US government-owned "moored passive acoustic recorder" was able to hear and record the 2023 implosion of the doomed Titan submersible—even though the recorder was 900 miles away from the dive site.

That implosion, during an attempted dive to the wreckage of the Titanic, killed five people, including Stockton Rush, the CEO of the company that built and operated the Titan.

The implosion audio was just released publicly by the US Coast Guard's Titan Marine Board of Investigation, which has been investigating the disaster in enormous detail. As part of that investigation, the Coast Guard obtained the audio from the National Oceanic and Atmospheric Administration (NOAA), part of the US Department of Commerce.

The audio isn't much to listen to—just some static followed by a staticky explosive noise that decays in swirling fashion for multiple seconds. The implosion itself, given the pressure the vehicle was under at the time, probably occurred in milliseconds, as you can learn from simulations of the event. //

Back in the 1960s, '70s, and '80s, this kind of sonic technology was deeply important to the military, which used the Sound Surveillance System (SOSUS) to track things like Soviet submarine movements. (Think of Hunt for Red October spy games here.) Using underwater beamforming and triangulation, the system could identify submarines many hundreds or even thousands of miles away. The SOSUS mission was declassified in 1991. //

"At some point, safety just is pure waste," Rush once told a journalist. Unfortunately, it can be hard to know exactly where that point is. But it is now possible to hear what it sounds like when you're on the wrong side of it—and far below the surface of the ocean.