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How old is the universe?

Started by zorkan, January 21, 2024, 01:45:28 PM

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zorkan

I was talking about the 2nd law and not the 1st law of thermodynamics.

Asmodean

#31
Yes... And an open system is one that has its inputs and/or outputs of energy. A closed system does not.

That applies regardless of the number you put in front of the law.

A human is wholly dependent on both inputs and outputs to stay human. The universe may or may not on the largest of scales. Most everyday practical (as opposed to theoretical/mathematical) systems are indeed open.

EDIT: Ok, for clarity, this is the second law of thermodynamics.

A cyclic transformation whose only final result is to transform heat extracted from a source which is at the same temperature throughout into work is impossible.

There are conditions, chief among them that it takes place in an isolated - or closed dynamic system, which can be achieved mathematically or by increasing or decreasing its scale of definition until reaching a state where the system does not interact (through heat and work, if you would follow the definition precisely - means exchange energy, more broadly speaking) outside itself.

In a closed system, entropy always increases. This can be explained by statistics - for every ordered state of a dynamic system, there are infinite less-ordered states. Looking back at the definition, it means that a system is far - far to the pover of far more likely to keep cooling if left to its own devices than it is to heat up. (Though local variations are possible. Within that system, there can be pockets where entropy decreases, even though the overall system does the opposite) An open system can be "trivially" heated up by adding energy. The aforedescribed pockets could be examples of such systems - or subsystems, as it were in this case.

Whether it be first law or second or third - they all concern thermo[heat/energy]dynamics[motion/exchange/forces]. Be it conservation of energy or the increase of entropy, we are still operating within the same constraints.

I hope this clarifies matters.
Quote from: Ecurb Noselrub on July 25, 2013, 08:18:52 PM
In Asmo's grey lump,
wrath and dark clouds gather force.
Luxembourg trembles.

Asmodean

[Upon re-read]

I do wish I could draw stuff with symbols and graphs and visual aids. If there is any ambiguity as to what I mean when using words like;

- System
- Ordered
- Cool
- Heat
- Pocket

Point it out and I shall explain. I was trying to make my explanation at the same time precise and easy to grasp, but for the power of linguistics and my application thereof. :sadnod:
Quote from: Ecurb Noselrub on July 25, 2013, 08:18:52 PM
In Asmo's grey lump,
wrath and dark clouds gather force.
Luxembourg trembles.


Asmodean

#34
Yes, but not really.

They are not talking about closed systems in a conventional sense. You can see it by them using language such as "well-insulated." That's not closed - that is a system that is either bleeding energy ever so slightly (By virtue of being well-insulated), and/or absorbing it. (In a closed system, the expression would, if anything, have been "perfectly insulated") [Upon re-read] Actually, why even bother with that? They are talking clearly and specifically about heat and/or mass transfer into the system. You don't enter the room through a closed door. Case closed. Still, having written a paragraph or three... Keep readin' ;-) )

I think they are being creative with their language, defining a closed system as a clearly-defined set of physical and/or mathematical boundaries, rather than in terms of its interactions. For instance, you could say that a car is a closed system like that, its scope defined by the outside boundaries of its body and wheels, even though it absolutely is not - being susceptible to cooking your baby on a hot summer day, among other things.

A closed system is any system that does not interact outside itself. As such, the example provided is one of an open system.

As a quick aside, a closed system may still do stuff within itself. The example I used of pockets of increasing entropy was towards that end. Imagine a box, within which you have a battery, a motor and a fan. The battery powers the motor, turning the fan and generating heat. If no heat (or, energy) escapes the box and no outside heat enters its interior, then said interior is a closed system, subject to global entropy increase. (Your motor may be heating up, literally speaking, but your battery is expanding "useful energy resources" it cannot recover from within the system, eventuially leading to its practical heat death)

[Common EDIT] There may be a few [EDITS] tacked onto these posts to try and clear up ambiguities as I spot them on re-reading. I find this stuff rather intuitive, and so in explaining it, I'm somewhat prone to falling into broadly similar linguistic holes as the author of the above article seems to have done. Bear with me if information gets tacked on while you try quoting from or responding to the post)

[Case in point] On an unrelated note, I never realised that I was, in fact, one of them engineers-engineers, but I am, am I not..? Kinda' thought of myself as a glorified code monkey with a fancy title, if anything, but really I do do this sort of stuff with a wrench and a script rather than a chalkboard and a simulator. Never thought of it this way.

