Entropy: Two Simple Ideas Behind Our Best Theory of Physics

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Our most robust theory of physics so far seems to be #thermodynamics
Here are two simple assumptions behind statistical mechanics, the small-scale detailed description of thermodynamics. #statisticalmechanics #entropy
The Second Law of Thermodynamics essentially states that heat (or more precisely, thermal energy) cannot be transferred spontaneously from a colder object to a hotter object. Instead when two objects of different temperatures are brought into thermal contact, thermal energy will spontaneously flow from the hotter object to the colder one until they both reach equilibrium at some temperature between the two objects' initial temperatures. This is the Clausius description of the Law.
Statistical mechanics is the study of particles making up each system we study (such as a gas). This small-scale study allows us to make very precise predictions of how the system will behave. However, it is very difficult due to the often huge numbers of particles in each system. So instead we need to find ways to link the small scale statistical mechanics theory to the large scale thermodynamics theory. Thermodynamics is the study of heat and energy within systems on a large scale (such as an entire gas, liquid, or solid).
The first assumption of statistical mechanics is that each microstate for a given system (each possible energy arrangement of particles within the system) is equally like as all the other possible arrangements. This is the Law of Equal A-Priori Probabilities.
The second assumption is that each microstate corresponds to a large-scale property of the system, such as volume, pressure, or temperature. It also states that we should be able to link a measured property of a system with the weighted average of individual microstate properties over the measurement period.
By the way, Boltzmann discovered the equation linking omega (number of microstates) to entropy, and hence the understanding of entropy as disorder. Since the entropy of the universe increases over time, it is thanks to his work that we know how the universe will (probably) end - in a highly disordered state.
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Timestamps:
0:00 - The Second Law of Thermodynamics and Entropy
3:04 - Sponsor Message - Check Out Brilliant.org in the Description
4:14 - Microstates of a System
6:03 - The First Assumption of Statistical Mechanics
7:50 - The Second Assumption of Statistical Mechanics
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[@ParthGChannel]

Hi friends, thanks for watching! Also a huge thanks to Brilliant for sponsoring this video. To try everything Brilliant has to offer-free-for a full 30 days, visit brilliant.org/ParthG/. The first 200 of you will get 20% off Brilliant’s annual premium subscription. As always, let me know what other topics I should cover in future videos!

[@pavangaonkardonigadde]

You stand out in KZbin physics because you explain equations along with just explaining.. that is amazing thank you

[@abelgerli]

Statistical thermodynamics blows your mind if you start to understand it. Boltzmann was genius by sticking to the idea with the origin in statistics and probability. Love it.

[@chrstfer2452]

And then its only backed up by the efficacy of the schrodinger equation and its extensions (eg dirac, GED, GCD). No model has better predicted experimental results than QCD, and that model and all models derived from schroedingers QM imply many worlds as an infinite set of identical timelines at time t being distinguished at time t+dt by a new observation being intersected with a measure-theoretic filtration of the world lines at time t so that the intersected set become the new current universe at time t+dt.

[@chrstfer2452]

(The measure theoretic framework of stochastic processes applied to the problem of "collapse" as interpreted by everett)

[@abhishekanand7376]

Sadly he suicided after not getting enough support for his ideas on theory of gases

[@tuanhungang5621]

thanks a lot parth G, love your channel so much !

[@hadassahemmanuel6136]

hello parth , I'm so glad to come across u r channel. if time allows you please make videos on the solid state of physics and atoms and molecular physics

[@TerryBollinger]

Nice quick intro to thermodynamics!

[@mariotabali2603]

You re becoming very good at explaining.

[@williammorton8555]

Good video but I have a bit of a quibble. Defining Entropy as the increase of "disorder" is a bit misleading. A better definition: Entropy is an increase in the number of observable possible states of a system. For example, a system of four markers in a 2 x 2 grid has 24 different observable states. A system of four markers on a 3 x 3 grid has a considerably greater number of possible states. However, if you keep the four markers in a fixed state relative to each other the number of observable possibilities drops to 4 in the 2 x 2 grid but it's 16 in the 3 x 3 grid. To an observer sitting on one of the markers order is maintained while the move from a 2 x 2 grid to the 3 x 3 grid increases the entropy.

