Why does time only move forward? This simple question has no simple answer. Join the journey following the answer
By Oren Farber, Hamad'a
We are looking at a video in which a ball moving on the table is projected at a constant speed. Can we say for sure that the video is playing from start to finish (as usual) or maybe it is playing from end to start? It turns out that if the friction is negligible, we have no way to decide. What about a falling ball? Here too it is impossible to know, since it is possible that in the original video the ball was thrown upwards, and in terms of the physics of free fall (in the absence of air resistance), an upward throw and a downward drop are expressed by the exact same equations.
What about a broken glass, explosion or collision? In cases where the 'correct' direction of the flow of time is clear: fragments have never been observed that would fit into a glass, or a new car that would emerge (to the delight of the insurance) from its crushed fragments. Countless other examples can be given: heat does not flow spontaneously from a cold place to a hot place, you can turn eggs into omelettes but not omelettes into eggs; Ice cubes melt, but water does not freeze at room temperature. These examples illustrate a central aspect of the arrow of time, and create in us the strong feeling that time has a direction.
More on the subject on the science website
Following this we can ask, what exactly makes a process irreversible in time? That is, what processes will seem unlikely (or impossible) when we project them from the end to the beginning? In a more general formulation: do all irreversible processes have a definable common denominator? It turns out that it is, and the answer to this is given in the framework of a branch of physics called statistical mechanics that grew out of the theory of thermodynamics.
The key to defining the time reversibility of a process is related to the concept of 'entropy' which can be interpreted as the degree of 'disorder'. This is a popular and inaccurate interpretation, but there is some truth in it. According to this definition, the entropy of a complex puzzle is smaller than that of a scattered puzzle and the entropy of a whole glass is lower than that of a broken glass; If we imagine the arrangement of the atoms in space, we can say that the entropy of an ice cube (very ordered) is smaller than that of the same mass in a liquid state (less ordered), which is smaller than that of water in a gaseous state (very disordered).
Statistical mechanics was more precise and interpreted entropy as "a measure of the number of microscopic states that create a distinct macroscopic state". There is only one state of a 'solved' puzzle, but many states of a mixed puzzle - therefore assembling the puzzle is a process in which entropy decreases. Similarly, an omelette has greater entropy than an egg because there are more ways to arrange the atoms that make it up into states that we would define as an 'omelette' than microscopic states of an 'egg'.
And here is an interesting thing: it turns out that in our world spontaneous processes tend to increase the degree of entropy or disorder. This can be illustrated by an example: if we do not pay attention to order, the desk in the office will become messier, the garden will become neglected, and the pieces of the puzzle will remain scattered on the floor (and maybe lost around the house). It is true that it is possible to lower the degree of disorder locally, but this will lead to a greater increase in the degree of disorder of the environment. For example, you can put water in the freezer and thus lower its entropy, but the heat produced by the refrigerator will cause a large increase in the entropy of the gas molecules in the room (bad news for those who thought it was possible to use the freezer as an air conditioner). In general, the total entropy of the universe (or of a closed system) is increasing with time, and this is one of the formulations of the second law of thermodynamics - a deep and fundamental law of nature, which no evidence has yet been found to disprove.
By the way, lowering the entropy locally is achieved by the flow of energy from the environment into the system. The refrigerator, for example, cannot lower the entropy of the water without a constant supply of energy from the electricity company. Similarly, the entropy of living bodies is relatively small (high level of organization), thanks to homeostasis processes that regulate the absorption of energy from the environment. When these processes stop, the body dies and decays, that is, its entropy increases. In the language of thermodynamics: "From high entropy you came, to high entropy you will return"
From now on say: lowers local entropy
And this brings us to the common denominator that was sought before for all processes that are not reversible in time: in all of them the degree of disorder (or entropy) increases and therefore the opposite process (decrease in entropy) is very unlikely. Why 'unlikely' and not 'impossible'? Well, as strange as it may sound, processes in which entropy decreases spontaneously can occur. To understand why, imagine a closed container in which gas molecules are homogeneously distributed. Since each molecule has a speed and a direction, theoretically a situation can arise in which all the molecules (and there are many) will be directed to the left corner of the box, thus the entropy will decrease. Why would such a thing happen? There's really no reason, but it's theoretically possible. Even if we sit a monkey in front of a computer and let it randomly hit the keyboard, it could theoretically produce a Shakespeare play. The chance of this is unfathomably zero, so it simply won't happen. This is exactly why entropy does not decrease in spontaneous processes.
Such crazy randomness is demonstrated in Bangkok Insurance's elaborate advertisement:
http://www.youtube.com/watch?v=aS7rJyFQezo
The subtext is of course, "It's possible, but you wouldn't want to rely on it..so get insurance! "
To the Ministry of Finance's pension website courtesy of the photo in this article
To Oren Farber's blog Science and other spirit
117 תגובות
Israel
It certainly could be. My feeling is that practically - we are really alone, but on planets similar to ours, there is at least a simple life. Don't forget that with us too, most life forms are unicellular.
I already said - we are quite alone.
I already said - we are quite alone.
There is a very low probability that there are many other planets with life like ours.
Israel
Smiley - you are right.
A molecule that replicates? You are wrong. We already have a few that are approaching what is thought to be a life form.
If you have an idea for another source of life - I would love to hear it.
You don't need trillions of atoms, even if you find a simple smiley face on some planet, you will know that someone created it.
: )
Israel
We don't know what the first replicator was, and it may not have been very complex. In any case - this is a single molecule, and not a pen that contains trillions of atoms.
And in addition - chemistry is not a random process. Therefore, it is difficult to talk intelligently about probabilities and entropy.
