the trouble is, you may only hear it if you re literally on top of it. it s not something that resinates across the entire ocean and it depends on the thermal layers, how cold it is in the ocean, what temperature layers you have in the ocean, that can all inhibit the area of sonar, the hydrophones being dragged by ships, to pick up the sonar ping. in this area, the depth is another huge factor. we re talking about two to three miles deep. interestingly, though, while there s a mountain range in this area underneath the water, the conditions in the atlantic ocean where air france 447 went down, that was described like the rocky mountains, this is more like the appalachian mountains, more of a rolling hills, rolling mountain kind of scenario under the water, but still, very difficult terrain, very deep to find this wreckage, if they are able to spot the debris, then backtrack, calculate where it came from and how far it may have drifted in the ocean. back to you. so, tom, as we look at