The mind-bending physics of time | Sean Carroll

[@bigthink]

Watch our full interview, "The Universe in 90 Minutes," with Sean Carroll: kzbin.info/www/bejne/qn6XpH-jqZaIn5o

[@jokrg]

Pretty cool stuff! I like the direction this idea was taken in the “Rise Of The Moments” books by Carl L. Gabriel.

[@educatedguest1510]

"Theory is when everything is known, but nothing works. Practice is when everything works, but no one knows why. We combine theory and practice: nothing works and no one knows why!" Albert Einstein Sean Carroll have not read "Time Matters eBook".

[@rafars2246]

We make up time in our heads to make sense of things we do every day, but time doesn't exist.

[@alexgoslar4057]

There is a symbiotic relationship between consumerism and industrialization. But clean energy and green transition are not intrinsic parts of this equation because reversing the climate digression does not generate income. One way of integrating environmental issues is by considering the climate as a commodity that has its own fungible and tradable value. And convincing customers that the most desirable commodity is the climate and that climate currency supersedes the value of any other commodity.

[@davidharrison8975]

Time isn't anything more than a human perception. A measurement between one event and another. The "phisics" of time is bunk.

[@routex1]

Sean Carrol is so articulate and masterful at summarizing big concepts to the laymen. His Mindscape podcast is a true gem.

[@bobbeckstead8340]

Articulateness and masterful summarization are not discovery. They are the tokens of entertainers and con men.

[@Sean420-f6l]

Hmmm maybe because Oxygen gives both birth and rebirth but also is a very volatile carbon element…meaning energy is not created nor destroyed. And we all know the term “oxidation.” What is that? Hmmmm oxygen, oxidation… hmmmm. So oxygen both provides life and at the same time kill’s biological material. we know when everything is crumbling around us. And you’re an idiot because there’s more than 3 dimensions and that’s the simple conclusion of moving a spacecraft from the ground to past the atmosphere. You don’t need to be a biologist or scientist at all when it comes to energy. We cannot create nor destroy it. Simple as that. Let’s not forget Trump saying “clean coal”😂😂😂haha I love it. What a fucking idiot. Let’s not forget there’s an entire county burning because of coal and it’s still on fire 30 years after. Sounds familiar right? “Anti-oxidation or anti-oxidants” hmmm interesting. 😂and what has the drug and food administration done ? Nothing to fix the problem we have. And when was that? Oh during the four year trump one time president 😂

[@Sean420-f6l]

“Thermal equilibrium is found in a test tube” doesn’t have anything to do with real solar rays. It’s a fake truck republicans use because when solar panels are finally set up they do actually work. But so many of these asshole republicans have money invested in coal and oil (thank you bush 😂 you didn’t do anything)

[@bobbeckstead8340]

@@Sean420-f6l You're blathering.

[@bobbeckstead8340]

@@Sean420-f6l You gibber.

[@ruellerz]

Sean Carroll's mind takes flight, Unraveling time's mysteries, day and night. Physics' dance, a mesmerizing show, With each tick and tock, new insights we'll know.

[@jmac6248]

I heard a really good time travel joke tomorrow.

[@lunam7249]

i know, i laughed about it yesterday.....

[@kevinbeazy]

Haha love it

[@anuraagdhanik5110]

Finally I found you.. aren't you telling about the joke I told you 2 years ago?

[@adamdel4]

I’m not going to get it.

[@shanu7uday]

Please check your facts! I’m yet to tell that joke to you yesterday.

[@linfan6596]

"The answer to the question of what time actually is, is still not apparent here. Time is defined as the sequence or collection of events, but what exactly is an 'event'? If everything is made of matter and by that made of energy, and there is a fundamental relation between time and energy. Then this same relation holds universally as long time and energy are related. What I propose, in this comment section, is that time and energy are not two separate physical quantities but are in fact interdependent. Time is the change of Energy. A change in the energy of a system, Entropy, is what registers as an event and that event registers as time." - Keyboard Physicist

[@thegeorgehull]

I understood entropy so easy when he talks...if I had a teacher like him in school...I would loved to learn more.

[@sinaolfati6612]

Because he is explaining only the interesting parts of a boring sea... But in academic ways you have to learn/teach every drop of a boring pond.

[@hamtoriz1084]

i could listen to him talk forever. it's so fascinating and intellectually stimulating, yet easy to understand.

[@michael-4k4000]

I like Neil or Brian Coxs voice better

[@dentistrider3874]

I had a question very related to this a few weeks ago: "How could life have come about if the entropy of a system has to increase?" The answer I found is that the entropy of a *part* of a system can decrease or stay the same if the entropy of a whole system continues to increase. And life, really, as he said, is a system that feeds off of entropy, we are fine tuned by the edge of evolution to adapt to change and to overcome it, in a reasonably stable solar system with a constant source of energy and somewhat constant conditions.

