Possibility-if panspermia is correct (the theory that life is much older than Earth and has been seeded on many planets by meteorite impacts), then we might not expect to see other civilizations advanced enough to be visible yet. If evolving from the first life to roughly human levels takes around the current lifetime of the universe, rather than of the Earth, not observing extraterrestrial life shouldn’t be surprising! Perhaps the strongest evidence for this is that the number of codons in observed genomes over time (including as far back as the Paleozoic) increases on a fairly steady logarithmic trend, which extrapolates back to shortly after the birth of the universe.
Possibility-if panspermia is correct (the theory that life is much older than Earth and has been seeded on many planets by meteorite impacts), then we might not expect to see other civilizations advanced enough to be visible yet. If evolving from the first life to roughly human levels takes around the current lifetime of the universe, rather than of the Earth, not observing extraterrestrial life shouldn’t be surprising! Perhaps the strongest evidence for this is that the number of codons in observed genomes over time (including as far back as the Paleozoic) increases on a fairly steady logarithmic trend, which extrapolates back to shortly after the birth of the universe.