I don't believe the 2nd law of thermodynamics. (The most uplifting video I'll ever make.)

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Күн бұрын

Learn more about differential equations (and many other topics in maths and science) on Brilliant using the link brilliant.org/sabine. You can get started for free, and the first 200 will get 20% off the annual premium subscription.
The second law of thermodynamics says that entropy will inevitably increase. Eventually, it will make life in the universe impossible. What does this mean? And is it correct? In this video, I sort out what we know about the arrow of time and why I don't believe that entropy will kill the universe.
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00:00 Introduction
1:00 The Arrow of Time
3:04 Entropy, Work, and Heat
7:07 The Past Hypothesis and Heat Death
9:34 Entropy, Order, and Information
11:38 How Will the Universe End?
15:46 Brilliant Sponsorship

Пікірлер: 5 400

@MrEiht 11 ай бұрын

As Abba said: "Entropy killed the radio star..."

@chris.hinsley 11 ай бұрын

Come on Sabine ! Do another techno pop song ! Please.

@nagualdesign 11 ай бұрын

Abba? I think you mean The Buggles.

@MagnumInnominandum 11 ай бұрын

That was Jefferson No Ship...😮

@chris.hinsley 11 ай бұрын

Don’t get me wrong I love the physics. But “Catching Light” was the bomb !

@jorriffhdhtrsegg 11 ай бұрын

Abba surely not

@mikebarushok5361 11 ай бұрын

I have witnessed water running upwards from a ditch onto a road then becoming airborne and creating a cloud. But, it was because of a tornado passing near to my house and I hope never to see anything like that again.

@SabineHossenfelder 11 ай бұрын

😮😮😮

@Dead-Not-Sleeping 11 ай бұрын

Fascinating! Scary, but fascinating.

@rickmorty7284 11 ай бұрын

💀💀

@benjaminbeard3736 11 ай бұрын

I thought you were going to say mushrooms.

@ultramovier 11 ай бұрын

When water evaporates it goes into the sky to form clouds.

@tayzonday 11 ай бұрын

If I don’t shower, all the good air in a room definitely moves into the corner.

@jdtv50 11 ай бұрын

Chocolate RAIINNNN!

@AttackOfTheTube 11 ай бұрын

Some stay dry

@stevenlayne9227 11 ай бұрын

@tayzonday we definitely have the same algorithm. You keep behaving like a tyrant in the comment sections 😂

@bossoholic 11 ай бұрын

When I don't shower, everybody suffocates and my flowers die

@alexandershendi7428 11 ай бұрын

@tayzonday And if you move into *that* corner, it will move into the opposite corner.

@deebarker1969 Ай бұрын

Sabine, I'm a chemist, and in conversations in the past, I attempted to make the arguments about entropy you've made so eloquently in this video (especially the associations/ideas about order). From now on, rather than arguing, I'll recommend watching your video. Thank you so much for this great video!

@vixeni3365 3 ай бұрын

“and luckily so because it would be inconvenient if you entered a room and all the air went to a corner” just made my day

@truejim 11 ай бұрын

“My videos can only go downhill from here…” The perfect ending to a video about entropy! 😂

@aggies11 11 ай бұрын

Yep, that joke is brilliant and works on so many levels.

@yeroca 11 ай бұрын

The entropy of explanations of entropy. So meta! The explanations can only be as good, and will likely be worse from now on.

@GoDodgers1 11 ай бұрын

She is probably right, not that they were anything special from the start.

@hyperduality2838 11 ай бұрын

SYNTROPY (convergence) is dual to increasing ENTROPY (divergence) -- the 4th law of thermodynamics! Making predictions to track targets, goals & objective is a syntropic process -- teleological. Teleological physics (syntropy) is dual to non teleological physics (entropy). Concepts (mathematics) are dual to percepts (physics) -- the mind duality of Immanuel Kant. Mathematicians create new concepts from their perceptions (geometry) all the time! Noumenal (rational, analytic, mathematics) is dual to phenomenal (empirical, synthetic, physics) -- Immanuel Kant. Mathematics (concepts) is dual to physics (measurements, perceptions). Deductive inference is dual to inductive inference -- Immanuel Kant. Inference is dual. The rule of two -- Darth Bane, Sith lord. "Always two there are" -- Yoda. Subgroups (discrete, quantum) are dual to subfields (continuous, classical) -- the Galois Correspondence. Classical reality is dual to quantum reality synthesizes true reality -- Roger Penrose using the Hegelian dialectic.

@MR-ub6sq 11 ай бұрын

@@hyperduality2838 Yeah

@theprinceofinadequatelighting 11 ай бұрын

"It can only go downhill from here" Sabine's humor, much like our universe, is chaotic.

@truejim 11 ай бұрын

It was a brilliant joke!

@davido.newell4566 11 ай бұрын

Well ordered!

@jonathanbourret2968 11 ай бұрын

I think she meant, "It can only go high entropy from here".

@cdorman11 11 ай бұрын

11:45 "If you stop a random physicist on the street and ask them if they agree..."

@keithwollenberg5237 11 ай бұрын

I wonder if she was aware how funny it sounds to anglophone ears to have someone with a German accent expound the desirability of order.

@Thomas-gk42 3 ай бұрын

To some of your vids, I come back months later again and again, because they are lovely every time new. This is one of them.

@Cre8tvMG 23 күн бұрын

I enjoy your sense of humor keeping things light and entertaining while simultaneously tackling deep concepts. Great blend.

@DrAndrewSteele 11 ай бұрын

Aging biologist here! I’d like to add an uplifting comment to this uplifting video. :) I’m always a bit sad to see entropy given as the reason we get old. As Sabine discusses later in the video, open systems with access to a source of low entropy can use that to decrease their own entropy, so given that we can take in low-entropy food, there’s no in-principle reason we couldn’t use this to keep the entropy of our bodies roughly constant with time. So not aging is totally allowed by the laws of physics! It’s even well within the laws of biology-there are plenty of animals that don’t age, from tiny hydra to giant tortoises, and even one of nature’s most beautiful animals, the naked mole-rat. Their risk of death and disease doesn’t change with time, which basically means they keep their entropy constant throughout their adult lives. Now all we need to do is crack this biological entropy preservation using science…but that’s another story!

@elio7610 11 ай бұрын

Unfortunately, we already have an overpopulated earth so preventing people from aging is gonna exasperate the issue. I would not be against preventing ageing though, even if my life was no longer than normal, a life without aging is far more enjoyable than living with a constant gradual decline.

@DrAndrewSteele 11 ай бұрын

@@elio7610 If you’re worried about overpopulation, I made a video about exactly that which you might enjoy :)

@edcunion 11 ай бұрын

Planaria?

@TitanOfClash 11 ай бұрын

Wow, I can't believe that I ever espoused that exact view. When you put it like that, entropy as a reason for aging makes no sense. Thank you for ridding me of that misunderstanding.

@DrAndrewSteele 11 ай бұрын

@@edcunion I’m not sure if we’ve got any lifespan data on them (happy to be corrected!), but given their regenerative powers I’d not be surprised!

@ToddPangburn 11 ай бұрын

THANK YOU for pushing back against entropy being described as order vs. disorder! Through years of schooling entropy was this poorly defined, almost spooky concept of order. Then I was finally introduced to entropy as probabilities of microstates (with gas in a box), and it was completely logical and clear.

@billschlafly4107 11 ай бұрын

Entropy is to heat transfer what friction is to an object in motion. Entropy reduces the available energy in a system just like friction. Order vs disorder isn't useful at all IMO and only serves to cloud what's happening.

@sjoerdthabozz 11 ай бұрын

Agree. Order is a matter of human opinion. Don’t think nature cares.

