[Bill S (OP)]

Maybe I got no response because the correct word was 'increase' instead of 'decrease'.

I meant to query this but lack of time, and an influx of responses deflected me.   

#2 should now read: “How can entropy increase on a universal scale, while having structures (atoms, planets, stars, galaxies, plants, life forms, etc) being formed by organizing entities (gravitational, chemical, nuclear,  DNA, etc)?”

Possibly the answer is that entropy can, and does, decrease locally; but the mechanisms of such decreases give rise to globally increased entropy.

These days entropy is firmly linked to atomic theory and statistical physics, but engineers were using the concept before the scientific establishment in general believed that atoms were more significant than any other Greek “mythology”.

Shuffle a deck of cards out of the pack. The cards have an order, it's just not the one matching the standard definition.

Precisely, their order makes no difference to their thermodynamic entropy, but global entropy is decreased by the action of shuffling.

Let's move ahead with a set of atoms at approx. 0 Kelvin. Near zero energy, but having a fixed arrangement, highly ordered.

I would see this as a “system” that (locally) has very low entropy.  Presumably, you were thinking in terms of a process by which the temperature of this “set of atoms” was reduced to “near zero energy”.  This process must lead to globally increased entropy.

[yor_on]

Phyti " A deterministic universe is not possible, since it would require a simultaneous knowledge of its current 'now' state. "

Well, you can. Just allow all possibilities statically.  Forget 'time' for it. Then allow for a arrow and decoherence, scaling it up. Also allow for HUP and 'free will'. Now you got both, your local arrow combined with your free will, redefining your reality in a dynamic manner. 'It's not 'deterministic' in a usual sense, although you can see it as all 'states possible' already are 'known'. The beauty of it is that I don't need to introduce 'new universes' for each 'probability possible', I do it the opposite way, letting your free will create reality, with the rest being 'probabilities' unfulfilled.

You could possibly see it as a result of so called 'super positions'. If one assume that 'systems' unobserved are in superpositions then those include all possibilities too. the definition of a outcome is another thing, but as long as those superpositions exist the system is open for interpretations, no matter what the question or/and circumstances might be. With the probability of a outcome defined by the circumstances surrounding 'the experiment/question' etc.

[jeffreyH]

In the universe we have families of galaxy types. These include elliptical and spiral galaxies. On this scale we see order. That is irrelevant. There is disorder in the detail. In other solar systems we are finding planets that continue to defy expectation. There is a greater variety than expected. So entropy may really be a localised phenomena which is hidden from view on a global, universal scale. Much as the quantum world is hidden from our macroscopic view. The devil really is in the detail.

[evan_au]

galaxy types... These include elliptical and spiral galaxies.

Spiral galaxies have a somewhat orderly motion within the galactic disk - and somewhat less orderly in the central bulge.
- This is because, over time, stars which have high velocity or orbit well outside the galactic plane (eg captured dwarf galaxies) have their motions averaged out. This averaging of angular momentum means that more mass ends up in the galactic bulge (and ultimately, in the central black hole).

Elliptical galaxies have much less order in the motion of their stars (higher entropy)
- Some astronomers have suggested that elliptical galaxies could form from the recent merger of two large spiral galaxies ("recent" in astronomical terms)
- This would throw the two orderly motions into chaotic motion
- It is only with time that the random motions of the individual stars average out
- Some stars will plunge close to the new galactic core (and perhaps feed the new, merged galactic black holes)
- Others will be thrown out of the galaxy entirely (where is it hard to see them)

Such a merger is on the horizon for our Milky Way galaxy, and the larger Andromeda galaxy, in about 5 billion years.

This chaotic stage during the merger makes it hard to time-reverse a galaxy merger as a thought experiment
- If you could measure the position, velocity and mass of all the stars of a merged galaxy (perhaps not possible if they have been swallowed by the central black hole, and not easy otherwise)
- And try running time backwards in a simulation
- I doubt that you will end up with two neat spirals!

[Bill S (OP)]

Just allow all possibilities statically.  Forget 'time' for it. Then allow for a arrow and decoherence, scaling it up. Also allow for HUP and 'free will'. Now you got both, your local arrow combined with your free will, redefining your reality in a dynamic manner. 'It's not 'deterministic' in a usual sense, although you can see it as all 'states possible' already are 'known'. The beauty of it is that I don't need to introduce 'new universes' for each 'probability possible', I do it the opposite way, letting your free will create reality, with the rest being 'probabilities' unfulfilled.