[@davidreidenberg9941]

Exactly. Entropy is always increasing ON THE COSMIC SCALE. That doesn’t mean that occasionally local areas can experience a decrease in entropy. Living systems maintain a low entropy state only because they interact with their environment. The real mystery is what caused the low entropy state to begin with.

[@Trimmxthy]

@@davidreidenberg9941 Imagine the cosmic scale is just a local part of an even bigger scale 😅

[@batouttahell454]

Is there a God in this?

[@dentistrider3874]

@@batouttahell454 In any serious discussion of cosmology or physics there never is.

[@perrygreen8582]

​@@batouttahell454Of course there is, logically speaking.

[@danielshults5243]

Sean Carroll is definitely one of the best science communicators around.

[@alexgoslar4057]

I love your explanation, Sean Carroll. It is a keeper. Personally, I am making difference between time and timing. While time is immeasurable, timing is within a measurable scope.

[@PixelZoft]

The big mystery is that the arrow of time is the same everywhere and that it never ever changes. So time definitely has a direction. If you look at a pool table break on a video you can (with almost 100% perfect certainty) know the direction of time of the recording. No one needs to tell you. Ever. That you cannot tell from a small simple quantum physics event does not mean that it is not there. As soon as chance comes into play it can only go one way. So why is that? Because that is just how the universe works, in every single cubic cm of space we have ever looked at. I find that fascinating.

[@Sky-B14916]

When people say they don't have time ,they are always true ....they don't actually have time 😂

[@willdesouza3968]

time has them

[@EefLeaf01]

@@willdesouza3968 right where it wants them >:)

[@Sky-B14916]

@@wailinburnin time goes far beyond expectations 👀

[@dennisgalvin2521]

@@wailinburnin Where does the time go go? "It's around in a circle shouldn't we know, the clock and the calendar tell us of it's way's 24 hours 365 days. So as for this mystery that's dumbfounded generations, it's just an illusion from the harnessing of Earth's rotations". Bruce Dillon.

[@71borto]

I have no time to listen to your nonsense on time. 😁

[@enchanted_swiftie]

A man with this much interesting information can pass his all day talking with himself without a need of anyone.

[@Leo.Wirabuana]

Best Teacher Sean Carroll.

[@supernatural_forces]

Have you heard of Brian Greene ? See, 'What was God doing before Creation?' from the channel Rational Believer. Probably you would get something more enlightening. Though there's a flaw in this question, its just for conceptualization.

[@nathanwainwright0]

The issue I have with a lot of these explanations is that the argument we have for existence is that we were very “low entropy” (order) when matter was spread across the cosmos, but then things became more complex when “high entropy” (chaos) and the evenness became unevenness in planets and creatures. That chaos made things that were, by their very nature, more complex, but that level of complexity requires vast amounts of energy to maintain in a stable order (low entropy). Since things move from order to disorder (second law of thermodynamics), you have to have some unique situation where disorder becomes order, you need some force pushing back high entropy to create a low entropy environment. We know the 2nd law is still in effect as if we leave a complex being or machine to sit, it becomes less complex, eventually non-functional, and then eventually breaks down into its simplest molecules. So what introduced the low entropy system, what maintains it, and how long does it continue unless something invests in it?

[@Arete37]

Yes. And if there was a big bang, why? What initiated it? Something never comes from nothing. Before the big bang, what? Gases swirling around? WHERE DID THEY COME FROM? It's maddening, not to know.

[@jesusmoreno4501]

Wow! Very piercing question and well put reasoning

[@lilori28]

Very interesting I would like to know the answer now too

[@RogerMillerInVA]

You make such lucid, clean, and clear videos. Your pacing, content, and imagery are pitch-perfect. Thank you.

[@fatsdom]

You are very welcome. Please keep watching for more videos.

[@ahedkhattar667]

Big think professional editing+sean carroll brilliant presentation= an absolute masterpiece

[@HIIIBEAR]

These videos are so well made.

[@1776adb]

Our use of time is all that is important.

[@tayzonday]

Time is different than causality, but we use them interchangeably.

[@fullyawakened]

No

[@Mustachioed_Mollusk]

@@fullyawakened possibly

[@daz97]

The general population does that with everything, and as a result we live in a world of people who think they know everything about everything, because they spent a day learning about it on some random videos lol But because they simplified it so much it completely misses the point... If your foundations of study aren't done correctly then your end result will be wrong. Time, for me... Is just the measurement of motion But I'm not an expert in this area, and I never pretend that I am... Shame no one else these days can say that about any subject at all, everyone thinks they know everything because they read about it in Wikipedia lol Or because a Liberal college told them it so don't question it just obey lol

[@ddv2nine722]

If you think on flat spacetime then they are not So different; for two events on the universe to be causal with each other, there Must be a difference on time, but you must also specify how far they are separated. So causality is a property shared by events with specific time And space separations. If light can connect those events, then they are causal.

