Michael el Chayil

The laws of physics (classical, anyway) are expressed mathematically as second order differential equations. Besides that cool fact, here is another: If you would know all the laws of physics and two more bits of information, then you could (in principle) deduce the entire trajectory/history/travels of an object. Those two bits of information are either: The position and trajectory of the object at the beginning of it's travels (aka Cauchy or initial conditions). The position at both the beginning and end of the trajectory of the object (aka Dirichlet or boundary conditions). (Sigh... the physicist in me needs to qualify that any point(s) along the trajectory will do, because the laws of physics are time reversal and translation invariant. I would note sources for the interested reader, but I am quite confident that the only interested reader at this point is yours truly.) None of that, of course, has anything to do with Sefer Tehilim. The idea, though, is quite relevant to Dovid