Broadcasting but not receiving:density dependence considerations for SETI signals

摘要

This paper develops a detailed quantitative model which uses the Drake equation and anassumption of an average maximum radio broadcasting distance by an communicative civilization.Using this basis, it estimates the minimum civilization density for contact between two civilizations tobe probable in a given volume of space under certain conditions, the amount of time it would take for afirst contact, and the question of whether reciprocal contact is possible.