It turns out that the entropy of a replicating cell - an extremely complex mechanism - is higher than that of almost any inanimate object: a pen, a pencil, a key, a nail, or the pair of letters T.
Well Schwinn, but don't be surprised that many smart and intelligent people no less than you have a hard time accepting it.
Israel
In English Wikipedia it says:
"There is no single, generally accepted model for the origin of life. "
That is, there is no one model that the majority agree on. This is true.
If you want to specifically understand the Hebrew text, I suggest you contact the author of the entry.
This duplicate of yours - he can perhaps explain what Wiki says:
"Despite this, to this day we have not found a complete and plausible explanation for the formation of that primordial living creature, and this is despite enormous progress in understanding the development of life and the ancient Earth."
Israel
I guess the drop in the first duplicate is much lower than in the pen.
And by the way, there are things whose probability of occurrence is exactly 0.
The probability, by the way, is always greater than 0 - it's just a question of how long even a phantom will spontaneously form.
(Much..).
So is it possible to conclude from your words that the decrease in entropy in the case of spontaneous creation of a replicating cell is smaller than the decrease in entropy in the case of spontaneous creation of a pen?
Israel
I qualify the subject of the pen - it is possible that every part of it could be formed spontaneously, and then the parts will coalesce.
That is, the probability is not necessarily 0.
And of course a person created "spontaneously" can build the pen...
Israel
Yes.
Let's get to the point.
Are you claiming that a pen - or a pencil of a pen - or a word written with a pen - cannot spontaneously form during the lifetime of the universe but a cell can reproduce?
Israel
Where did you write that the system is closed?
Chemistry is not random. If you mix several atoms together of all kinds, certain substances will be formed, depending on all kinds of conditions. These are not inert pool balls that can line up in any random shape.
In the case of the pen - it can be assumed that the oxygen will always combine with the iron, and plastic materials will not be formed.
It is also possible to make it easier for you: when your maid arranges the house, then its entropy decreases..
So what is meant by "entropy always increases in a closed system"? If she can get off whenever she wants?
And if she indeed can - then how do you agree that a Rolex pen cannot be created spontaneously (a mistake by the way, it can, it just needs a long, long time...).
Israel
1. Do you agree with the following sentence: the chance of entropy decreasing in a system of the order of Avogadro's number in a period of time equal to the lifetime of the universe is almost zero.
No, I don't agree. If we take a cloud of gas in space, gravity can cause a decrease in entropy. If I forget to empty my irrigation system in the winter the water will freeze - decrease in entropy. If I boil water, dissolve salt in it until saturated, and let the water cool - we will get a decrease in entropy (crystallization).
2. Do you accept that the formation of a cell that can reproduce itself from inanimate matter (hereafter "primordial soup") is a decrease in entropy.
Yes, I agree with that. The formation of a crystal is also a decrease in entropy.
You finally wrote a correct sentence "I really don't understand what he is asking or suggesting" and didn't jump straight to (wrong) conclusions as usual.
1. Do you agree with the following sentence: the chance of entropy decreasing in a system of the order of Avogadro's number in a period of time equal to the lifetime of the universe is almost zero.
This is the claim of the commenter, a Technion student, who by the way is not a student but a (long time) graduate whose field of expertise is entropy
2. Do you accept that the formation of a cell that can reproduce itself from inanimate matter (hereafter "primordial soup") is a decrease in entropy.
Israel
You wrote "a Technion student, who understands a thing or two about these subjects, believes that the probability of the spontaneous formation of a single cell capable of replicating itself in the 13.7 billion years of the universe is extremely low."
And you also wrote "So how did we come into being spontaneously without a creator without a cell that replicates itself?".
I wrote that the first replicator was probably not a complex cell (like a bacterium), but something much simpler. Therefore - the argument for the lowest probability is not relevant.
I also wrote that there are several hypotheses for the first replicator, but we may never know if one of these hypotheses is what started our life.
So - I really don't understand what he is asking her, or suggesting.
What discussion are you talking about, is there a discussion here?
In the discussion, the parties are supposed to listen to the arguments of the other side and refer to them, not to invent the arguments of the other side.
Earlier you claimed that I was trying to prove the existence of God. Denying? show you where? Did I claim such a thing?
Now you say that I agree that what the Technion student commenter claimed is nonsense. Where did I say that?
So why do you need me here, anyway as always you make up what my arguments are and then answer them.
Oh I forgot, understanding Hebrew and what is called is not something today..
Israel
There is no point in this discussion. You mentioned a sentence of some student, and you agreed that he said nonsense. So now you're debating the meaning of each letter?
Can you explain why this is a straw man argument?
Maybe something like your last explanation "There is only one reason to say that this cell must have formed randomly: you are trying to "prove" that God exists."
Israel
It is unlikely that a pen would be created without a creator.
If there is no claim that a single cell is randomly generated, then your sentence:
"A single cell replicating itself in DNA in 13.7 billion years is lower than low as a student claims from entropy considerations - so how did life on earth originate?"
It is a straw man argument.
Accepts, accepts, doesn't really understand what the connection is. I don't think anyone here does.
What about my question? Can a Rolex pen be created by itself without an external creator?
Israel
Are you going to answer my question or not?
As one who admits that his Hebrew is not exactly a past language, and who writes a clever sentence like "There is only one reason to say that this cell must have formed randomly: you are trying to "prove" that there is a God", I would think a few times before I would write "even more slowly" and the rest Plznita It just makes you sound more ridiculous.
Take for example what you say:
You wrote "In short - we are probably quite alone in the universe."