@xxportalxx. 11 ай бұрын

I think they're synonymous ways of talking about it, it's just that order as a concept has more to unpack to get to the point. Order means that there are rules that limit the number of microstates. A bookshelf ordered alphabetically has very few allowed microstates (defining the microstates as the books' arrangement), a disordered bookshelf on the other hand would have as many microstates as there are ways to arrange the books.

@blueckaym 11 ай бұрын

I agree! I've always found order & statistical description of Entropy to be fundamentally wrong. And if you look you can see that this approach exists in many other fields of science (of SCIENCE! Which is supposed to be OBJECTIVE :)) The trouble is scientists are not always objective - actually everyone is at least a little subjective at times, that due to our limited resources (at least attention and Time). But how science generally work - you observe a phenomenon, you describe is somehow, you test if your description allows you to predict same phenomenon in the close future; if your prediction fails (or is imprecise) you improve your description until you get accurate enough predictions ... and at this point you KNOW that you best description is the CAUSE for your prediction ... so it's easy to miss the fact that the Universe doesn't give a rat's ass about your descriptions :) It's just one of our many biases - one that many scientists also fail to. Ultimately our descriptions would be so perfect that they'll fit to Reality 100%, and then it would be only a philosophy game to distinguish between the two ... but even with our most precise sciences we're still not there. But people (and esp. scientists) love to believe that the theories they learn (and especially the ones they make) are close to perfect and thus that bias becomes really, really strong! Have you seen a scientist trying to explain some phenomenon by stating some equation and ending with something like "and as the equation tells us, the object has to do this and that". Well sure if your theory and equations are perfect you'll get it right ... except for the understanding part! Very little of such descriptions actually explain anything, and it's exactly because they jump over the actual forces and threat the description as the cause. In that case if your description is for example statistical (which many sciences use today ... and particularly QM) then it's really easy to believe that probabilities and statistics are the CAUSE for things like Entropy! ... but this is still fundamentally wrong of course! :)

@Bryan-Hensley 11 ай бұрын

Kinda like dark matter

@un4given868 8 ай бұрын

Thank you for making clear to me what entropy is and as a bonus giving me a solid idea of what Necessity could mean as well .

@markusk2289 8 ай бұрын

This video reminds me how it always frustrated me in school as well as later at Uni that things were described or defined in simplified ways that made them wrong, harder to actually grasp or both. Sometimes the actual truth of the matter would slowly reveal itself often leading to an „aha“ moment years later and a feeling of „I knew it“. Also funny how oftentimes simply explaining the meaning of a latin or greek term would have almost explained the whole concept behind it, yet somehow no professor ever did that.

@maninspired 11 ай бұрын

I'm a mechanical engineer who focused on thermodynamics in college. Despite years of study and using entropy in formulas, this is by far the best explanation of entropy I've ever heard.

@deltalima6703 11 ай бұрын

Would you agree that entropy is fishy?

@johndemeritt3460 11 ай бұрын

There's a reason my father, who trained as a mechanical engineer but became a computer programmer/systems analyst, always referred to thermodynamics as "thermogoddamics".

@oosmanbeekawoo 11 ай бұрын

Classic response on a video that does not explain Entropy. It's far easier to believe we understand than believe we've been fooled into understanding.

@chrisj5443 11 ай бұрын

My education was the same. I was waiting for her to say entropy tends to increase in a CLOSED SYSTEM, but she never did. She must assume the universe as we understand it is a closed system, but that's very debatable, given the required low entropy at the Big Bang. Also, questioning the semantics of the 2nd Law (the meaning of "order" seems trivial to me. After all, I recall the word "disorganized" being used in the 2nd Law, which is better I think.

@karol_p 11 ай бұрын

She actually makes the mistake of calling heat a form of energy, when in fact heat is a form of energy transfer.

@AlexanderTome 11 ай бұрын

This has brought me closer to reconciling questions I've had about entropy than I've ever been before. Thank you for that.

@whyofpsi 11 ай бұрын

I've made some visualisation that might further enhance your understanding: kzfaq.info/get/bejne/or1ne7dnrt6tj6M.html

@elizabethco6116 Ай бұрын

I’ve been hoping to hear something like this from you. Thank you for this.

@ShipOfFreaks 9 ай бұрын

This is a great philosophical point. I love your subtlety, Sabine.

@shivasive 10 ай бұрын

A friend of mine once said ”if studying physics doesn't humble you, you're doing it wrong."

@PrivateSi 6 ай бұрын

If you don't confidently, arrogantly even, question physics you're doing it wrong... Entropy should be redefined as Simplicity or Uniformity... Complexity can be static and structured, or dynamic (and structured)... Closed systems simplify over time. Energy can increase complexity. This redefinition solves many issues.

@moneteezee 2 ай бұрын

@@PrivateSi You haven't been humbled yet clearly. Entropy has already been defined precisely in physics, from the mid 19th century. What loose definitions you get from science communicators isn't reflecting the reality of this situation, hence you must study physics. (Even this video enunciated this so I truly don't know where your head is)

@PrivateSi 2 ай бұрын

@@moneteezee .. You can either make a new term or change the Law of Entropy, because that law is wrong when over-applied to the entire universe. It's fine for gases in a closed system, but fails as a universal law, unlike my redefinition.. You could call it the Law of Simplicity if you prefer, as long as you stop declaring the Law of Entropy to hold at all times.

@PrivateSi 2 ай бұрын

@@moneteezee.. If fields are real they have to be made of discrete elements that have to be as equidistant as possible throughout the entire field for the field to be empty. This is a perfectly ordered state that's as simple as possible. Hence, The Law of Entropy should not be a law or Entropy should be redefined. It's a simple, logical argument given the evidence for QUANTISED FIELD(S).

@M-dv1yj Ай бұрын

@@moneteezeeentropy is likely the unwinding of quantum entanglement from the source of singular entanglement of all possible quantum expressions into less entanglement limited expressions … it entropy is the cost or the balancing side of the of increased complexity that rebirths cycles of quantum tangling and de tangling that at some phase of transition leads to us. 😊 Entropy must be considered within the scope it’s relationship to quantum complexity. In short small scale fluctuations must run dry for the whole quantum baseline to reset into the potential of singulars expression. 😊

@randomwalk5095 11 ай бұрын

I completely agree with you. When I was young, I used to tell my mom that my room was never in disorder because disorder itself doesn't truly exist. Instead, what exists are infinite states of possible order, and none of them holds more inherent sense than another.

@methylene5 11 ай бұрын

If a workspace becomes disorganised, the ability to get work done rapidly approaches zero. So I would argue that certain states of possible order do make more inherent sense than others.

@lemurpotatoes7988 11 ай бұрын

If I understood Ramsey theory I could say something intelligent here.

@hyperduality2838 11 ай бұрын

@petermaunsell4575 11 ай бұрын

So your mother was the intervening force , if you keep your room tidy today as an adult it’s probably her victory, or your partners:)

@jumpycat 10 ай бұрын

Extremely organized workspace looks amazing, but it can intimide some people and drain creativity. On the other hand organizing is really good work hygiene after project is done.

@mishelleilieva9657 9 ай бұрын

You should read Asimov's story called "The last question". It covers the topic of entropy and this video explains perfectly the science behind it. The story also follows Sabrines idea about future life forms in higher entropy universe. It is one of my favorite Asimov's pieces.

@RobertR3750 6 ай бұрын

Asimov.

@mishelleilieva9657 6 ай бұрын

@@RobertR3750 oops, you're right. English is not native for me and we spell it with a "z".

@tezzerii 28 күн бұрын

I've read that. Very clever story ! I love Asimov.

@mishelleilieva9657 26 күн бұрын

@@tezzerii me, too! I think I read almost everything he wrote..

