The Search for ExtraTerrestrial Intelligence continues to look at and listen to stars for evidence of other civilizations. Another target has been identified, probes, particularly probes that could have arrived in our solar system and that are either dormant or observing us. It is a logical possibility for civilizations that are advanced, curious, and patient enough to study their local stars. SETI looks for transmissions that are either actively aimed at us, or merely radiate with enough energy for us to detect. A more active civilization could launch probes to neighboring systems just like we do to neighboring planets. In their case, however, it would make sense for them to search for more than the microbes we hope to find with our probes. It would be logical for them to also search for technological signals. Considering the size and age of the universe, and the relative density of our part of the galaxy, it is feasible and reasonably likely that we may find a probe before we detect an interstellar signal. If we see such a probe directly or detect its signal, the response time for dealing with an extraterrestrial civilization dramatically shrinks because in some way they are already here. Maybe.
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