Now you say you didn't write it?
Of course I wrote and also explained:
"If the probability of the spontaneous formation of a single cell that replicates itself in 13.7 billion years is lower than low as a student claims from entropy considerations - then how did life on earth originate?
Or maybe the answer is trivial: it is lower than the lowest in Israel - but if we take many billions of planets where the conditions exist for the creation of life, then the probability that life will indeed be created in one of them becomes the highest of the highest.'
So for those of you who have difficulty, here is a numerical example: if the probability of a single cell replicating itself spontaneously in the DNA in 13.7 billion years is one in a billion - lower than low - then if you have a billion earth-compatible planets, then the probability that a replicating cell will form in one of them is almost certain. And if there are a trillion such planets then there will be around a thousand planets with a good chance for life, not to mention if there are infinity.
Still, we're pretty much alone because if only one planet in a million matches Earth, and only one in a billion has life formed, then only one in a trillion planets has life. But this is very far from saying that we are alone in the universe.
Capish?
Between us, do you understand what the claim of a Technion student is? Or what is a straw man anyway?
Let's start with something simpler: could the computer you use - or even the keyboard - or even a Rolex pen - have been created in the universe without an external creator, from a primordial soup of molecules and forces of nature like those that you claim, as I understand it, existed in Israel billions of years ago years and out of them the first replicating cell was created and this without an external creator?
Israel
wow even slower???? 🙂
I will try…
Do you accept that science does not claim that a replicating cell is created randomly? It means a cell that includes a shell, a nucleus and so on.
Israel
You wrote "In short - we are probably quite alone in the universe."
Now you say you didn't write it?
"If the probability of the spontaneous formation of a single cell that replicates itself in DNA in 13.7 billion years is lower than low as a student claims from entropy considerations - then how did life on earth originate?"
This is a straw man claim.'
Why?
"You said that we might be the only life in the universe."
where?
Israel
I have to make sure to explain to you more slowly, and tell my reactions...
You wrote "If the probability of the spontaneous formation of a single cell that replicates itself in 13.7 billion years is lower than low as a student claims from entropy considerations - then how did life on earth originate?"
This is a straw man claim. You didn't invent it, nor that smart student from the Technion. Nor did Hoyle and Wickramasinghe invent it, although they were the ones who did the calculation….
You said we might be the only life in the universe. This is a problematic claim because (at least 2 reasons). The first is that if the universe is infinite then there is no way to test the claim. The second is that life may be relatively common, but not at the same time. Perhaps it is really unusual that life in our country has survived for 3-4 billion years, and many times it survives much less.
And one more little thing - chemistry is not random. Such a calculation has no meaning.
What is my straw claim?
Hebrew once again..
Israel
The popular claim is that replicators were created much simpler than bacteria. There are several hypotheses as to why the first replicators were, and there is no need to raise this straw man argument over and over again.
Too bad you don't read links...
It's pretty clear why I wrote this: I don't know what the answer is, that's why I asked.
If the probability of the spontaneous formation of a single cell that replicates itself in DNA in 13.7 billion years is lower than low, as a student claims from entropy considerations - then how did life on earth originate?
Or maybe the answer is trivial: it is lower than the lowest in the country - but if we take many billions of planets where the conditions exist for the creation of life, then the probability that life will indeed be created in one of them becomes the highest of all.
In short - we are probably quite alone in the universe.
Israel
Hebrew is not my mother tongue, so I apologize in advance.
I said that there are several possible (natural) explanations for the formation of life. I also said that whoever claims otherwise is trying to sell something - and usually, he is trying to sell his religious belief.
You started the discussion with "a Technion student, who understands a thing or two about these subjects, believes that the probability of the spontaneous formation of a single cell capable of replicating itself in the 13.7 billion years of the universe is extremely low."
A child in the XNUMXth grade knows this, so that student who understands, did not say something exactly innovative. So why did you write it?
This whole Hebrew thing is hard for you, huh?
Take someone - 8 years old or older - and go through the thread with them. This will help you avoid scams in the future.
Hint: You wrote: "Although I think there is another possibility: "As usual you did not specify what the possibility is..."
But the full sentence I wrote is: "Although I think there is another possibility: I am trying to understand how a cell capable of replicating itself was created from nothing." So technically at least, I mentioned what the possibility was, didn't I?
Well, it's getting a little more creative than usual. Understand - good. You won't understand - that's also good.
Israel
You wrote "Although I think there is another possibility:" as usual you did not specify what the possibility is....
You throw out one sentence from Wikipedia, again as usual - because you are trying to prove what you believe in, instead of trying to contradict...
So - read you https://en.wikipedia.org/wiki/Abiogenesis - and answer me the following question: Do you think all these explanations are wrong in your eyes?
And besides - what is the explanation you offer? I'd love to discuss something interesting, rather than have a quote war.
In Si'ata D'Shemiya Elit Ali.. Indeed, the agent of holy books is your servant.
But I am not alone in my struggle. My good friend - Vicky - says about the "origin of life":
"Despite this, to this day we have not found a complete and plausible explanation for the formation of that primordial living creature, and this is despite enormous progress in understanding the development of life and the ancient Earth."
Could you send this sentence to a forensic linguistics lab and find the difference from what I'm saying?
Hypotheses.. ideas.. what about findings and facts, nephew of a spider?
And what does the sentence mean: "And you are the one who spins." You said that today there is no explanation for the beginning of life, and because of this, you offer another explanation' - what other explanation did I offer Nisimino? Did we start Golog Golog a little earlier than usual today?
Thirty prostrations and ten recitations of Shema Israel, maybe I will grant and forgive.
