[danso]

Maybe there's a miscommunication here; detecting underwater sound from hundreds, even thousands of kilometers away, is made possible via the publicly known laws of physics.

Detecting extraterrestrial aliens requires technology that is not publicly known. Therefore, it is not at all logical to compare "hearing an imploding submersible in the Atlantic" to "detecting aliens/UFOs"

[psychphysic]

Really you'd need advanced technology to detect aliens if Roswell was indeed an crash landing?

You've got to be kidding!