This is cool! Might ask for a raise, I think. :smilenod:

The Asmo wanders off, idly whistling Ritt der Walk├╝ren, being almost-disgustingly pleased with Himself. (The key is to vibrate the... Root of your tongue, I suppose it is - kind-of like gurgling "in reverse," for the opening notes. Makes you sound a bit like one of them ball whistles)
Quote from: Ecurb Noselrub on July 25, 2013, 08:18:52 PM
In Asmo's grey lump,
wrath and dark clouds gather force.
Luxembourg trembles.

zorkan

Okay, so the body is an open system.
When I'm in the mood I'll take out my brain and examine it, then put it back.
A closed system does not expel matter, but I'll try to take it out.
Seems like this disagrees:

https://fs.blog/entropy/#:~:text=More%20specifically%2C%20the%20second%20law,least%20stay%20the%20same).%E2%80%9D


Asmodean

#36
No, it does not disagree. It says, in so many words in the text your search highlighted, even;

Quote from: link above"as one goes forward in time, the net entropy (degree of disorder) of any isolated or closed system will always increase (or at least stay the same)."

Indeed, the entropy of a closed system increases as exemplified in my previous post.

A human body is indeed an open system. By virtue of being so, it can "stave off" entropy for a few decades. Your example of taking out a brain is, I'm sorry to say, nonsensical. A system is not defined as open by the external availability of its subsystems. I have previously provided you with good examples of your body interacting with its surroundings every single day.

You breathe and eat
You piss and shit
You walk and lie
You live and die

My attempts at poetry aside, you can think of your body as an opaque box. Energy goes in - waste and potentially work comes out.  Whether said box has a spleen or can extract its own liver bears precisely zero relevance to it being an open system. It has inputs and outputs. You don't get much more open than that. (I suppose you can consider it as mouth being your input port while your arms and legs and such like are your output ports and your butt hole is your exhaust port)

[EDIT] Also, since according to you,
Quote from: zorkan on February 08, 2024, 02:25:04 PMA closed system does not expel matter, but I'll try to take it out.
...Why is there more carbon dioxide in your breath out than what you breathed in? Where does the extra carbon come from?
Quote from: Ecurb Noselrub on July 25, 2013, 08:18:52 PM
In Asmo's grey lump,
wrath and dark clouds gather force.
Luxembourg trembles.

zorkan

Thanks to your doggerel, I don't think we're too far apart, but I'll make this point.
Any system on earth gets its energy from the sun.
Yet all life is doomed because of entropy.
However much we try to replace lost energy with food we will fail in the end.
Food is of lower grade, having been expelled by other life systems.
If an engine is constantly maintained, it will still fail at some point.
Even towering buildings fall down eventually, no matter how well maintained.





billy rubin



Given that most people struggle with legible handwriting already, the added complexity of cursive is an unnecessary burden. It is more practical and efficient to stick to standard print writing.

Asmodean

#39
Quote from: zorkan on February 09, 2024, 12:39:31 PMThanks to your doggerel, I don't think we're too far apart, but I'll make this point.
I've been known to wax poetic. Literally, on occasion. ;D

QuoteAny system on earth gets its energy from the sun.
Yet all life is doomed because of entropy.
Yes and no. There are systems on Earth that do not (practically) get their energy from the Sun. If speaking of the biosphere, it's mostly true to the degree where you could reasonably call it Solar-powered. The planet itself is an open system. That's just a technical point though - for the purpose of this discussion, I buy what you are selling. Now, on to the more interesting nuances.