Sabri Maranan.
Israel
Open Google and search. You can start with Wikipedia, but there is a lot of information about it.
You can read about the Cairns-Smith hypothesis, about the ideas of Manfred Egan, about amyloids, about the world of RNA. And there is more and more.
Use the following method:
1. Look for what you don't want to find
2. Check the reliability of what you found.
And you are the one who spins. You said that today there is no explanation for the beginning of life, and because of this, you offer another explanation. I said that whoever claims there is no explanation is trying to sell something.
Miracles, cousin of the iguana, haven't we changed a little reason and spin?
You are the one who claims there is an explanation, so you are the one who should bring it and convince. I say I don't know of one.
If you don't bring then I also have an equivalent argument: letters Sal - attracts energy of abundance and livelihood. See:
https://www.eol.co.il/articles/40#
Shouldn't that convince you too?
Israel
Let's be precise - I claim that there are smart people who claim to have such explanations. That is, there is no single explanation.
I know some of the explanations, because I researched the topic several years ago as part of a master's thesis. That should convince you … just like giving me a quote from Michael should convince me…. Maybe just use Yehuda's attitude "it doesn't seem to me", and close the matter? 🙂
I also need to be precise in what I say - you don't necessarily need to find a single molecule that replicates. It is very possible that this is a small group of different molecules that replicate together.
So you claim that there is an explanation for how a cell capable of replicating itself was created from inanimate matter.
It is interesting. Michael - you can find some of his comments in the thread below - said if I remember correctly that there is still no explanation and that it is a mystery.
So maybe Michael is also a dos in the closet like me?
Israel
Yes. But note two things:
1) The first replicator was not a cell as we know it today, but a much simpler molecule.
2) We do not have the "explanation" for the beginning of life on Earth. We have several possible explanations, and perhaps one of these describes what really happened.
Nissim, do you claim that there is an explanation for how a cell capable of replicating itself was created from inanimate matter?
Israel
So I'll say it for the fourth time: no one claims that a cell was formed by a random process. It is likely that there are relatively simple molecules that know how to replicate (this is more than likely....)
That's what I do? Oh well, so be it, so I'm trying to prove that there is a God..
there is a God!
Although I think there is another possibility: I am trying to understand how a cell capable of replicating itself was created from nothing.
Israel
Let's assume that it is true that there is one primordial cell from which all living things are descended. There is only one reason to say that this cell must have formed randomly: you are trying to "prove" that God exists.
What about crystals? Don't they reproduce on their own sometimes?
No matter how you roll it, you'll end up with a cell that knows how to replicate. Without it there is no life, and it doesn't matter what the stages were before.
Israel
Life did not (probably) start with a complete cell, but with the simplest thing that knows how to reproduce itself.
We don't know what it was - not because we have no idea - but because we have a number of hypotheses and today we have no way of knowing if one of these hypotheses is the one that really describes the beginning of life, or perhaps a hypothesis that we didn't think of.
assembly? Let there be a rally.
So how did we spontaneously come into being without a creator without a cell replicating itself?
Israel
There are 24 ways to arrange 4 cards. In one of them the order goes up and in one the order goes down (4 assembly). Binomial is not relevant.
Who says there is a claim that a replicating cell is created randomly? Only dark creationists….
24 or 12? Please wait, let it be 24 or 12..
binomial elk..
24 or 12!
A Technion student, who understands a thing or two about these subjects, believes that the probability of the spontaneous formation of a single cell capable of replicating itself in the 13.7 billion years of the universe is extremely low.
Israel
Excellent explanation! Only instead of 16... it's 24 (or 12).
Moses
The second law is fundamentally statistical. If you open a new pack of cards it is in a state of entropy 0 when every color is arranged in it from the smallest number to the largest. Shuffling will mess up the package and therefore increase its entropy. But from time to time what is called fluctuation of probability will occur, and the mixing will actually arrange the pack - you can try it with 4 cards and you will see that if you mix them, then one time out of 16 they will arrange themselves in ascending (or descending) order.
This does not contradict the second law. As hard as it is to accept this, it is also possible that the formation of life from inanimate matter is just a fluctuation of probability, and there is no divine intervention or any higher power involved.
Moshe Cohen
The second law only holds when there is no external energy source to the system.
Look at a lived-in city versus an abandoned city, or even a single building. Without work, the second law "dismantles" everything.
a question:
"Heat does not flow spontaneously from a cold place to a hot place" and vice versa - its lava will radiate its heat to the environment and ... will solidify into a rock with a lower entropy. This is also the forecast for our universe - it expands and cools, from a soup of elementary particles, to atoms, through gravity and nuclear fusion to heavier atoms, scattered gas clouds to more organized stars and galaxies and galaxy clusters. When substances cool, they crystallize and in crystals the entropy is lower - water molecules in an ice crystal are much more ordered than in liquid which is more ordered than steam which is more ordered than plasma. is not it?
That is, there are spontaneous processes that increase the degree of order and decrease entropy, including the big bang? How does this fit with the second law of thermodynamics?
point:
That's not what I felt.
I felt that I gave all your claims a winning answer and you did not answer this answer.
If you say it's water grinding then it's a shame, in retrospect, for the effort I invested.
Michael, we stopped at one point or another in the debate, not because of agreement, but because it reached a state of water grinding, all the claims I made remain, and I did not see that anywhere you really answered them, you only presented your position, and sometimes there is nothing to argue about positions because it is enough" This is due to a different mental order of priorities.
point:
It is not wise to talk in headlines.
Tell me which of my arguments you don't agree with and point out what you think is wrong with them.
