Curious how they eliminate one potential source of error
I understand that the wide physical separation eliminates local sources when they see the same signal at almost the same time in both detectors, but how do they eliminate the possibility that the vibration originated deep in the earth at a point nearly equidistant from both detectors? After all, we're talking about very, very tiny signal. Surely the earth produces its own wide range of grumbles at depths all the way down to the core. Maybe one of those just happened to look like a merging-black-holes "chirp". Probably the reason they used the word "chirp" to describe the signal is that it's a familiar pattern produced by many phenomena.
Biting the hand that feeds IT