[@EonsEternity]

@Daz this is basically what i find it to be as and when you really think about it the way we measure times with clocks the units of measurement are the tools themselves, the clock hands, and we based that off the sun, our rotations and revolutions around it and narrowed it down more but really we're just measuring change, we just measure the change of everything by using our constants for change, translating it like we translate imperial to metric, etc. How something so simple can also be so complex and amazing is just... amazing. I can't think of another word right now, but I just love the thought.

[@FISHUNTREECOUNTRY]

Physics can't actually explain entropy, because the exponential expansion and diversity of the universe is not only from the big bang, but also from the unseeable mesh interweaving the universe in complexity, that steers the direction of things not entirely based on physics or math. There is more that we don't know than we know, and physics is a limited study with alot of great answers, and alot of gaps without answers. There is a bigger encompassing undiscovered formula, that includes both quantum physics and gerneral relativity. .... but we don't know what it is yet.

[@tayzonday]

Also - with the expansion of spacetime - is the entropy of the universe REALLY increasing? Is the expansion itself a byproduct of increasing entropy? Perhaps space, as a medium, can only accommodate so much entropy per unit of “density” and expands elastically when more entropy is dumped into it?

[@tylercriss6435]

Entropy isn't really a physical thing, like you can't hold a unit of entropy. It's just a way we describe arrangements of things that do exist, like atoms and the changes between their relative states of energy. In this case, maybe it would be less the entropy doing the expansion, but more likely the atoms or the energy. Maybe!

[@ddv2nine722]

You could imagine the box at 3:38 to be expanding, meaning that the distance between balls is increasing but the relative distances staying constant. Since entropy really measure your failure to predict the state of the total system knowing a tiny part of it, then by this picture it should be constant (maybe), we should keep investigating.

[@kaibuchan]

I FEEL LIKE TAY ZONDAY, I FEEL LIKE TAY ZONDAY, I FEEL LIKE TAY ZONDAY, I FEEL LIKE TAY ZONDAY.

[@MrSatnavatron]

what about 'Stop engines' -- instead of speeding up - why not slow an object relative to the space time curve ? - multiplying the various speeds of galactic forces ( solar , galaxy , local group speed) we could travel much further than lightspeed if all those variables in "motion" are taken into account... cheers thanks -- send the Nobel prize to po box ....

[@ivy_savage69]

Wrong idea

[@Hybrid869]

He brings up a lotta good points around Time but it makes me feel like there's enough open questions to keep "What is Time?" on the table.

[@okgroomer1966]

It never left the table. We discuss theories on such topics, not facts.

[@philjamieson5572]

He seems, to me, to make sense of things that have really puzzled me all my (very long) life. I am sincerely grateful that he's spent so much of his time and effort to do so.

[@JonnyUnderrated]

well im not sure he did it specifically for you Phil. But yeah it was cool.

[@philjamieson5572]

@@JonnyUnderrated Yes. It was, as you stated in your well expressed, casual and throwaway style, 'cool'. I'm assuming that your comment was meant solely for me. I may be wrong with that assumption.

[@JonnyUnderrated]

@@philjamieson5572 Your casual utilization of commas has thrown me for a proverbial "loop" , Phil. I was trying to ingest your verbage and je ne sais quois but they took me off guard and now I'm all messed up. But yes, I was trying to communicate with you Phil.

[@suhail_69]

@@JonnyUnderrated what are you both doing here 😃

[@JonnyUnderrated]

@@suhail_69 im trying to chill., our dear friend PHIL here is on some kind of diatribe again

[@bunklypeppz]

I'm not convinced of his point in opposition to the notion that 'life' inherently fights against the increase of entropy. He makes a good point with regard to how the process of increasing entropy is not necessarily the enemy of living systems in every regard, but speaking specific to the processes within living biological systems, they almost exclusively strive to reduce entropy within themselves. If this were not the case, injuries, infections and even aging would not be detrimental, because there would be no reason to expect that their results would have a negative impact rather than a positive one. For example, head injuries would be as likely to make you smarter as they are to cause cognitive problems.

[@TheSLK66]

“I know what it is, but when you ask me I don't.” Saint Augustine.

[@dennisgalvin2521]

"I know what it is and when you ask me I still know" Bruce Dillon

[@helifynoe9930]

It is better to explain "Motion", since Time is merely one of the four dimensions of the 4D Space-Time environment. As I have shown, by looking at motion in the 4D sense, it makes Special Relativity(SR) so easy to understand, or even discover it on your own, and allows you to derive the SR mathematical equations in mere minutes, despite knowing nothing at all about physics.

[@10sqrftthisthat]

Unfortunately, the question of why we age has nothing to do with time but instead it’s a design issue.

[@dennisgalvin2521]

Yeah, time is just a system that measures the process that makes us age.

[@sixman9]

This is correct. Time is emergent and the measurement of the comparison of rates of change. Time is not an energy or force that asserts itself on objects. Milk does not got bad because 2 days have past, it is because of bacteria and heat energy, we are just able to expect a similar result, having previously seen a certain amount of days or hours pass under similar circumstances.

