Beginning physics?

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Beginning physics?

Postby vivian maxine on October 27th, 2015, 2:03 pm 

It's all in the vocabulary and I know without asking that physicists stay up nights inventing new words to keep us guessing. Right? I was quite fine with "dissipative" until I opened a book and met up with dissipative structures. Do I have this right?

Dissipative structures - are they "dissipative" because of the loss of heat energy through thermodynamics in machinery and through respiration in the ecosystem of living entities? If that is right, is that the only reason they are called "dissipative"? Also, is all working machinery dissipative? Is an automobile, for example "dissipative"?

Time - someone at another thread recently suggested keeping an open mind on all theories. Absolutely correct! My open mind about time:

In the last few days, I have read - or reread these:

The past, present and future are an illusion and all predetermined. How we predetermine an illusion, I know not but it means we are not responsible for what we will do in the future.

The past and present are determined but the future is not. The future is still to come and we have control over what it becomes. Therefore we are responsible for what we will do tomorrow.

There is a past and a future but no "now". I forget the reason for that but I think I'd agree since "now" becomes the past so fast that getting a chance to do something with it for the future record requires alertness beyond measure.

All right. My questions about dissipative structures truly want answers. If anyone cares to provide them, I'd appreciate it.

My off-hand remarks about time are simply my agreement about keeping an open mind. Good idea.. Surely you would admit it gets confusing?

Then there is linear and nonlinear. Those I am "sure" I understand. If I am not nonlinear, I am dead. Therefore, best not ask.

Thank you for some illuminating comments.
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Re: Beginning physics?

Postby Dave_Oblad on October 28th, 2015, 9:31 pm 

Hi Viv,

I'm not sure "dissipative structure" has any correlation with the English word "Dissipate".
https://en.wikipedia.org/wiki/Dissipative_system

A simple analogy might be a Tight Rope Walker. This person may appear to be making many jerky movements that seem purely chaotic but in fact are required for this person to maintain balance. So the long term effect is not falling off the rope, the short term effects appear to be chaotic. Or in other words, continuous chaos may be required for long term stability in some systems.
(And I could be completely wrong.. but that's my best guess.)

The rest I am a bit more comfortable addressing.

"The past, present and future are an illusion." This comes from Causal Determination. Meaning all effects are caused by something preceding that effect. Or in other words.. the beginning of the Universe was such that here, 14+ billion years later, you would be sitting there reading this at this exact time and place. If you could rewind the whole Universe, every aspect of it, back 1000 years (say) it would still play out exactly the same.. no matter how many times you rewind it. This is pure Causality.

This idea was also called the "Block Universe". From an External point of view of our Universe, all of Time co-exists simultaneously. Past to Future, all fall on one continuous Timeline. The section of that Timeline that has your life as a segment is "All" of You personally. Each moment along that segment of You is no more or less important than the whole. That at each point on that Timeline, You will call it the "Now". But all "Now's" are equal and thus no particular "Now" is special. Thus "Now" is merely a progressive perception of the Mind and thus Time is an Illusion.

It does not detract from "Free Will" (called compatibilism). You still get to design your own future and must be responsible for your decisions. But because you can't see the absolute future and the fact you get to personally design it, then You have Free Will. The only Entity that has no Free Will would be a God. If that God knows the Absolute Future, then that God can't change it, thus a God has no Free Will. If that God could change the Future.. then that God is not "All Knowing". It can't be both ways. All Knowing and Free Will are Not compatible concepts.

Linear=Dead? Like in laid out flat...lol?

Best wishes,
Dave :^)
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Re: Beginning physics?

Postby Natural ChemE on October 29th, 2015, 2:04 am 

vivian maxine,

Human knowledge grows in people over time just as it has in our society over time. When you're just starting out, it's useful to look back at the old theories and learn those. You then progress up the ladder, 'til you reach the modern age.

It may seem like a waste, but really the good parts of old ideas - i.e. the parts we kept - are the basis for a lot of stuff. You'll definitely want to develop the mental machinery to handle that stuff before moving on.

For example: time. Time used to be just this linear concept. All frames of the universe shared the same time, and it progressed evenly. Until you're ready to move on past classical mechanics, it's probably best to continue seeing time in that sense. Afterwards, it starts getting more involved; you'll have modifications for relativity, retrocauality, differing computational timelines, etc.. None of this stuff's particularly complicated, but only if you know what it's based on.

Trying to learn concepts in advanced fields is like trying to find the bathroom in a house: really easy if you already know your way to the house, but just about impossible if you don't know where the house is at.
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Re: Beginning physics?