@audistik1199 23 күн бұрын

As a young boy I became a science fiction devotee, and Asimov was one if my favorites, among with Heinlein and Clarke. I presume you are 😊from an older generation like me to have these greats on your reading list. It was a seminal experience in my life.

@huynguyen4450 8 ай бұрын

Thanks Sabine! This makes me appreciate my current stat mech class more!

@SeattleShelby 10 ай бұрын

Sabine’s Carnot efficiency at explaining this stuff is 100%.

@redandblue1013 10 ай бұрын

So there is an infinite temperature gradient across her body?

@saraawwad9163 9 ай бұрын

Not possible 😂

@nancymatro8029 9 ай бұрын

Are you claiming to have Carnot knowledge of Sabine?

@msimon6808 9 ай бұрын

There are always losses. Superconductors radiate when the current flow changes.

@IsoMorphix 9 ай бұрын

@@nancymatro8029I appreciate this joke.

@suomeaboo 10 ай бұрын

9:55 Finally someone said it! I always considered a homogeneous mixture as "ordered", contrary to how lots of entropy explainers describe it as "disordered". This led me to lots of confusion over the years, until my recent physics classes cleared things up.

@cameronbartlett6593 10 ай бұрын

now run outside and play

@b1ff 10 ай бұрын

@cameronbartlett6593 no u

@limitlessenergy369 9 ай бұрын

EZ water / exclusion zone worth a read

@limitlessenergy369 9 ай бұрын

@@cameronbartlett6593I am a plasma engineer and I would beat you in physical anything best of 3, pick your best sport it wont matter even if I have never done it you will still lose because I will also pick my best sport and third party picks the third sport meaning you have low chances of winning. Go say your bs to yourself in the mirror. Not every nerd minded dude isn’t physically able.

@yazmeliayzol624 9 ай бұрын

Boy oh boy... I love checking comments and only seeing 2 of the supposed 4 comments left before me... it tells me I've really done my job well and been blocked by someone who is closed minded... I only see a comment from Cameron and darkside... But yup... I've said it for years the chaos and order are entirely indistinguishable in their ultimate forms... you are 100% right in saying homogeny is perfect order... it is also perfect chaos as no one part is distinguishable from the whole...

@LiamCraft02 9 ай бұрын

This is the best explanation of entropy I’ve heard yet

@anthonybelz7398 2 ай бұрын

One of the best commentaries on Entropy I've encountered thanks SB, especially as "The # of microstates per macrostate" - Given that a macrostate is simply an arbitrary human classification/aggregation, does this mean that entropy is an arbitrary physical aggregate outcome? I think I'm missing something, so I'll listen to your commentary until I can discern this thing. 🥝🐐

@geoicons1943 10 ай бұрын

LOL “I’d be inconvenient if you entered room and all the air went into a corner” @sabine you totally cracked me up with this joke. Thank you!

@exciton007 11 ай бұрын

Intuitive explanation of entropy. Thanks a lot

@charlesthomas8450 Ай бұрын

She’s an excellent teacher and her dry humor is hilarious! Love her!

@undercoveragent9889 23 күн бұрын

"She’s an excellent -teacher- _propagandist_ and her dry humor is hilarious! Love her!" FYP!

@mikey1836 4 ай бұрын

I’m not old, I’m just high entropy.

@marknovak6498 11 ай бұрын

This is the coolest clearest and most concise explanation of entropy ever. I wish my physics professors had taught it this way. It would have saved me so much sleep.

@aggies11 11 ай бұрын

True say. While almost anyone can understand a concept/subject, it really takes a special mind to be able to explain it in a way that can be understood by someone else. Sabine's way of conveying information is so refreshing.

@aurelienyonrac 11 ай бұрын

Yes. Finaly someone that admit it is a human bias and not a law.😅 To compare is not fair. Everyting is perfect compared to itself

@FGBFGB-vt7tc 11 ай бұрын

@@aggies11 I am a firm believer in the Feynman methodology: start as simple as you can to build up knowledge. If you can explain a complex idea in such a way that a child (or a non-specialist) can understand it while still being faithful to the core concepts then you are good!

@ricktownend9144 11 ай бұрын

@@aurelienyonrac Yes, I get fed up with it being called a law ... to call it an assumption, or - as sabine does - a matter of probability, would be much more accurate and satisfying.

@monnoo8221 11 ай бұрын

maybe, but she misses the point. and hence your professor too

@jeffb3357 10 ай бұрын

The entropy of KZfaq must have decreased since veritasium and Sabine both posted videos on entropy within two weeks of eachother :) They're both great, but Sabine definitely lives up to her motto of no gobbledygook... thanks Sabine!

@geoffwales8646 10 ай бұрын

Veritasium explains it better for the layperson, IMO.

@michalgric 10 ай бұрын

This video about life and entropy kzfaq.info/get/bejne/oZOmoJaLvNSxh58.html is really good match to these two videos you mentioned.

@siddified 10 ай бұрын

I like my gobbledygook with a good glass of razzmatazz

@AnthonyCassidy50 10 ай бұрын

I agree, they are both great. Sabine's was posted on Jun18, and Veritassium's on Jun2nd . So we know Sabine wasn't responding to his (since she was first) and since Veritassium takes longer than two weeks to make one of his elaborate videos, we know he started his before he knew Sabine was doing one. That's perfect. Also cool how they both didn't like the word "disorder" as entropy,, Veritassium likes entropy as "energy spread out", and Sabine presents her own argument.

@andrewmycock2203 10 ай бұрын

@@geoffwales8646not nit picking, correcting. 👍🏻

@fouriexwelldoom6813 2 күн бұрын

Du erklärst so unglaublich gut und strukturiert, dass ich es mir sogar auf englisch anhöre. Schön dass du dich mit all diesen Fragen auseinandersetzt und sie beantwortest und das bis ins Detail. Nur so nebenbei auch in den Physikbüchern an der Uni steht das nicht so genau z.B. Greiner usw. Kannst du auch etwas auf Deutsch machen?

@EminezArtus 2 ай бұрын

Probably one of the best explanation of Entropy. Thanks for the video.

@juancarlos-cl7cs 11 ай бұрын

Me encanta la profundidad y claridad que tienes, este tipo de contenidos es oro. Yo estudié Física y Filosofía y una conversación contigo me hubiera ahorrado años de dudas y confusiones. Gracias por esto.

@live_free_or_perish 11 ай бұрын

Thank you for delivering such great content 👏 always interesting, humorous, and informative. My field is engineering, but sometimes, I regret not pursuing physics. Watching your videos gives me a chance to see what I missed.

@SabineHossenfelder 11 ай бұрын

Many thanks from the entire team!

@barnsisback8524 11 ай бұрын

@@SabineHossenfelder Time does not pass, only you is moving thru the Time. Time is a coordinate of the state of the moving entropy. From the pass state to the present state you can aim the future state.

@enk335 11 ай бұрын

you still have time!

@effectingcause5484 11 ай бұрын

Engineering is good experience for a prospective physicist. Nikola Tesla, perhaps the greatest engineer, was by extension, also one of the greatest physicists who ever lived, especially in the field of electromagnetism.

@hyperduality2838 11 ай бұрын

@Grantnatnian 5 ай бұрын

Thanks Sabine! A few years out of college and missing my p Chem courses, this brought back happy memories

@justicegear85 8 ай бұрын

I really like this video and it helps and enables a better understanding on physics.

@alexandretorres5087 11 ай бұрын

This remembers me of the book "A Choice of Catastrophes" by Isaac Asimov. He talks about how to survive heat death by exploiting low entropy fluctuations. The book was written in 1979.