[@bobbeckstead8340]

Thank you.

[@bobbeckstead8340]

@@dennisgalvin2521 It measures the rate, NOT the process of aging.

[@dennisgalvin2521]

@@bobbeckstead8340 To be specific, it measures he rate of the process.

[@Signaman-z9d]

I know nothing about what he's talking about, academically0 but I'm fascinated by all he's talking about. Understanding Space including earth is mind blowing. All Scientists have my admiration for what they have achieved in their respected fields in such a short time. On the shoulders of past giants 👽🖖

[@brendangoosen]

Time is our abstract explanation of change. It is our illusion.

[@bobbeckstead8340]

More precisely, of motion - change is derivative of motion.

[@Sam-we7zj]

@@bobbeckstead8340 no idea what motion without time means

[@cosmobiologist]

Just met Sean at a meeting in Abu Dhabi. Loved his talk and chatting with him!

[@johnpetkos5686]

Sean Carroll is international treasure.

[@57w7w]

By slowly pressing a box internal pressure would rise and the walls of box would heat up. Box would remain pressed in position that force heat of walls and heat of walls would be collected for electric energy production or for heating , keeping the box in pressed position would be done whit some closed brackets so no input of energy for keeping the box pressed so all its heat would be used to produce output of energy

[@michaelccopelandsr7120]

Time is fascinating. I worked the subway stations for nearly 10 years. From one end of the city to the other. Every so often I would notice the city would be saying that, "Today just flew by" or "The day was just dragging along." How can an entire city complain about the same time paradox unless it was effected by it. Maybe a time distorted bubble the earth passes through in its revolution around the sun. Maybe random waves of time distortion hitting the earth? Maybe they're randomly given off by the sun. Maybe they're from outside our Terran system and reach us in intervals. ???? Ti-i-i-ime, is on my side. Yes, it is!

[@yan-amar]

I would rather suspect a bias of confirmation on your part, I'm sorry. For one if time stretches, then our perception of time should stretch with it, shouldn't it ? Well, maybe not. But there are other factors to take into account. The whole city is subject to the same weather, it's the same day of the week for everybody (monday VS saturday, the mood differs). Plus city-wide, nation-wide events affecting the mood. All the people taking the subway at the same time, probably have a common lifestyle (working day jobs), they are linked socially. Etc.

[@michaelccopelandsr7120]

@@yan-amar that's fine. You don't have to believe me. Great part of this is, this "phenomenon" is reoccurring. Just spend a year or two in the subway. Rush hours are best. Stopping at every station on the line. From students to working class to business class. You get to hear how an entire city's day went. After a year or two, you'll see it, too. The pattern in the chaos. ;-P

[@simesaid]

@@yan-amar while everything you say about social uniformity and cultural synchronicity is true, time _does_ stretch. Or to be precise, matter travelling through spacetime _shrinks._ But time itself does have elastic properties, beyond merely those of relative perception. As Einstein showed in special relativity, and as has been proven in every experiment ever conducted since the theory was published in 1905, how you move through space affects the way that time passes. Specifically, the faster one moves through space, the slower one moves through time. There is a very precise trade-off that occurs in order for the universe to maintain an upper-limit on the speed that matter can move through it - namely, 291,000,000 metres per second - the speed of light. Travelling at the speeds we do here on Earth the effect is almost unnoticeable, though for a few thousand dollars you can buy clocks accurate enough to see for yourself. At the speed that satellites orbit the Earth, around 27,000 Kph, the effect is strong enough that Google maps would be a useless app if the effects weren’t adjusted for. And should you travel out to Alpha Centauri at about half the speed of light before returning home to Earth again, you’d find that everyone back home had aged by about 40 years, while you had only aged 5. Einstein showed that time is personal, that there is no such thing as a universal time (as Newton had believed), and that it doesn’t even make sense to say that there is a “same” moment of time for any two objects in the universe. There’s a 5pm in NYC for you, but only you. Time is personal - the faster you move through space, the slower you move through time. Trippy, but absolutely true. Cheers!

[@simesaid]

@@yan-amar I should have added that the shrinking and expanding component is called ‘length contraction’, when travelling at relativistic speeds matter experiences time dilation (the slowing of time), and length contraction (where matter is ‘squashed’ in the direction of momentum. Again, here on Earth, and travelling at our speeds, the effect is completely imperceptible. Driving a car on the HWY for example, will reduce its total length by about the width of a proton… Yeah, I wouldn’t worry about that one too much either :/

[@Whoisreading]

I believe you. I'm far from your location, but I noticed the same thing, not in a subway but in live as a whole. I even got to name it, I call it "wave" or maybe a " low or high center of pressure" of some sort as in the atmosphere but of course not related to weather. I even avoided some corners or gas station because I "felt" as if a particular location "brings" a certain mood or even to happens. I though sometimes myself a bit superstitious for this but here you are talking about the same thing.