Postby vivian maxine on October 29th, 2015, 7:41 am 

Good sense, Natural ChemE. Trying to manipulate today without first climbing out of yesterday can be hazardous to one's mental capacity. Crawl before you walk. I agree but that can be hard if the crawling should have happened decades ago and you're having to deal with the walking of today.

Ah well. It challenges the brain and they say that is good.

Dave, I'll cogitate on what you write. What got me to that is an article in June 2015 Discover. This is about George Ellis's challenge to Einstein's contention that time is an illusion and the future is already written. He makes very good sense to me but maybe in the modern understanding, he has oversimplified. That is why I asked to hear from others. I think your post has the answer. Are you saying that what is going to happen is "known" in a way that we would never define "known"? "Que sera, sera" - What is to be will be. It's already written on a line to come.

Thank you both for replies.
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Re: Beginning physics?

Postby neuro on October 29th, 2015, 9:08 am 

Vivian,
an automobile is not a dissipative system.
Leave it alone in its garage, and it won't dissipate any energy. It will, gradually and very slowly, degrade, due to the fact that some elements are not at thermodynamic equilibrium, but it won't need any energy input to maintain its status. Neither will it be able to use any energy to restore possible degradations in its own structure. Actually, the better you preserve it from any interaction (and energy exchange) the longer and the better it will persist.

When you have it working, then you are "using" it to transfer/transform energy, and therefore - due to the second principle of thermodynamics - it will dissipate a fraction of the energy it is fed by releasing heat to the environment.

Living systems are different: leave them alone, with no interaction with the outside, and they inevitably, rapidly degrade. To remain alive they need to be fed energy (in the form of high-energy chemicals, food, or in the form of electromagnetic radiation if they are plants, capable of photosynthesis). And they need such energy to maintain their condition of far-from-equilibrium, ordered, systems. Part of the energy they are fed is used to fuel their biochemical apparatus and (possibly, e.g. animals) produce movement; necessarily, however, a part of that energy - possibly a minor part, but in any case non-zero - must be released (dissipated) into the environment, once more due the 2nd principle of thermodynamics.

Actually, this does not mean that living systems heat the Planet: animals use the energy contained in high-energy chemicals (food) by combining them with oxygen to produce the low-energy compounds water and carbon dioxide; plants use the electromagnetic energy captured from sunlight to generate and maintain their ordered organization and to produce such high-energy chemicals (e.g. glucose) from water and CO2. So, the whole alimentary chain - or the chain of life - gradually releases, step by step, the energy (heat) that it receives from the sun, which would otherwise by simply released in the environment to produce an increase in Earth temperature.

So, the concept of "dissipative system" implies that the system cannot persist, maintain (and develop) its internal organization, without gathering energy from the outside and transforming it, and therefore dissipating part of it as heat in the environment.
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Re: Beginning physics?

Postby neuro on October 29th, 2015, 9:14 am 

An interesting corollary:
increase the ratio plants to animals and you will decrease the CO2 content in the atmosphere. A lot of heat, meanwhile, will be captured in the material plants are made of.
Conversely, decrease the ratio of plants to animals and the CO2 content in the atmosphere will increase. Still, much heat might be captured in the material plants and animals are made of. Then earthquakes come about and buried deposits of organic material will turn into oil. A reserve of heat delivered by the sun to the Earth and never dissipated yet.

Now start getting out all that oil and burning it...
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Re: Beginning physics?

Postby vivian maxine on October 29th, 2015, 9:52 am 

I think I get it. I am attributing more to machinery than is correct. Yet I'm sure Capra included some kinds of machines in his description of thermodynamics. Maybe I just mis-read him. Anyway, the difference is that the structure can't just dissipate energy; it must also be "fed" energy to do so. A resting automobile is not doing that but a moving one is? We feed it gasoline and it puts out energy to move the car. We feed it oil to keep its innards functioning and therein is a fictitious "waste" as it give us no energy in return.

Oil? No oil here. Just gas off the top of the oil. :-) Now I must get dissipative by wasting energy out and about which keeps me nonlinear. :-) Thanks again for clarifications. I'll re-read when I get back.
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Re: Beginning physics?

Postby neuro on October 29th, 2015, 12:27 pm 

Vivian, the point is a car does not need to dissipate any energy, as long as it simply survives.
You and I do!

