> My 2c is extra-terrestrial civ is less likely than co-terrestrial civ (subterrainean/ocean) - but lets stop talking about this like they are hallucinations or possible atmospheric phenomenon.
Why?
This whole thing reminds me a bit of the "Havana Syndrome", in that:
- It's an extraordinary claim, presented with limited evidence.
- It defies obvious logical explanation (i.e., a motive).
- The phenomenon lacks a clear definition, leaving the door open for multiple disparate phenomena with different causes to be lumped together.
I believe the third aspect is really underemphasized as a causal factor in "hard to explain" phenomena: because this may in fact be multiple different phenomena, with different causes, it's likely that any single mundane explanation does not explain all observations, and thus appears to be a weaker explanation than it is.
This is sort of a "defender's dilemma" of strange phenomena: if you can't explain all of them, you appear to be unable to explain them. But because of the aforementioned definitional problem, that's not necessarily a surprising or meaningful thing.
To your specific point: the idea of a co-terrestrial civilization is extraordinary. I struggle to imagine the only evidence would be a few spurious radar signatures and odd videos.