[@ryanmccutcheon4198]

The entropy explanation makes sense until you think about the fact that we decrease entropy all the time in our daily lives and it has no effect on time, and certainly doesn’t reverse time. I like Richard Mueller’s theory from the book “Now: The Physics of Time.” Basically, his theory is that since spacetime is expanding, there is more time being created and we are always right on the edge between past and future and experiencing the new time every second that passes by.

[@wtfserpico]

That is far more satisfying. I feel like he kind of lost the plot so to speak in his explanation here, and I kept waiting for him to bring it back around and then the video was over.

[@deadlinetrader]

I just finished watching "The mind-bending physics of time" by Sean Carroll and I have to say, I really enjoyed his unique perspective on the subject. I found it fascinating how he was able to explain such a complex topic in a way that was easy to understand. I particularly liked how he delved into the concept of time being a "block" and how this theory can help to reconcile some of the discrepancies in our current understanding of physics. Overall, I thought it was a thought-provoking and enlightening video and I highly recommend it to anyone interested in the nature of time.

[@Cosmo_P0litan]

Someone had a school assignment... lol.

[@MrFlameRad]

100% a chatGPT comment lol

[@bobbeckstead8340]

He "reconciled" nothing - you've been taken in by pseudoscience.

[@Cosmo_P0litan]

@@bobbeckstead8340 Prove your statement.

[@bobbeckstead8340]

@@Cosmo_P0litan What an inane challenge.

[@JasonFolkerts]

It's amazing to me that many physicists refuse to acknowledge there could be a designer outside of the bounds of the universe who is conducting all things. Call that force god or whatever identifier you like. However, there seems to be evidence everywhere given the characteristics of the universe mysteriously finely-tuned to enable human life.

[@Arete37]

Hang on. What do you mean, "outside the bounds of the universe"? Where would that force or god be? How can there be an outside of the universe, that would be universe, too. What's just beyond that? More.

[@zuhaibkhan3694]

The intricacy of entropy renders the Newtonian world in abstraction. It’s a labyrinth. ❤

[@JasonWalsh-b4n]

YOU ARE CORRECT ABOUT SPACE-TIME, PROFFESSOR SEAN CAROL. I, TOO, DON'T HAVE THE TIME TO WATCH THIS, OR DO ANYONE WHO MATTERS OR DO ANYTHING! PERIOD❤

[@It__From__Bit]

Sean says the universe began at it's lowest state of entropy and has been getting higher and higher ever since. Entropy is defined as "a lack of order or predictability; gradual decline into disorder." But when the universe began forming galaxies, solar systems, suns, and planets, it actually became far more ordered than how it began. It just stared out as a mass of unorganized matter and energy, then organized itself into the structures we see today. This seems to contradict what Sean is saying.

[@mccorkleee3375]

You’re misunderstanding entropy. Don’t look at individual galaxies and solar systems, you may look at the entire universe as a whole. You’re right, it initially started out as one glob (low entropy) and is spreading out and developing new celestial bodies over time (high entropy.) The matter on earth and in our solar system/galaxy has come from many, many dead stars and galaxies before us.

[@6piyushc]

No... universe as a system is moving towards high entropy. There are local systems like stars, galaxies, crystals, organisms, etc. that are low entropy but the overall entropy of the universe system is always increasing.

[@It__From__Bit]

@@6piyushc So the prediction is that all galaxies will eventually lose the ability to create new stars/solar systems? Have the Hubble or Webb telescopes been able detect galaxies that are in decline? If so, how do they determine that they're in decline?

[@rolandlastname5532]

When after the big bang a hot cloud of gas is expanding, it is also cooling down, so the entropy increases but nor that much. Then, when parts of the gas cloud is condensing to form stars, the temperature goes up. Here, condensing means entropy decreases and getting hot means entropy increases, and the net effect may be entropy increases but not that much. So far no obvious contradiction

[@blanchsdp]

The steady increase in entropy, in addition to being beneficial as you point out, helps us keep track of cosmological time and explains a lot of the local features of time (aging, ice melting, etc.) That increase is something that takes place in time; not something that explains time. Suppose someone pokes a hole into a whole nuther Kosmos and the total entropy of this K begins to decrease as a result. We can speak of the time before and after this happened. Time's arrow survives.

[@DutchBoulders]

Wow the clarity of his explanation makes every concept crystal clear! Thanks Sean

[@JonnyUnderrated]

so will you invest in shiney DIAMONDS or shiney GOLD Sir ?!??

[@AYVYN]

That perfume example was genius. Like many, I equated entropy with disorder, but now I realize that it's possibilities.

[@bokchoiman]

I think time seems to slow down when you're engaged in transformative activities. The constant changes in your environment fill your time with memorable moments, making you feel like you've actually made good use of your time. When nothing changes in your life, the relative change between one moment to another is small, and so your time speeds up. You've few moments to look back on and it feels like you've wasted your time.