Dissipate energy means produce heat.
Any time you transfer energy from a system to another or produce any transformation of energy (from mechanical to electric, from chemical to mechanical, whatever) part of such energy will be lost (DISSIPATED) as heat released to the the environment. In principle, an ideal car would use all the energy in the fuel to move. Any REAL car, on the contrary, will dissipate some as heat when it works. However, it is not defined as a dissipative system because it does not need to dissipate any energy to exist. The difference is you instead dissipate heat even when you try to stay as still as possible, just because you are alive, and this means a lot of metabolic activity must be going on in you, therefore energy transformation, therefore heat production and dissipation.
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Re: Beginning physics?

Postby neuro on October 29th, 2015, 1:09 pm 

As regards time, I'd say that time might well be an arbitrary human invention and I am always intrigued by non conventional views, but it seems to me that there are at least two aspects of time that are far from arbitrary:
1) simultaneity - although relativity tells us that simultaneity is relative, co-presence in time is an absolute prerequisite for the existence (and for the recognition) of any pattern, and for any exchange of energy, which in my opinion are not particularly irrelevant aspects
2) delays - although the measured delays are similarly relative, our neural circuits are designed in such a way that we are very proficient in detecting (short) delays, and in producing precise delays (in generating movements).

The interesting aspect, in my opinion, is not so much that one can imagine the universe as a static 4-dimension block thrown there once and for all (a quite funereal view, Dave, with all respect :°); rather it is interesting that, thanks to our ability to introduce delays in information elaboration, we actually examine time series as sets of events (bunches of information) simultaneously present in our brain and laid down one aside of the other along an imaginary time-line which is a virtual space rather than time. And this simultaneous representation of the time sequences in our brain escapes the non existence of "now" (the simple junction between past and future), by making the "now" a portion of the spatial representation of time that extends backward and forward along the virtual time-line (in a sense, a thin slice of that 4-D block of Dave's).

Think of when you hear a sound: necessarily a sound must have a duration to be a sound (there cannot be an instantaneous vibration). Still we perceive it (the sequence of vibrations that have hit our ear) as a single, instantaneous event. And, actually, a full melodic phrase is perceived as a simultaneous unit, or, better, is perceived as a sequence, but then retained and replayed in our brain long (time!) enough to transform it into a momentary holistic perception, and an emotion.

Time may not exist. But then neither would music.
I'm not arguing; I simply prefer to think they both do exist.
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Re: Beginning physics?

Postby DragonFly on October 29th, 2015, 2:14 pm 

neuro » October 29th, 2015, 1:09 pm wrote:Still we perceive it (the sequence of vibrations that have hit our ear) as a single, instantaneous event.


Yes, and even a quick tap-tap-tap on the door.


Music

Memory’s ideas recall the last heard tone;
Sensation savors what is presently known;
Imagination anticipates coming sounds;
The delight is such that none could produce alone.
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Re: Beginning physics?

Postby vivian maxine on October 29th, 2015, 3:46 pm 

"However, it is not defined as a dissipative system because it does not need to dissipate any energy to exist. " And we do not need to feed it energy so long as we do not put it to work. Me? Imagine trying to exist without chocolate!

Thank goodness for time. If there isn't time, some very heavy explaining is in order. Imagine doing without Joshua Bell! Or 107.3 (classical radio) all day.
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Re: Beginning physics?

Postby DragonFly on October 29th, 2015, 3:59 pm 

vivian maxine » October 29th, 2015, 3:46 pm wrote:
Imagine doing without Joshua Bell!


His Angels & Demons works are beyond compare!
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Re: Beginning physics?

Postby ronjanec on October 29th, 2015, 5:39 pm 

vivian maxine » Thu Oct 29, 2015 1:46 pm wrote:"However, it is not defined as a dissipative system because it does not need to dissipate any energy to exist. " And we do not need to feed it energy so long as we do not put it to work. Me? Imagine trying to exist without chocolate!

Thank goodness for time. If there isn't time, some very heavy explaining is in order. Imagine doing without Joshua Bell! Or 107.3 (classical radio) all day.


Actually, thank goodness for man Vivian, because man actually invented "time". Time is basically nothing more than a type of measuring system man invented, and "time" exists as a singular word man uses to call and identify the different results of this measuring system(or "timekeeping" as this system is actually called)
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Re: Beginning physics?

Postby Dave_Oblad on October 29th, 2015, 9:27 pm 

Hi Viv,

Wiki wrote:A dissipative structure is characterized by the spontaneous appearance of symmetry breaking (anisotropy) and the formation of complex, sometimes chaotic, structures where interacting particles exhibit long range correlations. The term dissipative structure was coined by Russian-Belgian physical chemist Ilya Prigogine, who was awarded the Nobel Prize in Chemistry in 1977 for his pioneering work on these structures. The dissipative structures considered by Prigogine have dynamical régimes that can be regarded as thermodynamically steady states, and sometimes at least can be described by suitable extremal principles in non-equilibrium thermodynamics.

