Individually doing atmospheric analysis for every planet in the galaxy is probably an impossible task for a civilisation confined to a single solar system. Listening for signals is something our civilisation already does. If we discover radio signals from a primitive civilisation in the next star system over there’s a non-zero chance we’d panic and try to wipe them out.
That’s the risk that dark forest theory is talking about. Maybe the threat comes from a civilisation dedicated to wiping out intelligent life that just hasn’t found you yet, maybe it just comes from your nearest neighbor. Maybe there’s no threat at all. The risk of interplanetary war is still too great to turn on a light in the forest and risk a bullet from the dark.
And while knowing this, why do we still not choose to just observe and be as quiet/ non existant as possible?
The big thing people over look when considering the we are broadcasting thousands od watts into space, they might hear use is SNR
Signal to noise ratio. (the more random stuff on a frequency the harder it is to read the signal)
Yes, humans are pumping out a huge amount of radio (etc) signals into space. it is not coherent or directed.
Thousands of antennae all over the world pumping different signals but from far away, they are all noise interfering with each other.
IIRC: Even if there was a radio telescope only a few light years away, all they would see pointing directly at earth would be static.
Not to mention the signal degrades, and the signals from the ww2 era have only reached 80 light years away. Any farther away and the signal has not reached them yet
Even then, the signal strength is not high enough. It gets overshadowed by the CMBR before it gets anywhere significant.
Had to come to the bottom of the thread to find the only take that matters. Talk of our signals being noticed is about unthinkable given the inverse square law.