[@twotubefamily9323]

That's how individuals experience time - no relationship with space/ time whatsoever

[@bokchoiman]

@@twotubefamily9323 Notice i wrote "seems"

[@jimbonacum8917]

I can't recall who said it but the reason we have time is because without it everything would happen all at once.

[@willbrink]

I'm especially fascinated by the idea time itself does not exist but is an emerging property of entropy, which also only goes in one direction. For some reason, that one feels right to me. Why, can't say.

[@blijebij]

If that would be true, at a blue shift (not a red shift) time would go backwards as entropy gets lower. but It does not. Entropy is an emergent phenomena from complex systems. It shares a lot with time but is not time it self nor does time emerges from it.

[@willbrink]

@@blijebij Entropy and time only go in one direction so there's no going backwards and it's an idea many physicists suspect is correct. The universe started at a very low entropy state and only increases, which this vid discusses.

[@blijebij]

@@willbrink If entropy makes time goes forwards then when entropy goes lower, blue shift time should go backwards. It does not. What I find more logic that entropy is a big part of change, you could even say is linked to most changes in the universe. Time is linked to all changes in the universe. So they seem to fall almost always in one line. So its easy to think entropy is time. But quantum fields occilate, thats why particle pairs pop out of the vacuum of space. Quantum fields will always occilate but that doesnt mean automatically entropy rises for a quantum system. So not all process work by entropy. One thing I realize though from our talk (pondering over it) that you are correct when you link this to spacetime. Then indeed entropy and time always fall in to one line up. But for quantum fields this does not have to be so. So within spacetime if u take just that compartment, you are right.

[@willbrink]

@@blijebij Bottom line is we don't know, which is amazing considering like gravity (something else we know amazingly little about...) it's what we experience every day of our lives. There's also theory time is an emergent property of quantum fields, and others. Time and gravity are interrelated also, exactly how, also unclear. If they could just find that graviton... :)

[@blijebij]

@@willbrink yes hehe its an exciting field of interest :) universe&reality are fascinating.

[@RobRoss]

I think Time is the same kind of philosophical issue as Free Will. In the case of Free Will, most philosophers tell us it doesn’t work the way we think it works. But Time and Free Will are both human experiences, regardless of the underlying mechanism. When people say “there is no Free Will,” what they really mean is that your idea of what Free Will is isn’t actually how it works in the Universe (see Compatibleism for an idea of how it might actually work.) Similarly, even if Time is emergent and not fundamental, we still have this experience we call Time. If you are Julian Barbour and believe that “time doesn’t exist,” well the fact that “things change” is how we subjectively experience “Time,” whether or not the underlying physics is different from our intuition.

[@batouttahell454]

I wish you spoke more about free will!

[@Arete37]

Yes, if nothing changed at all, ever, would there still be time? Time just seems like a measurement of change.

[@StanCarles]

Sean Carroll is a great teacher!

[@JonnyUnderrated]

Youre a good student Stan.

[@DoubleplusUngoodthinkful]

I see time as having 3 dimensions like space does. In fact, I believe it's really just another 3 dimensions of space. People think that you go forward and theoretically backward in time. I believe that moving through space makes you move through time. The changes we make in space change our direction in time. You're not going linearly forward through time as much as steering through it, like driving a car. When you turn your steering wheel in a car, you turn left or right in space, but you do the same in time. If you went "back in time" and turned left, you would see events that, to your perception, never happened, just as if you turned your car around and went back the way you came, but then turned onto a side street you did not traverse before, you would see things there that you didn't see before. If you stop completely in space, you might very well stop completely in time. We don't know how to stop in space, however, as we can only use bodies in space for reference, all of which are moving in an unknown absolute direction. We know what speed we are moving relative to the object on this planet around us. We know how fast our planet is moving relative to the sun and other planets. We know how fast our sun is moving relative to our galaxy. And we know how fast our galaxy is moving relative to other galaxies. But we don't know in what direction this whole swirl of activity of all of the galaxies collectively is ACTUALLY moving, or how fast. So while time might seem to be on autopilot, it is only as much as objects moving through space.

[@Aryan37419]

This video is a fascinating exploration of the interconnectedness of time and entropy. Sean Carroll does an excellent job of breaking down complex concepts and presenting them in a way that's accessible and thought-provoking. The idea that time is merely a label we use to distinguish events is mind-boggling, and the discussion on the arrow of time and its connection to the Big Bang is truly intriguing. I appreciate Carroll's challenge to the notion that life is a fight against increasing entropy, emphasizing that life actually owes its existence to the increase in entropy. It's a fresh perspective that opens up new possibilities for understanding the emergence of complexity in the universe. Overall, this video has sparked my curiosity and left me with a lot to ponder.

[@donniedavis6163]

Time is just something that allows things to happen. Simply put...if time didn't happen, nothing could happen at all

[@adrielamadi952]

To be honest, this guy really didn't explain time

[@erikkuykendall6826]

He is explaining the physics behind time not necessarily time itself.

[@ligitmuffin]

Or maybe his understanding is much higher then ours so it seems like he didnt when he actually did.