[@sureshkumarshanmugam4749]

Brilliant!!!

[@brenlee9325]

Important point

[@alanziryan4625]

Post more videos, you are good at teaching, and can you make a video about superstring theory?

[@Yashhh02]

Parth bhaiya, I'm totally in love with you videos ! I always get inspired to study more. Could you please make a how "you" study and learn physics and maths ? That would be great

[@parthtomar1009]

I am also parth and i love physics

[@infinitegaming44]

I don't understand how the velocities of gas molecules are figured out. Can you please make a video on Maxwell Boltzmann distribution of velocities. Or can anyone explain this to me

[@user-qj3rv2mo1b]

Does brilliant offer industry recognized certification in PLC programming, Oracle SQL and Oracle DBA, or any one of them ?

[@chunmunstudy4454]

Can you please explain caesium frequency?

[@stephenmarshall5529]

Entropy (dispense with "disorder"): matter and energy spontaneously tend toward equilibrium, a process which cannot be reversed without the input of energy from outside of the system. .

[@morgengabe1]

I think it would be worth not relying on absence of spontenaity. It's like trying to grab what you say you can't touch. Let it be spontaneous, leverage that to raise entropy. You might like Anderson's absence of diffusion in certain random lattices.

[@kuloodaldanhani8452]

Try making videos about angular velocity , periods , frequency, and tourque … andddd rotational stuff . It will help other 11th year students survive cuz I’m coming in to my end year and I wish someone would guid me to wake up , I’m currently studying so wish me luck

[@TerryBollinger]

