Dyson sphere
SETI has adopted these assumptions in their search, looking for such "infrared heavy" spectra from solar analogs. Fermilab has an ongoing survey for such spectra by analyzing data from the Infrared Astronomical Satellite (IRAS). Identifying one of the many infrared 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.