@A_Stereotypical_Guy 11 ай бұрын

Ah good remembers

@bullpuppy7455 11 ай бұрын

@@A_Stereotypical_Guy gooder:)

@Syncrotron9001 11 ай бұрын

We wont make it anywhere near that long

@Syncrotron9001 11 ай бұрын

Tru vacum coming soon

@perendinatorian 11 ай бұрын

also in ''the last question''. yah boi was preoccupied with surviving heat death.

@Anaesify 11 ай бұрын

Sabine your work has changed the very way I view life and physics in a way that's nearly spiritual. I feel so lucky to be able to learn about the beauty of the universe and physics from you

@virgild88 6 ай бұрын

thank you for this wonderful video and for all the others. you have kindled an interest in physics in me.

@minifix 7 ай бұрын

Sabine is not only intelligent enough to master a complex subject, but also think in new ways about how the data should be interpreted. It absolutely blew my mind when you explained how macro systems are a relative concept, and not an absolute value that happens to match our anthropocentric view of the universe. Thank you.

@katebuckley4523 2 ай бұрын

I often think about how the anthropocentric view tends to divide ‘reality’ into separate things where there are none .. ie. a kind of fiction that perceives order v chaos, living v non-living, observer v observed etc.. ‘we’ seem to separate ourselves out along with everything else. My hunch is that the energetic solidity we feel in the body gives rise to the appearance of everything else as distinct and knowable.. a kind of ‘specialness’ that has something to do with the apparent body’s drive to conserve low entropy... what we call ‘me’ is only a kind of interpretation and nothing at all in reality.

@tyfooods 11 ай бұрын

The idea that there are always macrostates capable of turning a high entropy system into a low entropy system is fascinating. Entropy being constant, but perceived by us macrostates as variable, and thus subjective is powerful. I love how more and more physicists are adopting such a perspective! 😁✨

@adamt5 11 ай бұрын

time crystals are a great example. Check that out!

@thearpox7873 10 ай бұрын

It may be powerful, but that doesn't mean it is particularly useful. Saying that life may be able to emerge post-heat death of the universe just because it perceives reality differently may be a great Douglas Adams book, but belongs right alongside the parallel dimensions theories in plausibility.

@florianp4627 10 ай бұрын

@@thearpox7873isn't the idea similar to Penrose's cyclical cosmos hypothesis? And he has proposed some actual ways to experimentally verify that

@thearpox7873 10 ай бұрын

@@florianp4627 It depends on what you mean by "idea" and what you mean by "similar". But I personally find Penrose's hypothesis intellectually coherent, interesting and plausibly congruent with reality, while Sabine here is engaging in the exact same cognitive hocus-pocus that she makes fun of certain other physicists so much for.

@dzcav3 10 ай бұрын

Sounds like Maxwell's demon

@abelriboulot7166 11 ай бұрын

Great video! But tiny correction: high entropy means high information, not low information. The more random something is, the least it can be succinctly explained. At least for Shannon Entropy. For instance imagine water in its solid form with molecules neatly aligned, it can be described succinctly as a pattern repeating, whereas in its (high entropy) gaseous form, each particle can be anywhere in a the volume that contains it: describing the micro-states would require describing the position of each molecule (high information).

@commentarytalk1446 11 ай бұрын

That's a nice description - just watching the vid but based on what you say I wonder if this video can do better than that concise description. Maybe the simpler the explanation the more encompassing it is also? Entropy feels like such a description tending towards that... hence it's ubquity/applicability.

@willthecat3861 11 ай бұрын

Ya... I think one has to be careful when analyzing a physical example using Shannon. In physics it about information known (or information that can be potentially known.) It's not conceivable that we could know very much about the micro-states of gas molecules. Yet, we have a lot of information about the micro-states of ice. Thus... in the context of the ice and gas example you gave.... it's kind of opposite of what you said. There is a subtle connection between the two concepts of entropy. A good paper is by Jaynes, if you want to read that. Sean Carroll also writes about this too.

@lawrencedoliveiro9104 11 ай бұрын

But given that entropy tends to increase, does that mean the amount of information tends to increase or decrease? Consider the case of a gas confined to one half of a container by a barrier. Then the barrier is opened and the gas escapes to fill both halves of the container. Do we have more or less information about the positions of the gas particles than we did before?

@jarnorajala 11 ай бұрын

This bothered me too. Maybe Sabine meant information in the colloquial sense, not how it's defined in Information Theory. Either way it's confusing.

@noneofyourbusiness-qd7xi 11 ай бұрын

You are perfectly right and she got it wrong. Information and entropy are perfectly positively correlated, not negatively.

@4c00h 4 ай бұрын

13:37 this is key, thanks for all the clear explanations and happy to see you got ready early for movember

@EricBittner 9 ай бұрын

Very nice! It's refreshing to hear someone talk about Entropy in this manner. When I teach thermo, I always emphasize that Entropy is not about order or disorder. But, I don't know what those terms mean in a quantitative sense. Second, the analogy of the universe being in 1 microstate per microstate is spot-on correct. The thermodynamic definition of entropy dS = dq/T (for a reversible process) also ties into this analogy. If the universe's entropy increases, then heat (dq) must be added...but from where? That "where" can be incorporated into your definition of the universe, which moves the "where" to somewhere else, und so wieder/ So, one is faced with the notion that the universe expansion must be adiabatic (dS = 0)....which is a beautiful problem in Callen's Thermodynamics book.

@homeworld22 11 ай бұрын

For a mortal being with a life expectancy of ~80yrs I confess I spend an irrationally large portion of my life brooding on the eventual heat death of the universe. Glad to find videos like this on occasion which at least try and come up with a philosophical explanation for why we shouldn't feel depressed over the stars eventually going out. Kudos Sabine!

@edh.9584 11 ай бұрын

It almost makes one consider praying to God.

@siddified 11 ай бұрын

@@edh.9584 which one.. There's so many to choose from...

@jongyon7192p 11 ай бұрын

@siddified Definitely the Pasta One Although I personally like the machine god that came from the future

@edh.9584 10 ай бұрын

@@siddified Well, choose one.

@jongyon7192p 10 ай бұрын

@@edh.9584 The "satanic temple" has some surprisingly good doctrine

@wyrmh0le 10 ай бұрын

Very interesting point about 'macrostates' that I've never heard or thought of before. Definitely food for thought. Thanks!

@ArashKhayyamdar-pd3lr 6 күн бұрын

I enjoy watching your videos specially about subjects that I'm already familiar with.

@42_universe 2 ай бұрын

Finally a video makes the topic crystal clear. And the comments anout macro vs micro states was incredibly logical and very interesting. This should be the ultimate video on entropy.

@luipaardprint 11 ай бұрын

I've always read the term heat death as the death of heat, which made a lot of sense to me.

@SchgurmTewehr 11 ай бұрын

Or a death caused by heat. It could mean both things, and language is just inaccurate in many ways.

@AdaptiveApeHybrid 11 ай бұрын

I thought so too lol

@vikiai4241 11 ай бұрын

Yes, the word order in English defaults to "Death by heat" , but "Death of heat" is also a valid interpretation of the words, though not the default.

@gnomiefirst9201 11 ай бұрын

@@vikiai4241 that's interesting because I am a native English speaker and frequently come onto this but never was sure about my way of thinking about it. Thanks for the validation lol.

@FredMaverik 11 ай бұрын

@@vikiai4241 Why though? What rule is there

@scifieric 11 ай бұрын

"It can only go downhill from here" made me laugh out loud. Another excellent video that teaches us about science. Lovely.

@Donald-fg2ew Ай бұрын

For the life of me I don't remember where I first heard "life is the postponement of entropy" but that quote has stuck with me since I was about 15 or 16 years old so had been a factor in my thinking for over 30 years now. It is nice to see someone talk about life vs entropy.

