More Heat from the Arrow of Time

Continuing the theme of "Heat" and "Energy" led to a startling conclusion.

So we have three laws of Thermodynamics. All sorts of concepts have sprung out of this field, such as "Statistical Mechanics", "Carnot Cyles", "Heat Efficiency", and "Ideal Heat Enchangers".

However, the most infulential was the concept of "Entropy".

Simply put, Entropy is the measure of how disorderly a system is. The more disorderly, the more entropy. For example, a teacup falls to the floor and smashes. It falls apart but gains a lot more entropy because it is far more disoredered after the smash.

More accurately, we say "system" has gained entropy, the "system" being the cup PLUS the floor.

All this is intricately connected with thermodynamics, and is one of the central tenets of the field. Recall the three Laws of thermodynamics, cynics' version:

Law 1: "You cannot make a profit, only break even"
Law 2: "You can only break even if banking is free"
Law 3; "The bank is always closed"

Taken all together , they simply state that "you can never break even". the translation of this into real physics means that, in any process whatsoever, ANY process, there will always be heat loss, and that no "system" is 100% efficient.

Thought of this way, it actually means that a perpetual motion motion machine is not only impossible, it is forbidden even in principle.

However, this ia a digression to say the least, if not less.

The whole entropy thing hangs completely on the second law, which can be "translated" into yet another statement:

"The change in entropy in any system is always greater than zero"

In scientific parlance,

" dS > 0 "

where "S" is entropy and the little "d" is the universal scientific symbol for "change".

Bear this in mind, because it has as a far deeper significance than at first meets the eye.

For now, though, consider physics in general. All physics is governed by laws, and those laws are expressed through mathematical formulae. Formulae are made up of letters, symbols and numbers, and usually some are quite familiar. "x", for instance, can be a number representing a distance, a volume, etc. Capital "t", or T, is usually "Temperature" and capital "p", or P is usually Pressure. "q" is usually electric charge, and E usually Electric field (sometimes it is Energy, too).

A lot of these "variables have "direction", too. For instance going North is the opposite of going South, so we call them "x" and "-x" (it does not matter which). We all know that electric charge is either positive of negative, so we write "q" or "-q" depending on whether the charge is positive or negative.

However, we can't write "T and "-T" simply because the equations won't allow it (yes, I know you can have negative temperature in life, such as liquid nitrogen boils at -196 deg C, but that is a consequence of the arbitrary scale, namely the Celsius scale).In the physics world, all temperatures start at absolute zero so it does not make any sense to have a negative temperature. More easy to understand is pressure - you most definitely cannot have a negative pressure.

The point is this: The equations sometimes don't care if the thing has a positive or negative sign. When you plug in the values and turn the handle, the answers always come out the same even if some things have a minus sign in front of them. Time, "t" is one of them. That is, the equations don't care if you put a "-t" instead of every "t" because the answers are always the same.

You can run the equations backwards in time and the numbers don't care!

Time has no "arrow"!

Here's the rub: The second law of thermodynamics contradicts this!

For example, take the smashed cup. No way in the Universe do you ever see the cup reassemble itself and jump back into your hand, do you, complete with anti-smashing sound?!

Time DOES have an "arrow"!

Which is correct? They can't BOTH be right!