@alanziryan4625, regarding superstrings, my comments below are unlikely to help much in your primary interest in finding a good visual tutorial intro to superstring theory. Still, the history and origins of superstring theory in 1960s accelerator physics form a story that gives important context and is interesting in its own right. That story is below. -------------------- If your goal is a grasp of the basics of superstring theory, the best starting point is not the mind-bogglingly complex body of 60 years of math that we now call superstring theory but the original, well-documented, and experimentally rock-solid _string_ theory of the late 1960s. (Note the absence of the “super” prefix!) Accelerator folks in the 1960s discovered that if you “vibrated” (excited) particles like protons, neutrons, and other particles collectively known as _hadrons_ (heavy particles), you ended up increasing their masses in an extraordinarily regular way. Folks got quite excited when they noticed these mass increases used a quantized version of the same equations as the vibrating strings of musical instruments. From this, many speculated that the _interiors_ of protons and neutrons were “pure math” rather than xyz space and that this underlying math had the same mathematical structure as vibrating strings. This pure-math hypothesis was known, a bit cryptically, as S-matrix, for “scattering matrix.” This matrix gives the probability of generating new particles when two entities collide. A few folks introduced the _super_ string hypothesis into this pure-math S-matrix environment. The idea was simple: Just as the interiors of protons and neutrons seemed to be composed of pure string vibration math, there might be a similar but deeper layer of pure math responsible for all the other non-hadron, point-like particles in the Standard Model, such as electrons and photons. These particles would then seem point-like only due to the minimal size of the new “super (small)” strings. So how much smaller than proton strings are they? About 20 orders of magnitude. For comparison, if you expanded a proton to the size of an earth, one of these superstrings would be as long as about 150 ordinary protons end to end. That’s _small!_ (Ironically, the postulate that no test would ever prove or disprove the existence of superstrings proved not _quite_ to be true. Just a few years ago, extreme-gamma analysis by the HAWC group proved superstrings are too large and clunky to implement the degree of spacetime smoothness required for the most extreme forms of cosmic gamma radiation. The superstring theory community, shocked by this damning body of new evidence showing their mathematics cannot represent the physical universe, immediately held a community-wide press conference admitting their error… just kidding, they ignored it. Working for that many decades without paying attention to _any_ kind of experimental data becomes an entrenched habit even when directly relevant data _does_ arrive.) Getting back to superstring origins, in the 1970s, the idea that electrons and photons might also have a string-vibration-like representation similar to hadronic strings sounded very promising at the time. However, the more important driver for the superstring hypothesis was a desire to resurrect and re-implement a discredited 1930s idea by W. Pauli and M. Fierz called the _graviton._ But why would they focus on a _disproven_ idea? While the answer is not “42,” it turns out that it _is_ “2.” That’s the number of spin units added in accelerators every time they excited a hadronic state into its next higher iteration, and, coincidentally, it was also the number of spin units hypothesized for the hypothetical Pauli-Fierz gravitons. That sounds like a bad joke when stated this way, but in that period, the simple phrase “2 spin units” in both descriptions convinced many folks that gravitons _must_ be real despite earlier failures. They wanted to make gravitons real, so they set the size for the new string-like vibrations at 20 orders of magnitude smaller to match Pauli-Fierz graviton scales. If the main reason to propose a new level of _super_ strings was to represent gravitons, what were these gravitons, and why did folks want (and still want) them so much? A Pauli-Fierz graviton is a photon-like particle designed specifically by Pauli and Fierz to mimic the behavior of Einstein’s gravity - not implement it, but mimic it. Is that not the sentence you expected? Please read on. I said “mimic” because the first thing Pauli and Fierz did in their papers was _require_ the space on which their gravitons moved to be flat. The “duh” obvious problem is that the moment you insist on this entirely arbitrarily flattening of spacetime, you, in effect, kick Albert and General Relativity out the window and replace him with a quantum-by-definition, graviton-mediated mimic of actual gravity. Remove the arbitrary flat-space constraint to see why this is a pseudo-gravity force. When you curve the space, the true Einstein gravity returns, and the graviton version becomes a redundant gravity mimic riding on top of it. Gravitons thus never were, and still are not, related to Einstein’s actual topological gravity. Not surprisingly, the Pauli-Fierz idea quickly led to inconsistent mathematics and was mostly abandoned a few years later. This earlier well-justified abandonment of gravitons is one reason I find the intense refocus on them since the 1970s deeply baffling: Gravitons, _by design,_ cannot answer the question of what Einstein’s curved-space gravity is. While I don’t think this was always true, most folks interested in physics these days tend to assume the opposite: gravitons _necessarily_ “merge” general relativity and quantum mechanics and, thus, are the key to unifying all of physics. Alas, they are not, which makes this a sad hope indeed. Regardless of that popularity, gravitons, by definition, neither explain Einstein’s curved-space gravity nor connect to it meaningfully. But then, the superstring idea gave the old gravitons a new life, so perhaps this skewed focus on a non-existent, not-explanatory pseudo-gravity force is not totally strange. It’s a necessary hitchhiker on the supergravity hypothesis. (End of part 1 of 2. See reply below for part 2 of 2.) (a PDF copy of this 2023-05-16 comment is available at sarxiv dot org slash apa)

[@TerryBollinger]