@adrianwright8685 5 ай бұрын

Love the videos Sabine, especially the hand waving - are you trying to hypnotize us?

@ilkoderez601 11 ай бұрын

I love your channel Sabine. I've been following you for a long time (we even had an epic argument on Twitter _many_ years ago) and it makes me happy that your channel is doing good!

@matthewparker9276 11 ай бұрын

The statistical description of entropy has never resonated with me, but your talk about other life with access to different macrostates is very interesting, and warrants further thought.

@kristianshreiner6893 11 ай бұрын

It’s vague and non substantial. She needs to produce some scenario that could meaningfully demonstrate how one side steps Boltzmann’s formulation of the second law. Not the order/ disorder pop science stuff, the physics. Proposing some race of hypothetical beings that rely on different Marco states is about as meaningful as proposing that magical beings will eventually come into existence who live differently. I love her, but this argument isn’t serious.

@demonicakane2083 11 ай бұрын

I didn't get wut she means by Complex systems with different microstates which we can't use and further the entropy is small for them.... Can u explain

@ywtcc 11 ай бұрын

Could Entropy just be a matter of perspective? If a horizon from one perspective can appear to be a singularity from another perspective... A horizon takes an eternity, and a singularity happens in an instant.... And, a horizon is a state of maximum entropy, and a singularity is a state of minimum entropy... Entropy should be dependent on your reference frame. If your horizon is growing, then your entropy should be growing. I've been thinking about it like this after listening to Leonard Susskind. I don't know if I'm getting it quite right, but it's really interesting to think about in this way.

@ThePowerLover 11 ай бұрын

@@kristianshreiner6893 _"Proposing some race of hypothetical beings that rely on different Marco states is about as meaningful as proposing that magical beings will eventually come into existence who live differently."_ Well, if you understand "magic" as "fairy tales", like many, then its a straw man fallacy, because Sabine didn't thought of that on terms of "something that doesn't exist nor can exist". And she didn't use the order/disorder stuff, but to only criticize it. Boltzmann's formulation, as Sabine hinted on this video, it's only useful for thinks that we "know", not stuff we clearly don't know, as information not accesible to us. Stop lying pls.

@ThePowerLover 11 ай бұрын

@@ywtcc All stadistic is clearly a "matter of perspective"-

@mechez774 7 ай бұрын

I recently learned that Planck was highly motivated by believing in the 2nd law, but was still reluctant to embrace atomism. What I seem to remember from either a P Chem or a Chem E course that entropy, or was it enthalpy(?), is a calculable quantity that plays a role in the equations much the same as energy. We can recognize that it is a construct, but it still plays a role in our modern frame of reference. I think it is something still worth pondering as Planck did so I thank you for the video , although the first 8 minutes of textbook regurgitation make me want to pound my head on the desk. Actually I dont own a desk, just a sewing machine table so I can make my sails and escape to my ocean sabbatical,,, maybe then I will understand entropy

@pascalneraudeau2084 42 минут бұрын

Excellent ! ... personally I even think that there are two types of entropy: thermal which tends to increase (be diluted) AND material which tends to decrease (become organized)

@Dron008 11 ай бұрын

I have been trying to understand entropy for decades, now I am a little closer to it.

@treadwell1917 10 ай бұрын

Entropy is simply a lack of data. In a “real” sense though. Information or data is better to say than order because things being “ordered” are subjective. So entropy happens when you begin to lose information of a system. If something is breaking down it’s order or information is also separating. Therefore it’s entropy is increasing. In a way entropy could be seen as time. Because time moves forward as things spread out or break down. It’s even how we quantify the “second” is by using the measure of an atom breaking down. These two things are the same though. We measure time by our perception of all systems around us progressing towards entropy. So time moves based on the frame rate we perceive it which is again measured or quantized by entropy.

@treadwell1917 10 ай бұрын

I wasn’t far along enough in the video she pretty much says the same thing.

@cinegraphics 10 ай бұрын

Entropy is simply the rise of equality. Which is a result of calculations the nature does to produce the next moment of time. So, entropy is simply the result of calculation. It's real, but it's wrongly defined. Entropy is not a measure of disorder. It's a measure of equality. Because once the full equality is reached, the universe stops. The formulas still work, but their inputs and outputs become the same, hence there's no change, hence the passage of time makes no difference. That's maximum entropy. Or equality. So, equality is bad 😊

@snaawflake 10 ай бұрын

@@cinegraphics No their inputs and outputs don't become the same, only when you're working with an information discarding model of the universe (macrostate). There is still exactly one microstate leading to exactly one next microstate, and thus each microstate has exactly one preceding microstate, so the universe in terms of microstates cannot advance to a point where the inputs and outputs become the same; as then that final microstate that would be reached would have more than one way for it to be reached: first the last state of the universe in which inputs and outputs were not the same, and second the final state itself where inputs and outputs are the same. But this is in contradiction with the assumption that there is only exactly one microstate leading to exactly one next microstate.

@cinegraphics 10 ай бұрын

@@snaawflake you're forgetting the rounding errors. At one moment the error level drops below the computation precision and the output becomes same as input. And that's the end of computation. Death of the universe. Stable state has been reached.

@willdon.1279 11 ай бұрын

She is wonderful at explaining very difficult or (almost) impossible ideas in an understandable way. Alas, even Sabine leaves my poor brain often mystified, but always stretched, curious, and entertained. 🙂

@hannahbaxter8825 11 ай бұрын

Same same

@warrenjoseph76 11 ай бұрын

When it’s a topic like this I need to watch a few times over a few days and dig more into some of the ideas with other videos. I like that she doesn’t completely dumb it down for people like us but opens the door for us to learn more (such as that entropy logarithm formula). But yeah at the end of this video I STILL don’t QUITE understand a simple way to explain entropy to someone. Yet. But I will after a few views 😂

@aaronreyes7645 11 ай бұрын

She is wonderful Without the gobblety gook

@jackcarswell4515 10 ай бұрын

@@aaronreyes7645 In my opinion, it was all gobblety gook. She talked in circles and never really said anything at all

@TheBsavage 10 ай бұрын

I know, right? I'm totally in love with her. With her MIND, but I suspect it's a package deal. I'm still game.

@vieiradelimafilho 2 ай бұрын

Great video, as usual. Sabine really puts things in perspective with her very humble scientific admission of gaps. Around the 7th minute we can visualize clearly what is the greatest bias (blindness?) that will make our grandkids cringe in a century: "how could you not understand this emergent order?" To me it feels like it's way past time we start conceptualizing things like "syntropy" and eutropy", and take Metaphysics seriously again. Restore it to its natural place since Aristotle: the real "theory of everything". Intuition (idealism) is the way we understand things so that science can make strides again. Empricism depends on it, and is basically a secondary development.

@ColonelFredPuntridge 9 ай бұрын

If anyone here has NOT read Isaac Asimov's short-story "The Last Question", now would be a good time.

@Rotaermel Ай бұрын

Also, „Exhalation“ by Ted Chiang.

@Viewpoint314 11 ай бұрын

That was one of the best lectures although it is hard to compare lectures. It's maybe the first time entropy makes sense even though I have been reading about it all my life. I also like your dry physics humor. One needs humor in life. So thank you very much.