Despite neuro's definition of Dissipate, it would appear it has nothing to do with dissipating energy Per Se. Neuro is correct in regards to Entropy.. but what the articles seem to be saying is that some systems will tend to self destruct unless a bit of chaos is mixed into it that cause a stabilizing effect over time.

The papers and articles seems to imply that given an unstable system, that Chaos can have an effect of stabilizing such a system. For example in a biological system, a species that clones itself is stable for its environment. But if the environment changes too fast, then cloning stability is no longer an asset. That species may go extinct because it can't change fast enough. Given sexual reproduction, we add an element of Chaos in Gene Mixing. This Chaos allows such to modify itself fast enough to survive external changes better than simple cloning.

Or given my person on a tight rope, if he was frozen rigid, he would fall, because as a system, a slight imbalance can cause an imbalance cascade and he tips over. Rapid Chaotic adjustments can serve to stabilize such a system. So it's not so much dissipating heat.. but rather dissipating a strongly potential destructive pattern. Again.. like inbreeding in royal families. A bit of Chaos Mixing can be a good thing.

The Block Model Universe was Einsteins concept, not mine. But I like it. If you video tape a wedding for 4 hours and then hold that video in you hand, you are holding a Block Model of that Wedding. All 4 hours are in your hand in a single instant. The Block Model is just looking at the Universe from a Hypothetical outside point of view and seeing it all at once. There is nothing funeral like about that..lol. Our view from inside is a moving slice and the future hasn't happened yet from any specific temporal coordinate point of view.

The question is.. can you change the future? No.. you can't! WHY? Because you would have to know the future first... to know if you changed it. Anyway.. you are Free to write your future into being anything you want it to be (within your power). This is actual Free Will.

But from outside the Universe, whatever future you chose to write, is just a matter of recorded history when Time is seen as a whole (like that Recording of the Wedding). You may play that recording as many times as you wish and it will never change.. but you recorded everyone using their Freewill. The Bride still always say's "I DO!" at the same place in time. It was her choice.

Warning: The following is not Personal Theory. But some of it is not accepted Canon Science yet. There is much speculation in the Physics Community with regards to what Time is and isn't.. and I offer a bit of that here:

We have our Macro Time.. which we measure with a common clock. This kind of Time is not really Time.. it is strongly linked to the Speed of Light. The faster you go, the slower your clocks run. This does not mean your progress towards the Future is any different than that of a stationary object. It merely means that the dynamics of all clocks (including biological) change with Speed (or Gravity).

Then you have Real Time.. which is the progression of the Universe into the Future where everything is progressing along the Arrow of Time at the exact same rate, meaning that simultaneity probably exists Universe wide.

Then you have Quantum Time, which is still a Mystery, because it seems to have qualities of being Instantaneous Time, as observed with such things as Quantum Entanglement.

In a few years I hope the Physicists will master the Quantum and when that day arrives, we will have devices that can communicate from anyplace in the Universe to anyplace in the Universe.. instantly.. because it exploits Instantaneous Quantum Time.

When this happens, we will fully recognize Real Time, in that a Quantum Signal sent from here to everywhere and then transmitted back, will have echos all arrive back simultaneously. This will finally clear up any debate of Universal Simultaneity.

Then, when we talk to someone near a Black Hole or traveling super fast, we will be able to hold a real time conversation with them.. but.. they will sound like a sped up or slowed down voice. May take them many seconds to just say the word "Hello" as if in slow motion.. by your personal sense of clock time.

Time has many faces...lol.

Hope this has helped.

Best wishes,
Dave :^)
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Re: Beginning physics?

Postby neuro on October 30th, 2015, 4:49 am 

Dave_Oblad » October 30th, 2015, 2:27 am wrote:
Wiki wrote:A dissipative structure is characterized by the spontaneous appearance of symmetry breaking (anisotropy) and the formation of complex, sometimes chaotic, structures where interacting particles exhibit long range correlations.

Despite neuro's definition of Dissipate, it would appear it has nothing to do with dissipating energy Per Se. Neuro is correct in regards to Entropy.. but what the articles seem to be saying is that some systems will tend to self destruct unless a bit of chaos ...

