I dislike this argument. We know that fish exist, and we know they live in water, and we know the ocean is a large body of water. We also know that searching for fish in any body of water with an 8 oz water glass is pretty silly, because we understand that fish avoid predators.
We don’t even know that there’s any life out there, intelligent or not. There’s evidence about organic molecules, so that’s a good start. But looking for intelligent life and then explaining why you haven’t found it sounds like rationalizing to me. I haven’t found any three-headed unicorns yet, either, and I’ve been looking under a lot of rocks with my butterfly net. Have I looked under every rock? No. So I still have a lot of looking to do…
I see the main reason that we haven’t heard from other civilizations as being that they have no reason to send signals strong enough to reach us. Let’s consider our efforts to transmit signals strong enough for other civilizations to detect…
The SETI program started around the time that megawatt TV transmitters were a new thing. Sixty years later, we have managed to make our TV transmissions modulated to the point of looking like white noise, and most folks dodn’t even receive signals from the big transmitters, so it’s a matter of not much more time before they’re turned off.
As far as intentional transmission of SETI signals, I have observed that our civilization seems to have less and less patience for funding pure science, so the chances of a planetary-scale transmitter being developed and turned on are pretty slim. And where would we aim it?
Don’t even get me started on interstellar travel. E=mc^2.
What really worries me is that there may be hundreds of civilizations that can pick up all the noise we’re making, and all those civilizations are saying, “Shut up! Shut up! THEY will hear you!”
Space is big. You just won’t believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space. --Douglas Adams
The corollary to that is that space is really long. We’ve been transmitting in a way that can be remotely sensed for ~60 years, and as you say we’ll probably transition to more efficient transmission media (like fully wired , directional antennae) within the next 40 odd years. So there will be a chunk of transmissions spreading through the universe from earth that is roughly 100 years ‘deep’ If no one is listening for the 100 years while that chunk is passing their planet, then we won’t be heard. Vice versa, if some other planet’s 100 year chunk passed Earth anytime before 1960, then we’ll never hear them either.
over the past 10 years, more or less, humanity has run an experiment which demonstrates not only the lack of extraterrestrial visitors but also the absence of such lifeforms as sasquatch. consider, over the past 10 years approaching 99.99% of humanity carries a video and still cameras with them everywhere they go and yet verifiable images of such organisms are notable by their absence. our reliance on mobile technology has demonstrated that such as those do not exist.
Unfortunately it doesn’t One Box, but this XKCD What If? basically covers the challenges alien astronomers face it trying to detect us by known means. The end is grimly funny.
Life, on the otherhand, should be relatively easy to spot: Oxygen is unlikely to exist anywhere in it’s elemental form that doesn’t have life. O2 is so vigorously reactive, that the only way for it to exist in an environment is through something like photosynthesis, which is life. So, basically, when we look out at the universe anywhere with peaks at the relevant frequencies for O2 is probably harbouring life. Or, at least it was, several million years ago when that light left the planet …
