Ask Dr. SETI ®
Could you please give me an indication of how far away we could detect a civilization with Earth-like technology? That is, if there were a society with radio, television, radar, etc., transmission power at a level equal to our own, radiating from omnidirectional antennas on an Earth-like planet, what would be the maximum distance in lightyears that we could detect these signals with our current SETI receiver sensitivity?
I would appreciate any clarification you
The Doctor Responds:
The actual range over which we can hear a signal depends upon the transmit power and antenna gain of the civilization we are trying to detect -- factors over which we have no control whatever. It is interesting, however, to speculate, and to test the results of our best guesses as to extra-terrestrial technology. The spreadsheet programs "linkanal.xls" and "ranganal.xls" allow you to evaluate your own what if scenarios. They may be downloaded from here. Using such mathematical tools as these, your guess will be as good as mine!
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this page last updated 28 December 2002
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