Doesn't this result in a reality that exists only in the mind?  Dorothy Rowe  maintains that reality for each of us is the sum total of our brain’s interpretations of the flood of external stimuli it constantly receives, but she's a psychologist.  Should we be looking for some objective reality?   

 

[guest4091]

Bill S #20;

I would see this as a “system” that (locally) has very low entropy.  Presumably, you were thinking in terms of a process by which the temperature of this “set of atoms” was reduced to “near zero energy”.  This process must lead to globally increased entropy.

---

This example was intended to remove any association of entropy with order. Clausius (1800's) is credited with the 2nd law of thermodynamics which defines entropy as 'a measure of available energy'. It applies to all forms of energy.

A star is formed from gravitation acting on a cloud of dust/gas. Isn't this a case of a  diffuse low entropy object transforming to a high entropy object?

A seed is planted. In the presence of water and sunlight from the previous concentrated source, genetic code instructs the seed to form a structure, which when harvested, serves as an energy source for a life form.

This shows entropy simultaneously changing in both directions, globally and locally.

For a finite universe to 'run down', would require removal of the known forces of physics, which are organizing matter into concentrated systems of energy.

[guest4091]

yor_on #21;

There are two things of interest.

1. What is the state of a system.

2. Do we know the state of a system.

Probabilities are weighted values from analysis of statistics (which are historical).

They are used for predictions, when causes are unknown (eg. particle physics) or too complex to calculate (eg. weather).

They are useful (eg. astronomical observations) only because the laws regulating the behavior of the universe are consistent.

--------

Knowing the state of a system requires observation. If you are observing an object 100 ly distant, your knowledge of its state is outdated. You don't even know if it's still in existence. (The tourist pulls over to ask for directions. The old man replies: 'it's down the road, where the old school house used to be.')

Because light speed is finite, the age of your data depends on distance.

If you flip a coin, in the air it can be considered a superposition of HT. It doesn't have a definite state until it lands, is observed.

[guest4091]

Bill S #24;

Doesn't this result in a reality that exists only in the mind?

---
Relativity has shown perception is reality confined to the mind.

[Bill S (OP)]

However, there are many examples of open systems with increasing entropy (like the cup of coffee on my desk into which the added cream is dispersing).

I’ve just noticed this, and find myself wondering about it.

Your cup of coffee constitutes an open system.  Heating it increased its entropy.  What happens to the entropy of this system when you add cream?

The temperature of the cream is raised, so its entropy increases, but this lowers the temperature of the coffee, decreasing its entropy.  Thus, the entropy of the “system” decreases.  (?)

[Bill S (OP)]

I guess that coffee is really cold by now.   I still see its entropy as decreasing, although the process of heating and cooling will have increased global entropy.  Comments?

[Halc]

Your cup of coffee constitutes an open system.  Heating it increased its entropy. 

The hot coffee is capable of doing more work than was the cold coffee, therefore it seems that heating it reduced its entropy.
I know you've been defining entropy as disorder, but I don't know a way to quantize that.

[yor_on]

Yep Chiral, it has to be that way

" However, it also seems almost self-evident (*warning bells*) that the early universe must have been more ordered than it is now. "

the other direction would , actually, be pretty interesting :)

Damn.

why do you do this?
Make me think?

[Bill S (OP)]

The hot coffee is capable of doing more work than was the cold coffee, therefore it seems that heating it reduced its entropy.
I know you've been defining entropy as disorder, but I don't know a way to quantize that.

There was some “devil’s advocate” type posting in this thread, because I was trying to sort out my thoughts about the appropriateness, or otherwise, of equating entropy with order.

My current position is that I think the analogy, like analogies in general, fits where it touches.  Trying to extrapolate it beyond its useful limit serves only to obnubilate the issue

[Bill S (OP)]

Doesn't this result in a reality that exists only in the mind?

Relativity has shown perception is reality confined to the mind.

I think it’s important to distinguish between perception that is confined to the mind, and reality that exists only in the mind.  The latter is a dubious path to follow.

[evan_au]

how ... does vacuum thin interstellar gas and dust come together to form planets?

See: https://en.wikipedia.org/wiki/Protoplanetary_disk

[CPT ArkAngel]

From a cosmological perspective, the principle which says entropy always increases is just a belief, because it could only be a phase. The universe being in expansion implies that the quantity of information always increases as the total volume or surface, depending on which theory you are referring to. If there is a limit to the quantity of information, this means entropy cannot increase forever...