Is there any simple way of explaining why our model would break down at that point? The first (utterly naive) guess that springs to my mind would be that at th

Is there any simple way of explaining why our model would break down at that point? The first (utterly naive) guess that springs to my mind would be that at that point the vibration would be sufficiently fast that when sampled at a Planck time interval, there'd be no motion at all. Like overflow of an unsigned int. This is almost surely wrong. :)