They are saying: "STOP believing the lying politicians and START believing the scientists or you're all doomed..."

Or maybe its something else....LOL!

Something like a large star and black hole coming together.

to use any form of radio for interstellar communication as it would just be to slow to be worthwhile.

But say it’s like that of the Scrambler’s in Peter Watts’ “Blindsight”, an intelligent but unconscious superorganism that operates on galactic timescales. Slow communication works for it/them because it/they is/are like a slow growing infection of adjacent star systems.

Fun stuff

have been observed to this point. These would be ones that would be noticed because they harvest a significant portion of their star's energy.

That would be my bet for our first verification of alien technological life. We haven't looked at all 300 billion or so galaxies but each one of those galaxies represents about 300 billion stars. If not a single one made it to Type III, then I think technological life must be exceedingly rare.

That and the temporal overlap required for us to be in the right place, observing the right star, at the right time to measure a civilization in that specific location is vanishingly small as well!

Say a civilization arose 4 billion years ago but was close to us, say 1 billion light years away (close by cosmic scales, lol), hit its peak 3.5 billion years ago and flamed out into extinction 3 billion years ago...the signals and "proof" of that civilization could have zipped right past the Earth while out ancestors were still eking out existence in shallow salt pools...never to be seen or received by us at all, especially if they stopped transmitting 3 billion years ago...

Humanity is on a collision course with extinction right now. We steadfastly refuse to do anything to mitigate or prevent catastrophic climate change and we show absolutely no innate ability to do so as a species. The effects won't hit everyone equally or at the same time, but by the time the assholes in power wake up and realize this, the damage will be irreversible and there will already be billions displaced, fighting for life or dead.

That may or may not happen everywhere life arises, evolves and develops technology...but on our current Venn diagram of known civilizations and suicidal/stupid civilizations, there is a 1-to-1 overlap...

If it's an already created Dyson sphere for example, we wouldn't see it, and the gravity of one star in another galaxy is not going to be noticeable from where we are.

Wouldn't we have to more or less catch them mid-sphere creation to see it?

I still wonder if we aren't one of the first civilizations. You'd need a second or third iteration of a star in an area to have all the metals and elements necessary for life. That takes billions of years. Then you need billions of years to get to highly organized life one would think.

A billion here, a billion there, pretty soon it adds up in a 13+ billion year old universe.

If its in our galaxy for example but directly across from us on the other side we might not necessarily see it.