NASA has released an eerie audio clip of sound waves emanating from a supermassive black hole in the Perseus galaxy cluster, ...

This initial acoustic wave affects the second and third light-sound processing step with the ... serve as an information propagation medium. Image can only be used in context of this publication.

We can't hear these sound waves, but when they reflect off different parts of the body, they create echoes that are picked up by the probe and turned into an image called an ultrasound scan.