Life isn't doomed due to entropy per se (as life) - and this is where we start getting into them subtle distinctions. A hypothetical perfect perpetual motion machine would not be subject to entropy from being in motion. Any other sort would need some sort of external energy reservoir or, like the box I used to illustrate a post or two above, its batteries will eventually run flat. Living things being open systems, they act like that box, except with a charging port. Their components do decay, however, but that decay is not necessarily a measure of the entropy of those systems to the degree where said entropy could be pointed to for an "explanation of death."

[EDIT:]TLDR: Life suffers a different kind of death (Stops being alive) long before it ever dies a heat death.

QuoteHowever much we try to replace lost energy with food we will fail in the end.
Yes - and that would have happened much quicker if we were the way we are, except with no holes to shove full of inputs. :smilenod: While not precisely an example of entropy in itself, it is a good illustration for what entropy means.

QuoteFood is of lower grade, having been expelled by other life systems.
Mmh... Yes and no. Meat can be viewed as "enriched grass" in the sense that its energy density (Joules per kilogram) is higher than that of grass. Fat - even more so. Practically, what this means is that you would need more than a kilo of grass to grow a kilo of muscle or store a kilo of fat. Though I do not know the exact numbers, that discrepancy may be orders of magnitude.

It is not so much you and me specifically, who are subject to "death by entropy" in the "classical" sense - or, heat death - while we live, since we do stave it off by inputting energy. We die a different sort of death. It's more a matter of saturations, attenuations and such like in our subsystems - the loss of the ability to convert dead animals, so to speak, into living cells in a manner which preserves or advances us as a system. Entropy there is a much more subtle property in things like, for instance, a DNA molecule being more likely to "break" over time than to "improve" and the limitations in systems in place to account for and mitigate that likelihood.

In a way and in the right sort of conversation, you could compare aging to entropy, but not because the second law of thermodynamics says so - it is being obeyed. It does not dictate.

[EDIT:]Example towards the above; if you were so inclined, you could technically use dead humans as fuel for your furnace. Useless as a human - perhaps. Plain useless? Not yet. You know, it started as a nice and humorous, easy to digest example, but it did go dark in a considerable hurry, didn't it..? *Sigh...* Insert a jew-in-the-oven joke here. :sad sigh:

QuoteIf an engine is constantly maintained, it will still fail at some point.
It will, and much like a human, it will not die a heat death when it does - it will just turn useless at doing what engines do.

I think I would rather call that decay than entropy, though there may be poetic reasons to use entropy as a general metaphor for it.

I suppose I should also mention that "heat death" does not necessarily mean "absolute cold" of a perfect void - it refers to a state of the system where "none" of its thermal energy can be converted or transferred in a way that "makes a difference" - "stepped down" in exchange for work, if you will.

[Common EDIT] It turned into a bit of a soupy post. I think the matter of disagreement here is, if anything, terminological. If you invoke the second law of thermodynamics, the scope of the word entropy in that setting is narrower than if you use it as a poetic example of decay (Though the opposite works better - exemplifying entropy through decay) - not dissimilarly from the scope of the word "theory" being different when invoking "gravity" vs. when speculating on why that couple over there *point* split up.

So, entropy in terms of thermodynamics is, simply put, the measure of useful energy.
Death in terms of entropy is heat death rather than "his brains have rotted."
An open system in terms of physics is externally interacting - a closed one is "externally inert."
The laws of thermodynamics are defined within specific parameters. That is not to say that they are only obeyed within those parameters, but additional variables (such as the input of energy) need to be specifically accounted for. (For example, by redefining the scope of the system until the energy source falls within it)
Quote from: Ecurb Noselrub on July 25, 2013, 08:18:52 PM
In Asmo's grey lump,
wrath and dark clouds gather force.
Luxembourg trembles.

zorkan

If you believe that god created man in his image, then god must also be subjected to decay and death according to the laws of thermodynamics.
Is god an open or closed deity?
Why did god bother to create over one trillion galaxies when only heaven, earth, sun, moon, humans and their food would do if all his people are here on earth?

