Let’s start by clearing something up. Whatever the ins and outs of the search for extraterrestrial intelligence over the years (that I’ll label as SETI) the bottom line is that we have not yet done enough to tell whether the cosmos is devoid of communicative species or crammed with them. Nowhere has this been articulated better than in the work by Jason Wright, Shubham Kanodia, and Emily Lubar of Penn State and their ‘Haystack equation’. This shows, unequivocally, that to date we’ve searched about as much as if we’d stared into a modest hot-tub’s worth of water from all of Earth’s oceans.
Consequently, to say that ‘there’s clearly nothing out there’ is like looking in that hot tub, not finding a dolphin, and concluding that dolphins therefore do not exist anywhere on the planet.
Given that fact, I think it’s perfectly reasonable to examine how communications across interstellar space might play out, should they exist. This does, of course, require a whole bunch of prior assumptions.
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