I've heard the uncertainty principle summarized thusly (and I'm sure if you amateur physicists can set me straight, I'd be much obliged): The mere fact of observing something changes that which is observed.
The good news is: the longer the universe survives, the better the chance that it will mature into a stable state. We are just beyond the crucial switching point, Mr. Krauss believed.
The bad news is: the quantum effect, a truly weird aspect of physics that says whenever we observe or measure something, we reset its clock.
So little time.
Update: Does this help?
The uncertainty principle is stated in popular culture in many ways, for example, by some stating that it is impossible to know both where an electron is and where it is going at the same time. This is roughly correct, although it fails to mention an important part of the Heisenberg principle, which is the quantitative bounds on the uncertainties. Heisenberg stated that it is impossible to determine simultaneously and with unlimited accuracy the position and momentum of a particle, but due to Planck's Constant being so small, the Uncertainty Principle was intended to apply only to the motion of atomic particles. However, culture often misinterprets this to mean that it is impossible to make a completely accurate measurement.Agh... !! So little time... !!
Update II: Oh swell! My grasp of the uncertainty principle was erroneous. What that is is the Observer Effect:
In science, the term observer effect refers to changes that the act of observing will make on the phenomenon being observed. For example, for us to "see" an electron, a photon must first interact with it, and this interaction will change the path of that electron. It is also theoretically possible for other, less direct means of measurement to affect the electron; even if the electron is simply put into a position where observing it is possible, without actual observation taking place, it will still (theoretically) alter its position.But never mind that! The Tree Falling in the Forest thingy is starting to unravel my mind-wrap!!
Perhaps the most important topic the riddle offers is the division between perception of an object and how an object really is. If the tree exists outside of perception (as common sense would dictate), then it will produce sound waves. However, these sound waves will not actually sound like anything. Sound as it is mechanically understood will occur, but sound as it is understood by sensation will not occur.Time's up! Put down your pencils!