If you cannot do this and still do not agree - tell me why the conclusion does not follow from them.
Hand waving has no value.
Quantum mechanics presents nature as non-deterministic in any accepted sense.
Of course, there is the new refuge that you resort to at every opportunity, but in the conventional discourse - what happens in nature is what is defined as the absence of determinism.
Einstein did not believe that there is no determinism but that is because at the time the lack of determinism had not yet been proven.
Several things have happened since then and Bell's Law is one of them.
I don't know how you bring Boehm into the matter, but if you already brought Boehm in - the following is a quote from the mouth of Yakir Aharonov - Boehm's partner in a large part of the research (as appears in the interview he gave to the last issue of Odyssey): "The quantum revolution proved that, contrary to what we thought and believed, the world The microscopic is not deterministic. It does not behave in the way that classical physics thought it should behave. It has a high level of inherent uncertainty. Quantum theory states beyond any doubt that when it comes to small particles their behavior cannot be determined with certainty. This was a revolution."
You have to be precise in terms, many people are confused by this and don't know what to think. Quantum mechanics is indeed deterministic in the sense that the equations are derivatives of time (although partial derivatives but still the solutions are functions of time), quantum mechanics is random as the general public has heard in the sense that it is not possible to predict what the result of a certain measurement will be and here there are 2 main approaches: that the wave functions collapse, or they evolve into all possible states.
The randomness in quantum mechanics is about the first approach where it is not possible to predict where the functions will collapse, but is it true randomness? Einstein and Bohm thought not. The rest think so. I generally think that this mechanism does not work that way, and that surely there is a reason for everything, and just as correlation does not prove causation, neither will a lack of correlation prove non-causality.
On issues of consciousness, existence, evolution, randomness, etc., we disagreed...
point:
Regarding response 54:
Definately not.
Your words have no basis in this response.
Precisely in your deterministic world a reason is necessary for everything (and even then there was no need for there to be God and even then the question would have been asked what is the cause and even then it was possible to describe an infinite series of reasons and even one that all enters in a limited time) but in the world of quantum theory there is not even a need for a reason. This is exactly what characterizes this theory: you can observe two neutrons that are identical in everything and yet they will not decay at the same time and there is no reason in the past that causes one neutron to behave differently than another.
point:
I definitely think the laws of math apply regardless of the world.
I don't think it is possible for a world where these laws are not true, but even if there were, I have no doubt that there is no point in discussing such a world because if we talk about such a world we will not know what we are talking about.
It is still not clear to me what subjects you mean in your words in response 50.
If this is true then you should also believe in God as the cause of causes, because if there is a world and there is an effect and a cause then you must be a primary cause...
It seems to me (uncertainly) that you hold a Platonist approach, for example that concepts exist, that the laws of mathematics are valid regardless of the world and all kinds of claims like that...
Michael, I always responded to your words, maybe here and there I didn't notice and missed one thing, but I always tried to respond to your words...
point:
No.
I thought the fact that you stopped responding to them indicated agreement.
If there is something you do not agree with, please respond to my last response on the same topic (indicating the number of the response you are referring to).
Haha, did you notice that we went through several topics, without any agreement?
: )
point:
This is the last attempt to explain this unimportant thing to you (it is unimportant because, as mentioned, nature has built-in randomness, so it is not important to analyze what would have happened if it had not existed).
The laws of probability and statistics give correct predictions even in large systems with language conditions that even if they were completely defined would be "like random".
This is the reason why election models interest us even after all the people have voted and before all the votes have been counted (a situation that is clearly deterministic because the entire result has already been determined).
Michael, when you have a defined position at a certain time of each particle, then it is called an ordered state (if they all move straight or each in a different direction is meaningless, and it is only to illustrate that entropy should not increase), and since this is the case in classical mechanics, then the increase in entropy is not explained next to her.
point:
You just go into corners that are of no importance and it seems to me that it is really a waste of the discussion.
You can describe a great many scenarios that did not occur in nature and say all kinds of nice things about them and still - these things will not be natural phenomena because the starting point was not like that.
For one reason or another (and it really doesn't matter what, although it is clear that the inherent randomness of quantum theory played a part in it) the particles in nature are not all arranged on one straight line but are scattered in a way that is random for any practical need (both in terms of location and in terms of other characteristics).
From this moment on, the laws of probability can be applied to them.
No matter how you look at it, the increase in entropy is not a fundamental law of physics but a result of other laws/initial conditions when the laws of mathematics are applied to them.
Michael if you send a million balls straight they will keep moving straight. If they started out ordered they will continue to be ordered, the laws of probability are not smooth on non-random processes. Therefore, classical mechanics cannot explain an increase in entropy.
So the likely possibilities are that quantum mechanics is responsible for this either by the collapse processes, or by the multiple worlds.
point:
Let's start with the fact that, as you eventually said yourself - the laws of physics are not deterministic and there is a built-in randomness in nature that stems from the uncertainty principle of quantum theory.
Beyond that, the behavior of normal large systems that do not have any randomness can also be predicted according to the laws of probability and provide good predictions.
Entropy benefits from both worlds: both from the fact that nature is indeed random at the particle level and from the fact that it is made up of too many particles.
Therefore the probabilistic prediction predicting entropy growth is valid in nature.
Michael, the laws of physics are deterministic, and the theory of probability does not apply to them (the theory of probability talks about something with a random component), the laws of physics are reversible, contrary to the fact that entropy increases (in this sense the increase of entropy contradicts the laws of physics we know).