(Begin part 2 of 2) So what are the statuses of hadronic strings and superstrings these days? The reason you’ve probably never heard of hadronic string theory is simple but ironic. The strings doing the vibrating turned out to be _completely real_ and composed of what we now call the strong force. Unlike the electromagnetic and gravitational forces, the strong force stretches and snaps like a bungee cord. With quarks necessarily attached at either end, these strong-force strings rotate and vibrate “just like” vastly large strings in musical instruments. In both cases, the source of the string-like math was, well… strings, just of very different sizes. There was never a shred of “pure math” inside protons and neutrons, just the universe’s smallest and most energy-intense real strings. The superstring theorists never got the memo. They continued as if _pure math_ was the only thing needed for superstrings, despite the quark and strong force theories having made that hypothesis untenable. The correct path would have been to propose a _new_ force, one remarkably similar to the strong force but 20 (!) orders of magnitude more powerful. They should also have proposed two or three entirely new particles to carry the charges of this new force and use it to bind themselves together. Finally, despite the enormous energies involved, they had to do this in a way that left almost no net mass. In the case of photons and several other particles, they had to leave no mass at all. That level of more hands-on physics theorizing was too much for the almost entirely math-focused community that quickly emerged around superstrings. To my knowledge, no one in superstring theory circles even bothered to try. They kept asserting it was all pure, beautiful math and adding more. And more. And _more._ In 60 years, these pure-math superstring ideas never generated _one_ lab-testable idea, though they did generate enormous numbers of unverifiable equations. And, of course, there’s the sad but overlooked point that the HAWC space-is-smoother-than-superstrings data showed the entire superstring concept to be incompatible with special relativity. That is also one of the most surprising features of superstring fascination: It’s necessarily an _aether theory_ that violates special relativity. To be fair, all current variants of field theory are also frame-bound aether theories, but that’s a different problem. What’s surprising is how one proposes to fill _all of space_ with an incredible number of tiny, insanely energetic vibrating “somethings” and _not_ notice that this also creates a frame-dependent aether. That’s what an aether _is:_ a space filled with lots of little “somethings,” such as atoms or fields, that hold energy and carry waves. Einstein’s theory of special relativity, taken at face value and without qualifications, remains one of the best-proven theories in history. Folks should take it more seriously, especially when proposing theories about the deeper nature of space and time. Also, when reading about superstrings, you may encounter confusing claims that a mathematician “invented” them decades after their well-documented origin in the 1970s. This event was a promising math-only twist that, at the time, seemed at the time to breathe new life into pure-math superstring speculations. Alas, after decades of noisy papers later, the idea only ended up making the entire area vaguer, broader, and, remarkably, _less_ predictive of actual physics. That latter point about too much noise is why I’ve made no effort to “explain” all of the dimensions, curves, branes, and such of superstring theory. Very good observational (HAWC) data says they don’t exist, so it’s best not to take non-physical and deeply noisy paper literature seriously. Beautiful noise is, after all, still just noise in sheep’s clothing. In sharp contrast, the hadronic strings were and continue to be entirely real. However, in isolation, such proton-scale strong force strings have no more to do with gravity than the pseudo-gravity particles Pauli and Fierz first proposed almost a century ago. Gravity is _topological,_ even if “topological” is, itself, a statement needing deeper analysis and linkage to particle physics, quantum physics, and the underlying nature of space and time. A final note: Folks talk about an AI “singularity” a lot these days. Permit me to observe that another singularity is approaching quickly, and it’s likely to be a doozy: The abrupt collapse of a wide range of “noisy,” energy-indifferent, points-are-real math models in physics. Condensed matter and energy physics should do fine, but a _lot_ of math and most physics theory in its current forms won’t. The Real Math Singularity is all about shedding noise-generated complexity, not loss of prediction, and it revolves around the need for a deeper understanding of how all space and time emerge from matter, as opposed to the decades-long physics point of faith that it’s the other way around.

[@deltalima6703]

Tldr

[@TerryBollinger]

@@deltalima6703you are so right, this guy just _can't shut up!_ :)

[@BytebroUK]

Parth, you make good vids. Sometimes though (maybe YT vid lengths or whatever) I feel like you've laid the table, but then I'm still hungry when I leave :)

[@fior2373]

How does antimatter interact with two dimensional space?

[@Delta._]

I am sure G in Parth G means GOAT (GREATEST OF ALL TIME)

[@sugandesenuds6663]

hes the GOAT, The GOAAAAAAAAAAAAAAAAAAAAT

[@physicist-G]

Bhai tu India se he?

[@YToVSTRoX0]

Are you aware of Arieh Ben-Naim's works on entropy ? There are several books. For instance "ENTROPY: The Greatest Blunder in the History of Science". He has very strong views on the matter to say the least. His approach is probabilistic and he is very dismissive of views such as S being a measure of order/disorder. Have a look to his explanations.

[@pauldirc..]

What are his views

[@krishnadaskr4656]

Very happy to see someone mentioning Ben-Naim's books. I have read almost all of his books on entropy, and I can say with utmost confidence that his explanation of entropy is THE ONLY CORRECT one! And, he literally DEMYSTIFIES the concept of entropy. If any of this youtubers making such baseless, fancy videos in this subject would read and understand Ben-Naim's books, they will surely delete such comic videos from their channel!