Statistically, the 2nd law is an inequality.
That also appears to question god's perfection.
Why would god allow his cosmos to burn up in a heat death, leaving only radiation at some point in the future when the very last star has flickered out?



 
 

Asmodean

Quote from: zorkan on February 09, 2024, 04:47:07 PMIf you believe that god created man in his image, then god must also be subjected to decay and death according to the laws of thermodynamics.
Indeed. a believer would likely say something to the tune of "but God is special. He's all godly and stuff and faith."

Still, providing no reasons beyond personal conviction for it being so is... Thin. If god is "beyond" the universe, then by what means does he itneract with it enough to know when you covet your neighbour's wife? If god is the universe, then will your eternal life in his heaven turn into the worst kind of hell for countless eons before finally "everything" dies a "permanent" death?
 
QuoteIs god an open or closed deity?
If His Majesty the King poops, one must assume that god does too. I'd say open. :smilenod:

QuoteWhy did god bother to create over one trillion galaxies when only heaven, earth, sun, moon, humans and their food would do if all his people are here on earth?
In case he grew bored with a experiment. Just go to a better planet - it's already there. :smilenod:

QuoteStatistically, the 2nd law is an inequality.
If I understand what you mean by that, then no. The second law og thermodynamics is still obeyed in a perfectly-balanced system - it's just inert for all intents and purposes.

QuoteThat also appears to question god's perfection.
Why would god allow his cosmos to burn up in a heat death, leaving only radiation at some point in the future when the very last star has flickered out?
When the last star has flickered out is "just the beginning" of heat death of the universe. Black holes will endure long past that point, and after they have evaporated or gone boom, it will take "incalculable" years for the universe to be reduced to a void with an occasional low-energy photon, timelessly zipping along, with nothing to interact with in any meaningful way.

I think "why" is the wrong question here - it's subject to the whims of a potentially-irrational creature. For what it's worth, if I had the power to fart out a universe of my choosing, it would not be eternal either.

It's possible that the universe will meet a different fate, or on a different sort of time scale. There are some very interesting questions there. Do protons naturally decay? Does the universe exist in a flase vacuum and may therefore be subject to vacuum decay? Such like.

In my admittedly-atheist opinion, such questions are way bigger than the puny gods of humanity.
Quote from: Ecurb Noselrub on July 25, 2013, 08:18:52 PM
In Asmo's grey lump,
wrath and dark clouds gather force.
Luxembourg trembles.

zorkan

QuoteIf god is "beyond" the universe, then by what means does he itneract with it enough to know when you covet your neighbour's wife?
If god is on the outside looking in, then god is both inside and outside according to your view that all systems are open.
Here's the proof:
https://www.amazon.co.uk/Whats-Eating-Universe-Cosmic-Questions/dp/0241459850

"In the constellation of Eridanus there lurks a cosmic mystery. It's as if something has taken a huge bite out of the universe, leaving a super-void. What could be the culprit?"
Why, god!

Asmodean

That's not proof - it's a link to a book.

Unless you mean to say that a statement by authorirty (In this case, a random published author. Note that in this context, the "true greats" would also be "just random published authors") is somehow proof of something beyond that they wrote or otherwise made said statement.

What is the proof? Is there a process I can repeat? Is there a prediction I can verify?

Also,
Quote from: zorkan on February 13, 2024, 12:02:05 PMIf god is on the outside looking in, then god is both inside and outside according to your view that all systems are open.
no, absolutely not. There exist closed systems and even then It is perfectly possible to be fully outside an open system just as it is to be fully outside a closed one. Now, if something is both inside and outside, then there are mechanisms by which that something interacts with the system. If you read my question, I think you will find that it was "what are these mechanisms?"
Quote from: Ecurb Noselrub on July 25, 2013, 08:18:52 PM
In Asmo's grey lump,
wrath and dark clouds gather force.
Luxembourg trembles.

zorkan

God is everywhere, yet nowhere.
Above and below, I hope you know.
In the inner core of the earth and in the great void of space beyond the furthest galaxy.
He knows your every movement and every thought.
If you believe this, you have been bought.