Obviously, the line of thinking is that there is some quantum effect (collapse of functions) that is the random factor that allows distributions to manifest as the laws of probabilities say.
point:
That's just it!
There is no physical explanation for this because it is not a physical law but a result of the laws of physics when the laws of mathematics are applied to them, including probability!
The laws of mathematics (including probability) do not depend on the world and are true in every possible world.
Time is a dimension. Through the human, physical glasses, it is seen as a straight and linear line but from different angles things are seen differently.
Is it possible to prove that different events from different times do not happen at the same time and affect each other??
Michael, there is no physical explanation for entropy increasing. In the world, the physical laws and not the probabilistic laws rule (which turn out to work precisely to explain the laws of thermodynamics and statistical mechanics in the macro, but there is no physical explanation for this yet)
http://en.wikipedia.org/wiki/T-symmetry
Addendum to Abi Mesika:
The fact that the theory of relativity does not rule out going back in time does not prove anything.
This theory also does not rule out the claim that ingesting cyanide is good for health.
Avi concludes:
You firmly state that there is no such thing.
What do you base your claim on?
The scientists use the phrase "the arrow of time" because they feel it has meaning.
We do not have a single example or proof that time does not advance.
As demonstrated in previous responses - quantum phenomena also show the existence of the arrow of time - whether it is the kaons or whether it is the collapse of the Hegel function (these are, in my opinion, much more serious proofs than entropy which in my view is nothing more than a result of the progress of time and not the cause of it).
1. There is no such concept as the "arrow of time" in physics, although physicists also tend to use it. In all physical equations (in mechanics, electromagnetism, gravitation, quantum, astrophysics, etc.) in which the time variable t appears, t- (ie minus t) can be placed in its place and they remain unchanged (except for two exceptional cases).
2. The feeling that time moves forward is unique to biological systems (like the human body) and not to physical systems and this has nothing to do with the entropy explanation that appears.
3. As Einstein taught us time (actually the product of the speed of light in time, ct, is altogether another dimension like length, height, width, XYZ, which is difficult for us to grasp intuitively. Therefore, as we do not ask why it is not possible to go back in the length X dimension The same goes for time. Indeed, the theory of relativity allows for the possibility of going back in time……
point:
The increase in entropy is not a result of a physical law but a result of probability.
The claim that consciousness exists in a world where entropy increases is just as true as the claim that consciousness exists in a world where there is someone named Benizri who thinks that earthquakes are caused by meshab zakor.
Would you dare to conclude from the fact that there is one such world that it is necessary for consciousness?
So it's true - Benizri is not found everywhere in the world, but hey! Nor does entropy increase everywhere in the world. On the contrary - precisely in the human body it is small!
The consciousness we know is always in a world where entropy increases (and yes I'm talking about the idea of multiple universes) so I assume that consciousness can only exist in such a world for some reason...
Michael, the laws of physics are non-probabilistic, there is no physical reason for entropy to rise and for processes to be irreversible, but the effect of probability can be obtained if there is a split into many worlds (the split does give room for combinations and probabilities).
point:
This is a very strange claim.
What are "worlds where entropy increases"?
Why did she grow up in these worlds and not in others? Do the laws of probability not apply in others?
If at any point in time the world splits into many worlds (as the classic claim of the multiple worlds claims, but it is impossible to understand from your words whether you are talking about it or something else) then any given world in which the entropy has increased up to this moment, can split into a world in which the entropy is a little smaller. Will life in this new world stop? Even if the entropy decrease only lasted a tenth of a second and then the entropy started to increase again?
My opinion on the matter is that we live in worlds that are expanding at the same time (multiple worlds), and consciousness occurs in worlds where entropy has increased, but this is related to quantum states of the brain, only in worlds where entropy has increased is there consciousness...
In conclusion, time does not pass, consciousness is defined by passing through time (hundredths of a second) in a world where entropy increases.
Hello,
First, let me apologize for the English, it's hard to find a Hebrew layout around here.
Entropy is a measure of disorder/complexity of a system and it's true that the second law cannot be violated (as far as I know)a.
All, of our definitions of entropy hold on a micro/macro level systems, but I'm afraid that we cannot assume it on the entire universe, for a couple of reasons:
1. Someone mentioned that entropy holds under constant volume, lets assume that the matter volume is constant since, how are you going to define dark matter since visible matter is only a small fraction of the content of the universe. We don't know enough about it.
2. We know the shape of the universe and the fact that it's expanding, but what if (being devil's advocate) it expands to a constrained volume (like smoke in a bottle).
Also, there are multiple definitions of entropy, depending on your regime of interest.
On his letter to Godel, Einstein wrote that because of the asymmetry of time, time traveling isn't possible. I'm not sure about EM asymmetry.
It was a nice article, too bad it had a very simple example to a very complex issue.
Not sure if my post helps with anything, just a few random thoughts.
AA
Moshe,
Refer to Avshalom Elitzur's book 'Time and Consciousness' pages 63-72.
Eddie
These asymmetries from both of you to the Young Mills fields are non-equilibrium calibration fields and this has nothing to do with a preference for the direction of time
Roy,
The author asks about a common denominator that irreversible processes have. His answer "turns out to be yes, and the answer to this is given within the framework of a branch of physics called statistical mechanics that grew out of the theory of thermodynamics. The key to defining the time reversibility of a process is related to the concept of 'entropy'…” etc. etc.
So that's it, it's not. There are processes that do not belong to statistical mechanics. Such processes are completely irreversible, and there is no probability whatsoever (even a very tiny one, as might occur in the example of the gases according to the Poincaré-Lieuville assumption). They testify that the arrow of time is completely irreversible, regardless of statistical mechanics and thermodynamics.