The article may seem to be saying so, but it actually says "sometimes chaotic", which means it does not need to be chaotic. Although a complex system almost necessarily will be chaotic, since it will contain nonlinear relations. (please note that chaotic here refers to the mathematical definition of chaos, not the common-sense one).

As "dissipative" is regarded, I may well be wrong and Prigogine may have picked the word to mean something else, but
your same citation wrote:The dissipative structures considered by Prigogine have dynamical régimes that can be regarded as thermodynamically steady states, and sometimes at least can be described by suitable extremal principles in non-equilibrium thermodynamics.
"
Non-equilibrium thermodynamics and steady state (or "dynamic equilibrium" in biochemistry) both point to stable system conditions that are maintained through a continuous process (example a series of biochemical reactions you keep feeding reagents to and subtracting the products from).
This necessarily implies:
interaction with the outside
gathering energy from the outside
using such energy in the process
transforming part of such energy into entropy
in other words producing heat and
dissipating heat to the environment.

Dave wrote:The papers and articles seems to imply that given an unstable system, that Chaos can have an effect of stabilizing such a system.

This is not correct.
Chaos does not have any stabilizing effect. A chaotic system (complex nonlinear system) is a system characterized by basins of attractions in its mathematical description and this typically leads to reasonably stable conditions or to pathways of periodic fluctuation. But this is not "due" to Chaos (capital, as a divinity or "The Force" in StarWars). Chaos simply is a property of FULLY DETERMINISTIC complex NONLINEAR systems.
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Re: Beginning physics?

Postby Natural ChemE on October 30th, 2015, 5:40 am 

Chaos is just the opposite of the normal well-behaved stuff we look for.

For example, say you're going to go to the store. Does it really matter if you get there at exactly 5pm? If not, the situation's well-behaved; being a little early or late just has a small effect on your schedule. However, if the exact minute you get there might cause you to win the lottery, meet the President, or lose your wallet, then it's chaotic.

Chaos theory is just the study of what happens in systems where small changes in inputs (like the exact second you get to the store) severely alters results (like if you win the lottery or not).

It's neat to think about chaos theory, but it's often pretty badly over-hyped and sensationalized. The 2004 movie "The Butterfly Effect" was on this subject, but despite all its hype, apparently it wasn't very well received (I didn't see it).

Just to note it, chaotic systems don't have to be deterministic. We just usually study deterministic systems because it's really hard to analyze non-deterministic chaotic systems. Sometimes folks try though, e.g. in quantum chaos. The fundamental difference between randomness and chaos is often considered to be in the eye of the beholder: "chaotic" if you can find some method for improving your predictions based on initial conditions, "stochastic" if you can't.
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Re: Beginning physics?

Postby Dave_Oblad on October 30th, 2015, 5:34 pm 

Hi all,

As stated, I could be wrong. My initial instinct was to explain in much the same words as neuro. But that concept has been around for centuries and hardly worthy of a Noble in 1977.

Basically, it's like the woman long ago that put a Bowl of hot soup on the table.. awaiting the arrival of her husband for dinner. He got distracted at the Tavern and found when he got home.. the heat in his soup had dissipated and is now condensed in his wife ;^P

But to get a Noble, one must be able to prove something that normally would get one laughed off the stage.

Like proving a System can be long term unstable unless one introduces some Chaos that has a stabilizing effect. Ie: The man on the Tight Rope. His movements are a combination of Over-compensation and Under-compensation. There is no pattern and is thus Chaotic motion.. but it keeps him stable on the rope. (I know.. crude.. but works for me...lol)

The reproduction model seems better.. but again.. the idea is more about non-equilibrium thermodynamics.. so my analogies may be way off base (and my understanding too).

Best wishes,
Dave :^)
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Re: Beginning physics?

Postby neuro on October 30th, 2015, 6:09 pm 

I'm sorry, Dave.
there must have been a misunderstanding.

I am not negating that chaos (and nonlinearity) adds significantly to the capability of a dissipative system to persist, because (1) it can allow for a wide range of variability in its states without exceeding the boundaries of a basin of attraction (enlarge the range of homeostasis) so that it remains in the same operating mode and (2) in the face of changes in the environment that force it out of its normal basin of attraction it may well die but it may as well find itself in another basin of attraction compatible with a novel, different, stable condition (evolution).

What I'm simply stating is that this is not the reason it is called "dissipative". It is dissipative because it cannot persist without (gathering, using and) dissipating energy. Then, being dissipative, its stability may well be increased by its being chaotic. Which might not be the case for most non-dissipative systems...
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