The Fermi paradox revisited: Technosignatures and the contact era

Bold and odd. I read Under the Skin. Excellent and innovative sci fi, but nobody goes that far and spends that much even for a Kobe beef burger. Even here on bloody barbaric Earth, weapons exist mainly to keep trade from being disrupted and the largest military has an environmental compliance department.

Before we worry about communicating with civilization far away in space but coexisting with us in time, we should work at communicating with civilizations coexisting with us in space but far away in time.

One of my favorite "out there" theories is that it's possible (and I mean conspiracy theory possible) that the Paleocene–Eocene Thermal Maximum[0] was caused by an industrial civilization facing the same global warming problem we are today right here on Earth, wiping itself and several other species at the time out, but otherwise leaving the planet fine and recovering in short geological time.

The interesting part of this "theory" is that because PETM happened 50 million years ago, even if there was a civilization as complex and large as ours today, very little (essential none) evidence of it would survive.

My last bit of techno optimism is that if we do find ourselves unquestionably headed towards climate catastrophe, we should start investing research into figuring out how we might send some kind of message to a future civilization that emerges 50-100 million years after us. Something along the lines of "human were here! watch out for those hydro carbons!"

0. https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Therm...

Until SETI locates something like a pulsar braking and accelerating to signal prime numbers we're really really really unlikely to stumble onto more life. Space is just too big.

What's hard to comprehend is how there could be a possible way to preserve our consciousness through a hibernation state. Like, our cells might not die, and we might be technically revived, but we'd still be brain-dead.

And if we figure it out, does the original "experiencer of consciousness" in that body return to life? Or is it a new consciousness, with the same memories, but the original person who went to sleep would never experience waking up again? And how would we be able to test that?

If we asked the "new experiencer of consciousness" if they are the original, they would say yes, as they'd have all the same memories as the experiencer who initially went under. Kind of like the color blind problem, but much harder to objectively test, if not impossible.

Consciousness, behind a unified theory of everything, is one thing I hope is answered in my life time. Probably won't be. But it's such a mystery.

An old NTSC video signal has a clear periodic structure. Simply counting lines is going to reveal a lot about the structure and if anyone gets the idea of plotting lines they will figure out how to decode it.

An efficient digital signal is going to maximize the use of bandwidth if it looks like white noise. That said, a signal like that needs a carefully calibrated receiver, so part of the signal in time-frequency space is going to be allocated for something that is easy to acquire and will tell to how to decode the main signal. You might see a periodic structure: if you want to run a "signal frequency network" with multiple transmitters with the same signal, have to deal with a lot of reflected signals, or listen from a mobile terminal that suffers from the Doppler Effect you will probably turn off the signal for part of the cycle so that reflections can die down and you can reset your echo cancellation algorithms.

Thus digital signals aren't going to be invisible but they are going to spend maybe 5% of the energy in a way that is easy to interpret as opposed to all of it.