Thirty years ago, astronomer Carl Sagan convinced NASA to turn a passing space probe’s instruments on Earth to look for life — with results that still reverberate today.
The fact that most of our signals for extra-terrestrial life are based on life on earth has always made me concerned we'd miss something. This has made me reconsider a little. We would miss life unlike earth's with our approach, but without an analogy like this to draw on, how could we know?