Oh? Is there a particular theory you appreciate?.... i saw a few (from my own google search )
Optic nerve impulses "bleed over" into the part of the brain that processes sound. The immediate environment has to be extremely quiet, which it was. Nobody was with me, and there was no traffic noise.
"I absorb energy like a sponge everywhere I go. It allows me to see the world and my purpose in it." Zak Bagans, Ghost Adventures (INFJ)