PASSIVE AND ACTIVE SETI STRATEGIES USING THE SYNCHRONIZATION OF SN1987A

A passive and active strategy for the reception and transmission of ca ll signals, from and to other possible extraterrestrial civilizations is suggested using the explosion of SN1987A. The reception area is an ellipsoid with the Earth and the supernova in its focuses, in the dire ction of SN1987A. Three hundred and forty objects have been identified inside this surface and four of them are stars with environments simi lar to our sun (e.g. necessary for the development of life and intelli gence). A search strategy to look for ''fake'' pulsars signals, origin ated in other possible technological civilizations, in this direction, is examined. The active strategy consist in the transmission of terre strial signals towards the hyperboloid surface (with the same focuses) in the antipodal direction of the supernova explosion. Thirty-three o bjects have been identified inside the hyperboloid and three of them a re solar-type nearby stars. The transmission characteristics of a terr estrial origin ''fake'' pulsar (e.g. modulation, frequency, bandwidth, periods, duty cycle, etc.) are discussed in some detail. The possible use of available planetary radars to develop such proposal and the cr iterion of artificiality, without any implicit code or semantics is re viewed. A difference between active search and communication is establ ished.