@inciaradible7144 10 ай бұрын

Fascinating video and very well explained; entropy has always been one of these quantities I've found difficult to define or understand. It has mostly been explained to me in the concept of order (or just plain equations), and those mostly just made me go ‘oh that makes sense... wait.’ Minor note, Boltzmann has two n's. 😅

@GetMoGaming 9 ай бұрын

_"Not enough data for a meaningful answer."_

@mikolavision 7 ай бұрын

I LOVE YOUR INCREDIBLE MIND! NEVER able to find ANYBODY who GETS IT !! Please be forever blessed miki

@KauTi0N 11 ай бұрын

I've been waiting a long time for this video. Sabine, you are an amazing communicator and I think the world needs to hear you. This channel and other sources like it are THE REASON I use the internet. Thank you! ❤

@hyperduality2838 11 ай бұрын

@JohnPretty1 11 ай бұрын

You are psychic?!

@gregwarrener4848 11 ай бұрын

@@hyperduality2838 sounds like your grasping for straws, likely for some sort of affirmation of a biased narrative. entropy is all around you and can be observed, posing a balance to the force is wishful thinking

@hyperduality2838 11 ай бұрын

@@gregwarrener4848 Your concept of reality is a prediction or model -- syntropic!

@MR-ub6sq 11 ай бұрын

@@hyperduality2838 Really?

@adanbrown 10 ай бұрын

Videos that provide a "simple understanding" of historically complex concepts (like the laws of thermodynamics) are crucial for our kids to hear and learn. I am especially interested when the video explains what we "don't know" or "don't yet understand" to pique their interest in what to solve next!

@joeharker7918 4 ай бұрын

Wow, this is so far above my head it’s funny. But it is amazing to hear this kind of analysis done by someone so educated. I agree with the concept of entropy not being the opposite of order. That never sat right with me, either. Love your work! ❤

@francisbosse3702 5 ай бұрын

Great and simple as usual😊

@cedriclorand1634 11 ай бұрын

Sabine s humour and wit is so empowering. Such a wonderful person. Thank you for existing Sabine 😂

@leonardgibney2997 11 ай бұрын

She doesn't exist. Our reality is an illusion.

@hyperduality2838 11 ай бұрын

@peter9477 11 ай бұрын

She couldn't help it. Her existence is a high entropy state.

@johnkufeldt3564 11 ай бұрын

I agree, but you summed it upwith far fewer words. Cheers from Canada.

@neanda 11 ай бұрын

so true 🤣 it's so subtle as it blends in with her education. imagine her being the teacher, she would grab your attention because you'd be like wtf? then listen more. she's a great teacher. 'if you tell this to a random physicist on the street to see if they agree, you should let them go as they've got better things to do' 🤣

@gaemlinsidoharthi 11 ай бұрын

This reminds me of Roger Penrose’s ideas. I think you shared a stage with him at one point. If we change our scale of looking at the universe, in both space *and* time, the almost uniform distribution after 10^100 years (or whatever the number is) becomes recognisably clumpy again. The almost imperceptible effects of gravity speed up and become perceptible again.

@CodepageNet 11 ай бұрын

i don't think this is possible. if the universe at that point is nothing but a diluteted, even, gas, there may happen some random "clumping" but there just not enough matter nearby for anything more than a few particles hooking up.

@akidnag 11 ай бұрын

The most probable state for the universe is a gigantic black hole, which has the largest entropy given by the Bekenstein formula.

@IamPreacherMan 11 ай бұрын

@@CodepageNet cold things contract. The universe is expanding because it’s still heating as evidenced by the high number of stars currently burning. Turn the heat off and the dark matter contracts as does the distance between all particles and celestial bodies. The crunch will happen as it obviously happened before. Unless you believe the universe poofed into existed out of nothing. Which defies all known physics and logic. I think Penrose is brilliant. And wrong about his cyclical universe approach. But I also think hawking was wrong about BH radiation for a number of reasons.

@5naxalotl 11 ай бұрын

@@CodepageNet the point is that there is eventually no matter, just stray photons. but photons move at the speed of light and from their point of view everything happens instantly. penrose claims that this has peculiar consequences. i can't tell you more than that, or vouch for penrose, but you don't seem to be anticipating the situation fully

@wafikiri_ 11 ай бұрын

Once every remaining particle is beyond the event horizon of every other particle, there is no way they can interact again. Expansion of the universe would end up in a zillion one-particle universes.

@LordBones.Cascadia 9 ай бұрын

😂 Much credit given to your intellectual sense of humour. Great work on the presentation, Sabine! 🎉 😂

@fabzy4L 4 ай бұрын

Ive been trying to explain this to students for years, this video is spot on 🤝🏻

@vazap8662 11 ай бұрын

Sabine has just addressed a question I been tickling me since my teenage years. This notion of pockets of emergent decreasing of entropy, such as say, our brains. I'm so grateful to hear her address this topic.

@FredMaverik 11 ай бұрын

...what

@hyperduality2838 11 ай бұрын

@henrythegreatamerican8136 11 ай бұрын

Locally you can have decreasing entropy, but the overall entire system remains highly entropic.

@Lightning_Lance 11 ай бұрын

@@hyperduality2838 I'm here to remind you to take your pills.

@tnb178 11 ай бұрын

The analogy of "disorder" can work in the right context. You could say: there's all kinds of messy but only one kind of clean. For that reason your room tends towards getting messy if you make any change not specifically targetting cleanliness. What I like about the example is that it uses the cleanliness as a macroscopic state defined by a human and talks about the associated microstate count.

@boldCactuslad 11 ай бұрын

i see you've never been to a certain college dorm. as determined with mathematical certainty, this was a space of superlative messiness: the Platonic form of disorder, chaos so intense both the gravitational and nuclear forces had all but given up - trash and antitrash not belonging to our dimensions materialized, ionized, annihilated, sublimated, vaporized, crystallized, and floated about the space with such frequency that any external modification to the region did nudge the system towards cleanliness regardless of the actor's intention. the situation passed when a window broke itself in its frustration. the resulting decompression vented the contents of the room (including furniture, wallpaper, rodentia) into the environment.

@petevenuti7355 11 ай бұрын

A single homogeneous pile of ash should be the cleanest state, if it's totally homogeneous then there truly can be only one state..

@off6848 11 ай бұрын

@@petevenuti7355 This is correct and similar to what I was going to say about her comment that "entropy is why things break down" Actually things break apart because usually a "thing" is comprised of many things forced together and eventually unravel because they don't share the same essence. A house will break down because its a collection of wood, glue, sand, gypsum, wire, metal etc.. But those things on their own do not break down

@LMarti13 11 ай бұрын

except that there isn't one kind of clean, there are literally an infinite number of them

@wojtek4p4 11 ай бұрын

@@LMarti13 If you assume any margin where two adjacent states would be considered "the same" there's a finite amount of states - both "clean" and "dirty". E.g. if you assume that a pair of scissors being moved by less than 1mm constitutes the same state (that is: you quantize the position) the amount of states becomes finite. Importantly increasing the "precision" doesn't make the amount of states infinite - and it doesn't change the proportion of "clean" and "dirty" states significantly. So even at a limit of however small your measurement error is, the amount of "clean" states is smaller than the amount of "dirty" status. Unless quantum effects start taking over, the amount of "clean" states is lower than the amount of dirty "states", no matter the scale.

@tomjohnson5134 4 күн бұрын

Most discussions involving entropy are primarily philosophical, but there is a simple, easy explanation of entropy: in any thermodynamic process, heat is the integral of TdS where T is absolute temperature and S is entropy. The simple act of looking at a process on a graph of T versus S gives you a quick estimate of how much heat is exchanged during that process: a good example is the Mollier Diagram which makes child's play of power cycles. Accordingly, entropy's most practical definition is simply as a measure of much heat energy is contained by a substance at any temperature. Now, this ties to the 2nd Law of Thermodynamics via one other simple equation, the "Clausius Inequality" which states that every thermodynamic cycle results in either zero change in entropy, or a positive change in entropy.

@martinzumstein351 6 ай бұрын

Very nice and easy explanation.

