Today is a good day to die.
I didn't say for whom.
If there are alien civilizations, my guess would be they’d have faster than light comms to talk across interstellar distances on some kind of real time basis. Meaning not RF based so we’d have no way to capture them till we have that tech as well. They could be all around us and we’d never know it.
Quantum based.
“They could be all around us and we’d never know it.”
BINGO! Imagine that recently discovered primitive tribe in South America. A team of Navy Seals could surround them and communicate freely with each other and the natives would never be the wiser for it. Their technology is too primitive to identify the technology of a SEAL team. In a like vein, why and how, are we to suppose that we can detect transmissions of vastly superior extra terrestial technology? They could very well be all around us and not want to be detected. If they want us to know they are out there, they can stoop to our level and bang messages out on hollow logs with long sticks.