Here's what I sorta understand about sonic booms: The boom is caused (and I say all this tentatively) by "shock" waves (is this tantamount to air resistance caused by the plane running into the air?). And it occurs at a certain point (which can vary with temperature and air pressure). Ok, here's where I get confused: Once the plane breaks the sound "barrier" (doesnt seem like much of a barrier?), where does it go or exist in etc? Is the phenomenon of sonic booms simply the plane "outrunning" the sound it makes?