Caltech/NASA site and the associated tutorial give some general background information on infrared and infrared astronomy. A good technical summary of dust in the Universe is Astrophysics of Dust, Volume CS-309, Editors: A. Witt, G. Clayton and B. Draine (2004), Astronomical Society of the Pacific.

Infrared astronomy is the key to looking for Dyson Spheres. The principal device used for the Dyson Sphere search at Fermilab has been the IRAS infrared satellite that flew in the mid eighties. The web link is listed below. Links to other related infrared facilities are also given.

In December, 2005 a Spitzer Space Telescope team announced the observation of some of the ingredients of life in a cloud around IRS 46. The Dyson Sphere search tools can be used to look for similar nearby objects.

Dyson Spheres:

In 1960 Dyson (Science 131, 1667 (1960)) suggested that an advanced civilization inhabiting a solar system might break up the planets into very small planetoids or pebbles to form a loose shell that would collect all the light coming from the star. The shell of planetoids would vastly increase the available "habitable" area and absorb all of the visible light. The stellar energy would be reradiated at a much lower temperature. If the visible light was totally absorbed by the planetoids a pure Dyson Sphere signature would be an infrared object with luminosity equivalent to the hidden star and a blackbody distribution with a temperature corresponding to the radius of the planetoid swarm. For the case of the Sun with the planetoids at the radius of the Earth the temperature would be approximately 300 ºK. Many of the earlier searches for Dyson Spheres have looked for so-called partial Dyson Spheres where the loose shell only partially obscures the star. The Dyson Sphere investigation at Fermilab looks for so-called pure Dyson Spheres as well as partial Dyson Spheres.

An unambiguous Dyson Sphere signature could be interesting evidence for “cosmic archaeology”, that is signs of intelligent activity elsewhere in the Universe. Cosmic archaeology signatures represent a different approach to finding intelligence elsewhere in the Universe. Unlike SETI signals generated as beacons, the creation of a Dyson Sphere signature did not require an active strategy on the part of the originating “civilization”. Lemarchand [SETIQuest, Vol. 1, #1, p.3] has reviewed a wide range of other possible signatures of extraterrestrial technological activity. An interesting distinction between SETI searches and systematic searches for objects like Dyson Spheres is that no presumption has to be made concerning the intent or motivation of the originating “civilization”. In this sense a Dyson Sphere search is more akin to a search for extra solar planets.