Eddie, you wrote a lot of smart things…
Too bad I just didn't understand what you wrote and how it relates...
Adam builds:
I don't think there is any chance of that being the case.
These are people with completely different levels of understanding and also with different degrees of willingness and ability to read what they are commenting on and really try to understand what the writer meant.
guess:
Boltzmann, B5 and Bigumbom
They are the same person.
Entropy is an important concept in the context of the arrow of time, but it is not the only key. In my opinion, the more correct context is the context of asymmetries. In my opinion it is difficult to say that time is just a dimension, similar to the dimensions of space. There is something truly irreversible about it.
I would like to focus not on the asymmetries of the psychological, biological and thermodynamic arrow of time. but in
- Electromagnetic asymmetry - Electromagnetism (EM) is defined using Maxwell's equations, which from a purely mathematical point of view allow both the existence of waves propagating from the source to space-ZA in the direction of the future, and also of waves converging from space to the source-ZA in the direction of the past. But in reality - only one type of wave appears, the one that propagates into space ZA in the direction of the future.
– the quantum asymmetry; The interaction of a particle with a macroscopic body causes a transition from the quantum superposition to a defined state. The transition from superposition to position due to wave collapse in the case of 'measurement' is unidirectional; There is no reverse transition of a particle defined in position to a state of superposition.
- Asymmetry that appears in the weak interaction - the asymmetry associated with symmetry - CPT: the breaking of the right-left symmetry (that is, the P symmetry) as well as the C symmetry, although CP symmetry will usually exist, but not always - as was discovered for particles of the Kº meson type, in which CP symmetry was broken Thus, only the symmetry TPC can save, if it is assumed that there is an asymmetry of T, which balances the other two asymmetries, and restores the overall symmetry. Such an asymmetry of time was indeed discovered in the decay of particles of the meson type Kº, which is asymmetric in time; If it is projected from the beginning to the end or from the end to the beginning - there is a difference between the real process and the reversed one.
Unlike macroscopic asymmetries, which can be attributed to unfavorable initial conditions of the system, here it is a fundamental interaction of particles, for which no plausible explanation can be found, and the asymmetry cannot be attributed to unfavorable initial conditions of the system.
It can be said that nature, already at a very fundamental level, differentiates between past and future, thus creating a difference between time and spatial dimensions, in which symmetry does exist. Therefore it is difficult to say that time is just a dimension, similar to the dimensions of space.
I did not refer to the cosmological asymmetry and the gravitational asymmetry - in principle, these topics are quite speculative, in the current state of scientific knowledge.
It is possible that time is also going backwards, but we will not feel it
Because in practice there is no process of subtracting information, these are only adding information.
As when writing a document in Word, every action that is performed, including deletion, will only add information and not delete the old one, even with a deletion operation, the file grows...
It is possible that time is also going backwards, but we will not feel it
Because in practice there is no process of subtracting information, these are only adding information.
As with writing a document in Word, every action that is performed, including deletion, will only add information and not delete the old one, even with a deletion operation, the file grows.
Boltzmann:
True, it is not based on statistics and its entire function is to allow the statistical calculations to give significant results in the future, that is, to base the prediction of the future on the most recent information we have and that is the existing situation instead of on information that has passed its time which is some situation in the past that in the meantime has developed and arrived without us being able to predict it exactly in advance, to the current situation.
Michael:
Absolutely agree, the second law is a mathematical theorem. But your claim that entropy has decreased is not based on statistics.
Boltzmann:
In my opinion, whoever sees the second law of thermodynamics as a physical law and not a result of statistics is simply wrong.
Michael:
"... it has no use if it only discusses the distribution of possible states of the world when it stands alone and its only use is in presenting the current state..."
This is exactly where the ergodic assumption comes in, which makes it possible to replace the average of the possible states with the average of a single state over time. (note - "over time", not "at any given moment")
"...in this situation it is customary to say that entropy has decreased." Who says?
As I already wrote, the Poincaré-Liouville theorem guarantees a return to the initial state, and if the entropy is indeed small we will get a contradiction to the second law of thermodynamics (which many consider to be one of the most basic laws in physics).
Boltzmann:
My words may seem a little confused to you, but I will risk saying them anyway.
The whole idea of incorporating the concept of entropy into physics is meant to explain the fact that we find the world as we find it and to allow us to make predictions about the future.
It has no use if it only discusses the distribution of possible states of the world when it stands alone and its only use is in presenting the current state of the world against the background of the distribution of possible states and our ability to predict the future state based on the current state.
The fact that in a given room where all the air molecules were concentrated at one point, after a while we find them more or less evenly distributed is explained by the tendency of entropy to increase, but there is no point in talking about the continued increase of entropy if by chance the molecules returned and concentrated at the starting point. In this situation it is customary to say that the entropy has decreased even though it is only one case out of a whole distribution in which the entropy actually increased.
When we talk about the growth of entropy, we are talking about what is expected to develop when we leave a given situation.
What is expected to develop from a situation where all the molecules are concentrated at one point does not change as a result of the fact that this is the second time that the molecules have been concentrated at the same point, therefore time has passed and the entropy is necessarily greater.
In fact, all interesting probabilities in relation to the future are conditional probabilities (where the condition is the existence in the present of the state in which the system is in the present).
Michael:
Entropy is a quantity defined on a mathematical distribution.
Entropy is not defined on a single state of a dynamic system but on the distribution of states.
Therefore, by the way, the Poincaré-Liouville theorem does not contradict the second law of thermodynamics.