[@watcherofthewest8597]

time exists because time is needed for matter to evolve.

[@rohanjagdale97]

Time exists in our brain

[@kurtsydavis7517]

Where our brain exist?

[@bobbeckstead8340]

Bingo! All of our daily experience exists in our minds. Only rigorous science can show us some of the approximations of reality that is independent of our minds

[@lowtuned]

imagine a different universe with decreasing entropy. where you have memory of the future and you know what's gonna happen, but nobody knows what happened in the past. how cool is that?! and you'd have smart people there thinking "imagine we had increasing entropy. like you only have memory of the past, everything already happened and you wouldn't know what lies in front of you, so boring!"

[@JohnHirsch88]

Y'all need to chill with the background music

[@monsoonkairos234]

Wow what a great explanation sir!!❤✨

[@Exen88]

Sean’s got a great style of communication. I very much enjoy all of his talks. Every time.

[@FISHUNTREECOUNTRY]

Time is entangled with perspective for living beings.

[@Polymathically]

I know that time isn't linear. We just think it is due to the limitations of human perception. I occasionally have dreams that come true. I'm not talking metaphorically, or about deja vu. I mean dreams that are very brief, but clear visions of random future moments. Just long enough to get the layout of a place or part of a sentence. It's never anything useful, like saving lives or winning lotto numbers. And I never know the context or how long it'll be before it happens. Sometimes it takes weeks, months, even years. I also have memories of moments that apparently never occurred (just like the Mandela Effect, but in my personal life), and objects have either moved or vanished entirely. As someone who studies science, the fact that I can't prove or replicate any of this is incredibly annoying. It sounds like symptoms of schizophrenia, but all the therapists I've had over the years have said no. My current therapist has even suggested I've attained some kind of spiritual awareness, but I don't what to think about that. My theories are that 1) all events are either happening simultaneously, and we can only understand them in a certain sequence. Or 2) multiple timelines exist simultaneously and sometimes interconnect, but the mind is supposed to remember only one at a time. I just wish there was a way to test them.

[@mkaufmandev]

The dropped coffee cup is something Stephen Hawking talks about in 'A Brief History of Time'. He says time travel to the past is not possible precisely because when we drop a cup it shatters into many pieces. We NEVER see it go back together in reverse. This was Hawking's analogy.

[@RTL2L]

Great video, thank you! Love it, when BT is about science, not agendas.

[@rexxx4fun]

Daniel Schmachtenberger's talk on Emergence takes a crack at some of these questions.

[@apolloniustyana7372]

I wish I actually knew if reaching a state of maximum entropy would mean that there is no longer Mass and therefore no longer time but I am extremely impressed with Roger penrose's conformal cyclic cosmology theory it's very impressive the way he was able to think out of the box on this one I really like the conformal geometry part also I wish I was better qualified to like it even better or just say no this is wrong

[@phm19880]

I hear you. I have been impressed of sir Penroses ccc theory. It just is impressive, and like u said out of the box thinking, challenging other scientists in a good way. Overall I have been fan of his thinking and I have watched some of his lectures from yt. You have a great taste 👍🏻😅

[@1viewer1]

Absolutely beautiful explanation. So when an object is able to escape the gravity of our giant vicinity toward another celestial sector with weak gravity (to do more,get old faster) or stronger gravity (to do less,stay as same age longer), that’s how time travel work, ie. Being away to deep space and missing out, either for long or short duration) of the time of those left behind in earth.

[@Bobalicious]

“Time is an illusion. Lunchtime doubly so.” ― Douglas Adams

[@thebeezknees]

Hammer time is real damn it.

[@bosun99uk]

Thank you for your Time 😊

[@Salted_Potato]

Probably the best explanation of time i have seen in a video, amazing explanation from Sean and thank you Big Think for the illustration and platform

[@ochjim]

Except that he didn't actually explain what time is . . .

[@Dyslexic-Artist-Theory-on-Time]

Time can be explained as a process of energy exchange formed by photon electron interactions. We have photon ∆E=hf electron interaction continuously transforming potential energy into the kinetic Eₖ=½mv² energy of matter, in the form of electrons as an uncertainty ∆×∆pᵪ≥h/4π probabilistic future comes into existence. All it takes for this to be logical is for the spontaneous absorption and emission of light waves to precedes absolutely everything that happens in our three-dimensional world.

[@deepaktripathi4417]

Thanks a lot for bringing such wonderful videos!

[@DamnBoiya]

Entropy is my favourite concept in the course work I have completed, order to disorder. Always stuck with me too. Great video so far

[@jayshomer4191]

Time is simply man made, as a unit of measurement. The eternal moment that has always existed and always will, is the brain twister !

[@rasulsamad5860]

Well said my pops always told me that

[@PaulJohn283]

It’s all been explained in the Bible you big dummy.