@PaulElmont-fd1xc 11 ай бұрын

I have had major depressive episodes because of entropy and the second law. I am deadly serious. Since learning about it in high school physics class, I have always considered it to be my greatest fear. Thank you for easing my fear a bit. 😊

@SabineHossenfelder 11 ай бұрын

I totally know what you mean.

@MommysGoodPuppy 11 ай бұрын

I like to think life only came about because of entropy because a human that builds a car will generate a lot more entropy than a rock that gets chipped to pieces over time.

@joansparky4439 11 ай бұрын

If you like SciFi I can suggest a book to you that has this as part of the story.. it's called 'Voyage from Yesteryear' by James P Hogan. Should give you a positive story to carry around wherever you go.

@jackkrell4238 11 ай бұрын

@@joansparky4439 What about the concept of entropy daunts you so much?

@MommysGoodPuppy 11 ай бұрын

@@PaulElmont-fd1xc also an uplifting story on entropy is "The Last Question" by Isaac Asimov

@nissieln 11 ай бұрын

This is truly your best video IMO. Thank you Sabine! Finally a happy ending, from which, as you said, everything will have to go downhill 😂

@user-ut4vl8bw2k 9 ай бұрын

1:45 if equations work both ways in time, can we can exclude time from equasion for good? Maybe they work in both directions because time is not a thing itself, but an abstract measure of relative movement.

@danielsneighborhood2050 6 күн бұрын

The air always moves to the side when I enter the room.

@JoeyBlogs007 10 ай бұрын

13:16 But does information really effect the state of anything? Just because we don't have information surely has no bearing on entropy whatsoever. Surely entropy is independent of information. It's just a variable state of things or of matter. It's said that information entropy is a separate concept from thermodynamic entropy, even though they share the same name.

@JoeyBlogs007 10 ай бұрын

While information about a system can influence our ability to describe or predict its state, it does not directly alter the inherent thermodynamic entropy of the system. The entropy of a closed system will tend to increase or remain constant over time, regardless of the amount or quality of information we possess about that system.

@PATRIK67KALLBACK 11 ай бұрын

Great video Sabine! Even if I have a MSc in chemistry and PhD in pharmacy, one of the hardest thing to undetstand is the thermodynamics. You really have to eat and breathe thermodynamics to really understand it, and it doesn't come with intuition, and one of these things are entropy. So thank you Sabine to make these entropy more intuitiv.

@mixerD1- 11 ай бұрын

Farmacy? Do you mean agriculture or is this alternative medicine? Sorry... couldn't help myself.😁

@andrewmycock2203 11 ай бұрын

@@mixerD1-or maybe an Fhd.

@PATRIK67KALLBACK 11 ай бұрын

@@mixerD1-ha ha, too much swedish 😊

@noneofyourbusiness-qd7xi 11 ай бұрын

Your physical chemistry profs will be extremely disappointed if they read your comment (and likely be sorry that they let you pass)

@stevenhopper-hj5uh 2 ай бұрын

Sabine: Thanks very much for your program! Regarding entropy, is expansion of the universe reducing it? Will gravity, bring mass back together, in an energy releasing, lowering of entropy? Is entropy in the "universe" constant, the way mass-energy is conserved?

@irenerosenberg3609 5 ай бұрын

So glad a brilliant person, such as Sabine, was also confused by the use of "order" to describe entropy. "Order" never made sense to me in relation to entropy.

@ahmedtoufahi5198 11 ай бұрын

I guess Sabine is the best person that has ever explained this relationship between order, life, entropy and those things without either being carried away in theory or relying on very superficial metaphors. Because maybe physics is both ! intuition and somewhat philosiphical insights + rigourous mathematical modals.

@No-cg9kj 11 ай бұрын

Physics isn't philosophy, it's what we know to be reality.

@off6848 11 ай бұрын

@@No-cg9kj What you think you know (episteme) is philosophy.

@ThePowerLover 11 ай бұрын

@@No-cg9kj Physics is not that despite its name.

@ahmedtoufahi5198 11 ай бұрын

@@No-cg9kj I agree with you actually. Philosophical thinking doesnt mean something detached from reality. There s a section in philospohy about science and modelization and those things. I mean that it's useful to take some time to pose some "meta" questions about what we're trying to look for in nature, what is really fundemantal and what stems from our specific human view of nature. In this video Sabine took sometime to think that maybe our defintion of entropy is a reflexion of what information is accessible to US and what energy WE can use. It is pretty philosophical it seems to me. It's funny how your user name is NO btw xd, thnx for ur comment.

@shrub4248 11 ай бұрын

Science is built up on a bedrock of epistemology.

@user-hj8uo1zl6k 2 ай бұрын

I liked this video because it resonated with my views on entropy that I gained after reading the inspiring article by Myron Tribus and Edward C. McIrvine, "Energy and Information", Scientific American , Vol. 225, No. 3 (September 1971), pp. 179-190. I strongly recommend that paper, because it provides an insightful complement and an additional explanation and formalization of the points raised by Sabine. Following Shannon's original proposal, lucidly explained by Tribus and NcIrvine, entropy is defined as the degree of uncertainty, X, that one has about a certain question Q. A question can be "In which part of the box is the particle, left or right?" . Complete uncertainty about that question means that there is equal probability, p_1= p_2 = 1/2, for the particle being in the left or the right part of the box. The entropy, defined as S(Q|X)= - \sum p_i ln p_i, is then S(Q|X)= - ln (1/2) = ln 2. On the contrary, if one knows the answer, namely that the particle is in the left part (denoted 1) and not in the right part (denoted 2), then p_1=1 and p_2=0. The entropy is then S(Q|X) = 0, which means that there is no uncertainty about the question Q. This is in contrast with S(Q|X) = ln 2, which is the maximal ignorance about the question Q. The authors then remark: "The only state of greater ignorance is not to know Q." And not knowing Q, or even worse, not even be aware of the fact that one must bring Q into the definition of entropy, is a source of all the confusion and all the difficulties people have in understanding the concept of entropy. It was great that Sabine revealed in her own wonderful and easily grasping way this important point to the general public. In the article, cited above, the simple model with two possible answers that I gave to illustrate the idea, was generalized to the cases of generic questions and any number of possible answers. Information was defined as the difference between two uncertainties, I= S(Q|X) - S(Q|X'), The relation to the thermodynamic entropy was exposed. Again, a fabulous, inspiring, highly cited paper that removes the longstanding "mystery" and confusion.

@kaboomboom5967 2 ай бұрын

I dont understand but i agree 😁

@user-hj8uo1zl6k 2 ай бұрын

@@kaboomboom5967 You would certainly understand the Scientific American paper "Energy and Information" which is very clear and readable, written for general audience.

@christofchaos 8 ай бұрын

Lots of mistakes to address here so I’ll just start with Heat death and why it will happen. In your box example you said particles on one side of the box and particles allowed to flow through the whole box have the same micro state. This isn’t necessarily true, but is built on a naive definition of micro state and a naive interpretation of particulate motion. For one, the particles in the right side of the box are moving with a specific average velocity within a specific volume. If those particles are then free to love in a larger volume, their average velocity decreases, increasing entropy. The two micro states are not the same, as their volumes differ. If we apply this reasoning to you “reservoir” analogy (I really like that analogy), we find that the volume of space occupied by light is smallest near a reservoir (this is due to both angle of incidence and gravity, as gravity stretches space near a star, causing a lensing effect). Further out, the light dissipates energy by transferring heat to particles and loses volume due to cutting a greater angle through space and reduces lensing as it moves away from the strong gravitational pull of the star. At some point in the distant future, the size and number of reservoirs will be too small for the energy of light per volume of space to spontaneously generate virtual particle pairs. Beyond that, the EM field will vibrate at too weak a resonance to generate large enough motion in particles it interacts with, thereby making particle collisions less likely and temperature to drop. This is the heat death.