[@holytrinity2510]

The concept of “nothing” cannot have the ability to act, otherwise it would exist as a “potential act” and be one of many things that exist. If the universe came from “nothing” then this nothing would have had the ability to become the universe. But the concept “nothing” as we previously explained, cannot have the ability to act, therefore, the universe could not have come from nothing on its own. Since there are things that do exist, then “something” must have always existed, because as we just proved, things cannot come from “nothing” on their own. If time had ever proceeded at an infinite rate, which is like fast forwarding through a motion picture, we would not be here today because all events would have already occurred in a single instant. Therefore, time has always progressed at a finite rate and any mathematician can prove that time could never have progressed over an infinite time interval. The proof goes like this, pick any number no matter how great. You can always add one to it and thereby make it greater in value, therefore you can never reach infinity. And you cannot say that all we need to do is to wait an infinite amount of time and then we would reach infinity, because then you are assuming that you can wait an infinite amount of time. However, this is what you were trying to prove and so that is not proof at all. You cannot assume to be true, that which you are trying to prove to be true otherwise you can prove anything to be true, even that which is false. Therefore, time could not have started an “infinite” time ago and therefore had a beginning a finite time ago. Since “something” always existed as we previously proved, it had to have existed before time started. Since space and time are one entity called the space-time continuum as Einstein pointed out, then this “something” had to have existed before space and time existed and therefore caused space and time. Since this “something” existed outside of space and time it cannot be made up of material things, because material things can only exist in space. And this “something” could not be just chaos which has no order, because as we previously proved, something cannot come from nothing on its own, hence order cannot come from pure disorder. Therefore, this “something” had to have had the ability to cause order, space-time, material things, beauty, life, everything in our universe, including our universe and natural laws and rules. Since we call ourselves beings, then we should at least call this “something” a Being, who we call God. Since only God always existed, and the universe is not made of God as we just proved, then God must have created the universe out of “nothing”. Since “nothing” does not even exist, then God must have infinite Power in order to have created the universe from “nothing”. Since all people desire happiness, then God must have created us to be happy out of love for us. Naturally, all creatures should love their Creator. For us to love God from our heart, God had to create in us a free-will, because no person can be forced to love, otherwise this would not be true love from their heart. With our free-will, we can choose to do good or bad to our neighbor and this is why there is sin in the world, because some people have chosen to hate God and their neighbor and are only interested in pleasing themselves. God did not create evil, nor does He desire evil, but he does allow sin to happen because He had to form us with a free-will, in order for us to love Him and others from our heart.

[@SorbetCitron17]

Your god has broken my heart at one year old and keep making me face emotional and practical dilemmas to just ultimately erase me and everyone I have loved (and I have loved). If time runs one way and two things can't be true at the same time. I m being sacrificed everyday without hope. Is that a good God or a demon? I m not asking for money but I see entropy being higher for me than people around me, supposedly because I cause it being a sinner (mostly in thoughts and judgments). I m punished for eveyone's sins but I can't even state they are sinning. Like a good demon, I ll have to try to exist on their graves and it is sad because I wanted friendship and acceptance. And believe me if the weirdness around me does not account for science in its current state as being unfinished, I don't know what does and my observations are a way to go forward. I ll never be listened too. I ll never be believed. I might not even get to overcome my own chaos to get the message through If people were not traping me in conundrums legal, emotional, physical asking square when I offer round. They could have their mind blown and both love it and hate it. Alone, I m powerless. Yet, people only accept me if I praise my hell.

[@bloodyorphan]

Not if you are looking from the skin or space side ... All particles are just holes in space, something that is cold has more redshifting space around the aperture, so the photons redshift to a lower temeprature. The hotter particle will share the colder particles' aperture space until equilibrium is achieved!. Which implies that space is in fact the shared medium not the "heat" ;-) **Einstein**

[@barababu1773]

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