Sort:  

Well, yes -- that's what I'd always been told. So what is the sound?

It's actually the sound of the radio waves emitted from radiation. NYT has a pretty good write up on the matter. https://mobile.nytimes.com/2017/05/03/science/nasa-cassini-sound-recording-saturn.html

Sound is energy passing through a medium ( air, water, etc.) Because there is no medium in space , only vacuum, sound can't travel. But there are plenty of other energies running through space, so it's no surprise the rings emmit waves.

Or is there? Looks like a case of if a tree falls in a forest and no one is around to hear it, does it make a sound?

Sound doesn't travel in a vacuum, and space is a vacuum.

That's correct, and rockets cannot propel in a space/vacuum, either. But I digress.