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Methods dealing with how to contact other planets that are supposed to be inhabited by “intelligent” civilizations have begun more than one century and a half ago. The historical question has been already treated in several studies and the aim of this paper is not to provide details on that aspect. On the other hand, it could be interesting to make a comparison between the different approaches to...
The present overview covers the period from 1820 to the beginning of the 20th century. Emphasis is laid on the latter half of the 19th century because many efforts have been done at that time to elaborate schemes for contacting our neighboring planets by interplanetary telegraphy. This period knew many advances not only in planetary studies but also in the nascent field of telecommunications. Such...
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