In the Search for Extra-Terrestrial Intelligence (SETI) and life beyond our Solar System humanity has always struggled with the challenge of knowing what to look for. If life on Earth is anything to go by, we know that it requires some highly specific conditions in order to emerge, thrive and evolve.

And if the kinds of technologies humanity uses to communicate and explore the Universe are any indication, then some of this activity would be detectable, even from light-years away. Unfortunately, since we have only ourselves and our planet as examples, scientists are forced to make certain theoretical leaps in order to speculate what could be out there.

For instance, given the age of the Universe (13.8 billion years), it seems naive to suspect that some extra-terrestrial intelligences (ETIs) would not have been around a lot longer than us. It would also be foolish to assume that no other civilization would be more technologically advanced than we are.

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