@whyofpsi 11 ай бұрын

I like how complexity emerges somewhere between minimum and maximum entropy :)

@anywallsocket 11 ай бұрын

Indeed, it is within the inflection point of rate change that new minima can be added.

@serpentphoenix 11 ай бұрын

"If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations-then so much the worse for Maxwell’s equations. If it is found to be contradicted by observation-well these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation." - Arthur Eddington, New Pathways in Science

@cdmarshall7448 7 ай бұрын

A physicist educated in thermodynamics would never call all energy heat. All heat is energy but not all energy equates to thermodynamic heat. “Much of thermodynamics deals with three closely related concepts: temperature, energy, and heat. Much of students’ difficulty with thermodynamics comes from confusing these three concepts with each other.” -D. V. Schroeder, Thermal Physics, Addison Wesley Longman, 2000

@skriptzurvorlesung4474 6 ай бұрын

Can you explain, why sunlight is low in entropy but for example the radiation of a woodstove is high in entropy?

@zerocero5850 11 ай бұрын

So much food for thought. One of your best yet Sabine.

@hyperduality2838 11 ай бұрын

@dr.gordontaub1702 11 ай бұрын

I think many of my (undergraduate) students would get a laugh (or a cry) out of the phrase, '...You don't need to know that much maths, just differential equations and probabilities...'

@bryck7853 11 ай бұрын

linear algebra and complex number theory be damned!

@afterthesmash 11 ай бұрын

There's not a single thing about Special Relativity that Einstein couldn't have explained to Archimedes. Einstein would probably take a detour into explaining the modern notation of algebra. But this wouldn't really _be_ algebra, for the same reason that many undergraduates in computer science can barely distinguish a formula from an equation. Archimedes: This algebra thing is cool! I wonder what else you can do with it. Einstein: Well, I did once take a year-long detour into the deep technical weeds of Ricci tensors. Archimedes: Excellent! Please explain. [Archimedes smooths out some complex geometric diagram in the sand.] Einstein: Uh, okay, but we're going to need a _much_ bigger beach.

@johnzander9990 11 ай бұрын

My college students would laugh at "half the box being filled with particles" as being a low entropy state as they would understand that this is just one state that's counted in the entropy of the system. As a person that implies you have physics students, do you not see anything wrong with her understanding of thermodynamics?

@brooklyna007 11 ай бұрын

@@johnzander9990 But it is clearly lower relative entropy to being fully spread out in the box. Just by halving the space you're halving the number of microstates. Further, it is clearly not an equilibrium state and not a state that can last long.

@brooklyna007 11 ай бұрын

@@johnzander9990 Sorry, I should add that your understanding of entropy is a bit concerning. The state of the box half filled is the macrostate. It is not one of the contributing microstates to some other macrostate as your statement implies. Ex. You could instead have the microstate be that all molecules are in the box and *then* you could consider all on one side as a contributing microstate to that macrostate.

@kazimierzmarkiel5400 9 ай бұрын

On diagram ( 7.22 min) of the Space expansion there is no noted when ( on time axis) the black holes started the work of mass absorption behind the event horizon. It should be generally after forming the stars and galaxies. This space cleaners activity can be related with Space expansion here and now. Stary

@andreastell3959 8 ай бұрын

Thanks Sabine. I've been thinking (and teaching) a very similar approach to entropy for a while now. However, I do disagree with your assertion that we choose the macrostates in all cases. In (approximate) thermal equilibrium, the macroscopic state description is emergent and becomes an actual physical quantity. In such a situation, the coarse graining employed by the 2nd law of thermodynamics is practically inevitable and not subject to choice. But I fully agree that such an argument does not fit the entire universe. I'd love to hear your take on the corresponding quantum formulation using mixed states and tracing over tensor factor spaces, because I have some severe issues with it!

@calebgoodfellowcg 11 ай бұрын

This is my favorite video you’ve ever done. I’ve been arguing something similar for probably a year now, although without the same knowledge base you have. I tend to take this increasing entropy level as a symptom of the universe increasing in complexity. And with each collapse of a complex system due to entropy, that old macrostate is still more complex than it was before the rising entropy made it more complex. Rinse and repeat and the universe begins to evolve to its current state. Keep at the great videos!

@CharlesWestinghIII 11 ай бұрын

Well no. If all elementary particles are evenly distributed in the entire universe there will be no complexity. Then there will not be any low entropy states to draw complexity from like the sun or other sources of energy. This is what I thought to be the classical interpretation of heat death but I may be wrong and unfortunately this is where I lost Sabine in her reasoning. The leap from the arrow of time entropy to that high entropy but yet complex universe was a little too large for me to follow…

@grayaj23 11 ай бұрын

@@CharlesWestinghIII See, I thought "complexity" was the amount of information you needed in order to describe a system. So generally, complexity would increase WITH entropy. An ordered system is easier to describe. I don't follow Sabine's point at the end, though. Future beings may have more effective strategies for exploiting such low entropy states as may exist, and the concept may be relative based on one's starting information. But low entropy states are going to continue to be harder to find, I'd think. I'm not a physicist, though, so I'm prepared to be completely wrong about this.

@noneofyourbusiness-qd7xi 11 ай бұрын

There is no correlation between complexity and entropy. Actually on a global level increasing entropy leads to less complexity, as complex structures have a lower entropy, than uniformly distributed particles. Overall increasing entropy doesn't rule out locally decreasing entropy (leading to complex systems like us), but generally/for the closed system: higher entropy -> complexity decreases, uniform distribution increases. Note: complexity != information. The informational content of a closed system indeed increases with the entropy of that system. Further: you can not exploit low entropic states. You can only exploit energy sources which may allow you to locally reduce the entropy (will still increasing the entropy of the overall, closed system). That's why we exist. Unfortunately there are physical limits to how efficient an energy source can be exploited.

@crawkn 11 ай бұрын

We don't age because of entropy increase. Entropy increase applies always, from the time of conception, and being alive is largely the process of investing energy to combat entropy. We age because our genome is pre-programmed with our life-cycle. There are species survival advantages to short life-spans, that's why.

@raffaeledivora9517 11 ай бұрын

Technically we still do, since we age because the entropy-combacting machinery in our body slowly wears and breaks down

@crawkn 11 ай бұрын

@@raffaeledivora9517 it wears and breaks down because of genetic features, which just stop required maintenance from occuring. There is nothing in theory to prevent the same maintenance as occurs in our 20's from continuing indefinitely. It doesn't because it's not designed to.

@gdclemo 11 ай бұрын

@@crawkn that maintenance is just something that fights against the natural process of aging though. You could say that aging is the expected outcome, but our bodies have mechanisms to counteract it for long enough for us to reproduce. Then, once those mechanisms stop, entropy takes over.

@noneofyourbusiness-qd7xi 11 ай бұрын

@@raffaeledivora9517 crawkn is perfectly right. Aging is a problem of the "architecture" of the eukaryotic genome. If it would be an issue of cell structures breaking down over time, then life would have long ceased to exist on earth, as every reproducing cell is in direct lineage from its earliest predecessors some 3.8b (for possible 4.1b) years ago. Aging is the result of a genome has not been pushed by evolution towards longevity. That's all. Just ask a few Hela cells, if they feel aging is a real problem for them.

@crawkn 11 ай бұрын

@@gdclemo yes and the stop of maintenance is programmed. Probably the wealthy will soon have access to genetic modifications to change the programming, and live much longer. The alterations will be far more efficient and safer if done at the conception stage.