Free Astronomy Magazine November-December 2015

ASTROBIOLOGY 42 In the constellation Cygnus there is an ap- parently normal star that over a period of a couple of years has shown two inexplicable dips in brightness. No known natural phe- nomenon seems to be at the origin of this abnormal behaviour and there is someone who does not exclude that the cause should be found around the star in the form of megastructures built by an alien civilization. Discovered Dyson sphe NOVEMBER-DECEMBER 2015 by Michele Ferrara T aking up an idea first postulated in 1937 by the science fiction writer Olaf Stapledon, in the early ‘60s Free- man Dyson, renowned physicist and math- ematician, theorized that an advanced civilization, increasingly in need of energy supplies, could harness the radiation of its star by building all around it, at a safe dis- tance, a megastructure capable of collect- ing stellar energy to be then made avail- able to the same civilization. Although Dyson initially spoke of “shells”, such uto- pia has gone down in history as the “Dyson sphere” and has so far been hosted