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I have just the book for you. -Newton's Clock: Chaos in the Solar System- by Ivars Peterson. He discusses the question of the dynamic stability of the solar system under Newton's Law of Gravitation. It turns out the deterministic nature of Newton's Laws do not preclude chaotic dynamics.

In fact one does not need an expensive telescope and a zillion dollars to see this. Get a hold of a compound pendulum with two or three rigid sections fastened end to end with a low friction pivots. Now move the pieces far enough from a straight down equilibrium position and you will see the god-damnedest gyrations and acrobatics you could imagine. The compound pendulum works strictly according to classical dynamic laws and the behavior is palpably chaotic once angular displacements of theta where sin (theta) is no longer approximately theta are given as the initial positions.

It has not, and probably cannot be shown that the solar system is long term stable (i.e. periodic). Peterson also devotes a chapter to the motions of our very own Moon. It turns out the the motions of the moon is well modeled as part of a three body problem (sun, earth, moon) and there is not good closed form solution to the motions of the moon. The moon's motions are very quirky modulo a set of boundary conditions. One of the greatest mathematicians of all time, Euler finally threw up his hands in trying to get a good closed form approximation of the Moon's motion. Fortunately we have powerful computers now and we can generate numerical approximations with resolution well within observation error so we get rather good short term predictions of the moon's motion (say of the order of ten thousand years). But this is still not proof that the earth, sun, moon is a dynamically stable system where the phase space can be finitely bounded.

ruveyn

I never claimed the infinite stability of anything. Nevertheless there is negative feedback for the limits within which we live to preserve a reasonable stability. We all die but nevertheless have a modicum of stability during most of our lifetime which is acceptably dependable. Many living interactive systems exist in that temporary stability and it is that stability which is sensitive to gross depredation by human activity.

No we dont. Its just that our minds are shaped to look for patterns and consistency which is why our senses so often deceive ourselves. Our memories are revisionist as well.

A good book dealing with this is "the drunkards walk" by by Leonard Mlodinow. Its a fun light read and deals with chance, perception and observer bias.

My favourite part in this book was on how one researcher came to understand that positive and negative reinforcement play no appreciable role in future performance.

I recommend it. Mlodinow is a knowledgeable man. http://www.amazon.ca/Drunkards-Walk-Ran ... 0375424040

"...the whole science of cybernetics evolved out of self aiming guns ..."

Some people can be so silly when they state things in this manner, "It just evolved out of...." Woooooooooooooooooooooooooo, things happening on their own,... right. But then you also gave credit to the designer involved also, "through Norbert Wiener's work...." and such is actually a credit to you. It just evolved, ...by means of an engineer....

All you have done is confirm that balanced natural systems have their tipping point.

Newtons indication of action and reaction shows this at a fundamental level.

Organisms function homeostatically in order to exist. Yes, they are temporary over a long time period but within that period they maintain stability. That's undeniable.

I have just the book for you. -Newton's Clock: Chaos in the Solar System- by Ivars Peterson. He discusses the question of the dynamic stability of the solar system under Newton's Law of Gravitation. It turns out the deterministic nature of Newton's Laws do not preclude chaotic dynamics.

It has not, and probably cannot be shown that the solar system is long term stable (i.e. periodic).

No, these systems have nothing that inherently makes them "balanced." If you model them, you do not, in general, find stable fixed points, or even limit cycles.


Somebody didn't pay attention in high school physics, it seems. You've made this comment a couple times before in this thread, and I think you should know that you are badly misinterpreting Newton's Third Law.


Homeostasis is not equilibrium or stability. Homeostasis is an active attempt to stay away from equilibrium, because equilibrium is death.

To say that the mammalian body does not maintain an equilibrium of body temperature, chemical balances to see to it that dynamic processes continue in a functional fashion, etc. is to ignore the most basic life processes. It is a dynamic equilibrium, not a static one but equilibrium nevertheless.

No Sand, you really just don't seem to know what these words mean at all. At the moment, my body is at a temperature of approximately 37º, while my environment is around 19º. That is not equilibrium—at equilibrium I would be the same temperature as my surroundings. Homeostasis is the process by which my body tries to avoid ever reaching equilibrium. If my body were at 19º, I would die. Millions of neurons in my brain pump sodium and potassium against the concentration gradient to allow me to think. With those cells at equilibrium, I would be in a coma. A living cell is one that keeps away from equilibrium. This is even how it is defined in Campbell/Reece, the standard undergraduate text in general biology. Equilibrium is death for a cell.

I begin to think it is not worth the hassle of debating this with someone who is obviously scientifically illiterate.

I begin to think it is not worth the hassle of debating this with someone who is obviously scientifically illiterate.

This is the definition of equilibrium from the web:

A system in dynamic equilibrium is a particular example of a system in a steady state. In a steady state the rate of inputs is equal to the rate of outputs so that the composition of the system is unchanging in time.

This is the situation of homeostasis I have been referring to in that life maintains a steady state of internal temperature and a dynamic balance of energy gain and loss. Even the steady state of normal growth and decay is a balance of sorts but that requires a flexibility of concept you may not be willing to concede. If you find this unscientific we will, I suppose have to investigate what we each conceive of as science if you want to bother. I'd rather not.

What is "destroying [nature]?" Matter and energy can be neither created nor destroyed, only shuffled about.

Feedback systems in a changing environment do not converge to a fixed point in the phase space of the system. They keep the state of the system in a region of operability. For example, the furnace thermostat system. Since one's house is always loosing heat to the outside, the system will keep the inside temperature in an interval between the lower set point and the upper set point. The inside temperature oscillates between the lower value and the higher value. It does not simply go to a temperature and stay there.


Living organisms have negative feedback that interacts with the environment to keep the state of the organism in a "safe" region of the state-space. To be alive is to be far from thermodynamic equilibrium. Dead critters are in thermodynamic equilibrium with their environments. Live critters are not. The state of a living organism varies over time and does not converge to a fixed state while the organism is alive.

ruveyn

As the definition indicates, a steady state does not necessarily include the surrounding environment. By your take equilibrium is a fantasy since the entire universe is subjected to the the second law.