Let's take another sentence (which is wrong) from the article:
"The total entropy of the universe (or of a closed system) is increasing with time"
Regarding the universe: the universe does not fulfill the ergodic assumption (the fact that it expands prevents any such possibility). Therefore it makes no sense to claim that the entropy in the universe increases with time. One could argue that the entropy of the collection of all possible universes increases over time, but that is a different argument.
I have no complaints against the writer, entropy is a concept that is misinterpreted by many good people, including respected professors.
Moran:
Although the idea is not discussed in the article, it obviously belongs to the topic.
As you will see, it is discussed here:
http://www.physicsforums.com/showthread.php?t=49222
From the little that I know, it seems to me that the collapse of a wave function is a process that is irreversible in time.
Boltzmann:
In my opinion, your claims against the author are not justified.
Entropy is a concept defined for a closed system that does not interact with other systems (it is true - and no one claimed otherwise - that this is a system that has many components that function in many ways as separate systems).
If it were possible to build a room that is completely isolated from any influence of the outside world, there would be room to talk about the entropy that prevails in that room.
Although it is technically impossible, but mathematically, and for the purpose of illustrating an idea, this is definitely a situation that should be considered, and in this context, all the author's words are correct and justified.
B5:
I have not yet read the full discussion that developed here, but the answer I gave was complete and included an answer to all the reasons you raised in your question in favor of the strange claim that it returns us to the world of the observer and the effect of the observer on particles.
When someone makes a completely unsubstantiated claim there is no reason to answer the reasons he did not make.
You asked a question that had no basis and it seems really strange to me to try to invent one or another basis for it (probably in my opinion it is a wrong basis) and explain why it is wrong.
Smart answers can only be given to smart questions.
Ergodicity is a mathematical property of a dynamical system. In free formulation: a dynamic system is ergodic if (regardless of the starting point) the system visits the entire possibility space equally. The meaning (and also an alternative definition): average over all system states = average over time for one system.
The ergodic theory is a developed mathematical branch and is mainly concerned with proving that certain dynamical systems establish the ergodic property.
Statistical mechanics also exists without ergodicity (as the study of clusters of systems), but usually we want to apply statistical mechanics to a single dynamic system (for example, a gas in a closed space) and then we must assume ergodicity. In practice, proof of ergodicity for physical systems does not exist, so the assumption remains As a discount only.
Regarding Liouville's theorem (more precisely, the Poincaré-Liouville theorem): a volume-conserving dynamic system (volume in the state space, all energy-conserving systems are like this) operating in a finite space (compact, in mathematical terms) must return (at a certain time, unknown) to the state Very close (close epsilon) to the initial state if we wait a long enough period of time.
Boltzmann,
The topic of ergotism is interesting, could you expand a little on that as well as the Liubil theorem?
Butzelman, what's going on?
There is a point that tends to be overlooked in the discussion of entropy: ergodicity. According to statistical mechanics, entropy is a quantity that is attributed to a collection (one can think of a statistical collection) of systems and is meaningless for a single system. The ability to relate entropy to a single dynamic system (an example of such a system: reality as perceived by our senses) stems from the principle of ergodicity: a dynamic system tends to behave (statistically) over time as accumulated systems.
The problem with the ergodic principle is that there are many systems where the ergodic principle does not apply, for example if you look at biological systems. For example, on Earth during the last 5 billion years entropy seems to be small - life appeared and created order out of disorder. There are scientists who sanctify the principle of the increase of entropy (the second law of thermodynamics) and find all kinds of complicated explanations for the appearance of life without the decrease of entropy. The correct explanation is that entropy is not valid for such systems (unless you look at an accumulation of systems, such as all the possible histories of the earth).
The author of the article also sins "...processes in which the entropy decreases spontaneously...a situation can theoretically arise in which all the molecules (and there are many) will be directed to the left corner of the box.." (By the way, there is a mathematical theorem by Leoville that proves that under certain conditions it is guaranteed "... and thus entropy will decrease" - here is the mistake - entropy is never attributed to a momentary state of a single system.
BS:
Shabbat Shalom.
To your question: no.
What you are talking about is about quantum theory and a system in which there is superposition, meaning that the system is practically (at least according to the theory) in two or more states.
In thermodynamics, on the other hand, you talk about a number of statistical possibilities that you can arrange the system, i.e. theoretical states, but the system itself is in one given state.
An analogy is not the most accurate but quite explanatory, think of a matrix or a system with a number of holes in which you can be a ball.
Quantum theory talks about how there can be several balls in a number of holes - when the balls represent photons for example, and the holes are solutions to the Schrödinger equation for the photon's location (sorry for the digs on Saturday morning)...
Thermodynamics will strive for a state where you will have as many holes as possible but still one ball - that is, you will have as many options as possible to arrange the system, but it will be in only one state - where the ball is.
Michael:
Answer 2 is very mature and properly reasoned.
Throwing up and falling down are expressed by the same equations even if there is air resistance. The resistance enters the equation as a force in the direction opposite to the direction of the speed (and it doesn't matter what the direction of the force is).
An interesting and well-written article, but as if it stopped in the middle... I would be happy to continue.
To be honest, I didn't read the article, but it's a great advertisement...
B5:
To your question: no.
An interesting article on a fascinating topic.
The arrow of time is a mystery because our personal experience of the forward flow of time does not find a grip in mathematical equations that describe it - there time has no direction.
Entropy, on the other hand, describes a reality that is very similar to our experience, although it is a statistical reality and not an absolute one, which means for example that there is even a very small chance that the water will suddenly freeze for no apparent reason.
Are we returning to the realm of the observer and his influence on particles? 🙂