[@ochjim]

Yep. It doesn't exist, except as a manmade construct - a way of imposing order on events/action in order that we can make sense of it all and plan our lives . . But it is based on physical constants of atoms in order to be accurate, and therein lies the problem when we move too fast - near the speed of light, when the properties of atoms are so affected that the constants no longer apply/are changed.

[@BenJehovah6969]

​@Jim Hogg Not entirely true. It was conceived as a tool, but like any tool it could be used to build good and bad things.

[@BenJehovah6969]

​@Jim Hogg Not entirely true. It was conceived as a tool, but like any tool it could be used to build good and bad things.

[@Williamb612]

Time is a mental construct which we create to separate events sequentially, so that we can exist and maneuver and navigate them. Truth is everything is all at once

[@kj475]

We do have the ability to affect our past. The decisions we make today and in the future will have an effect on our future past. 2 years ago I had the ability to impact the events that occured 1 year ago.

[@kevinjenkins6986]

I love listening to brilliant physicists dumb stuff down for us, that in and of itself is an amazing feat 👍

[@philjamieson5572]

Kevin Jenkins: Excellent comment. Well said.

[@Diponty]

I love bots.

[@sumit06pattnaik]

Beautifully explained. Loved it

I saved my self a lot of TIME by remembering that no one knows what it is. Therefore there is no point in watching this.

[@jeffrowlette]

Our shift in entropy is proof of "God". Life decreased in entropy. That required an outside intelligent force.

[@TheHonestPeanut]

I love when people sidestep questions by saying the question isn't the question lol

[@marvcapitola4262]

Only trouble I’m having with the pictures or videos of the Big Bang is, it always demonstrated as moving in one direction. Would it have not expanded as a sphere?

[@coolaa7]

Is this video mislabeled or am I just that much of an idiot?:) I definitely missed the part about "The mind-bending physics of time."

[@peterdamen2161]

Exactly what I thought, and commented about. Carroll says around 1:21 min that what time is, is not a question. But he doesn't explain what time is. So I can only deduce that he dosn't know what time is.....

[@rum-ham]

This video explained almost nothing. He simply restates simple concepts in a way that makes it sounds insightful. Reminds me of The Onions "Onion Talks" videos.

[@aeendale100]

Time to get off youtube and go to sleep.

[@Historylearn879]

😂

[@nrouzbeh]

Time is not like gravity, it purely exist because WE experience IT. I don't know how to expand on that, I'm not a physicist or .... But this is what i understand, we have to conceive things as our minds can, so we believe that something has to have an beginning and an ending, our minds can not understand infinity, we have a memory and we have self awareness thus we know we are going forward in SOMETHING so we gave it a name. Maybe i sound stupid or unclear cause english is not my native language 😅 sorry about that

[@bobbeckstead8340]

Exactly. Time is not a physical phenomenon - it's a psychological one. When physicists start telling you what color or time or life is, run away.

[@freebk161]

Perfume in a bottle 👍👍👍. The complex concept described in one line. Thank you Sean 😊

[@shashidharshettar3846]

Live Long Sean to keep on educating us the Non-Physicsts

[@moicao4568]

Truly mind-bending ! After watching this, I'm a little more confused than I already am. Sticking with Earth Time , I guess...

[@idahospud6979]

WOW! I actually understood what he was trying to explain!

[@darrinwebber4077]

I believe "time" is just our perception of the expansion of space. Always forward

[@grapes9h5]

Love this. Reminds me of why I enjoyed the movie Tenet so much.

[@davidreidenberg9941]

When someone says “ meet me a 42ed. and 7th., at such and such a date at 7:30 PM, what do they really mean? They mean when both of our watches (a mechanical device which are presumably synchronized) reach what what we have previously agreed is 7:30 on a specific date again previously agreed upon, we will show up at an agreed place on the map in NYC. It’s purely a convention designed to organize human activity. Nothing more.

[@dennisnew335]

we live in a universe in paradox everything inside the universe is moving forward through time, the universe itself is moving backwards through time, this is why it's so much larger in the past, instead of appearing condensed like it's supposed to look. we are either looking back in time or were not, you can't have it both ways, if we are looking back we should not be able see the result of accelerated expansion so far back we should not be able to see as it is now.

[@safebox36]

I'd have said there _is_ a special direction of space, it's just more scalar than vector. There is a limit to how small something can get before it effectively can't "be". Quantum mechanics operates on all scales, it's just that the more of something there is the more variables come into play. But as you measure smaller and smaller, eventually you hit a limit where no quantum wave can possibly exit without be needing to be divided; which by definition of "quantum" cannot be done.

[@platinumpineapple9943]

Our brains can actually speed up time and slow down time depending on whether we are bored or sick or in harm. vs when we are occupied, having fun, relaxing, etc.

[@StuartHallPlectic]

Enjoyed listening to this explanation of time and entropy that both started with the big bang. To state the obvious, both are also forms of organisation. 😊

[@jimmykaushal9982]

He mentioned he talks about time all the time now he can say he talked about entropy all the time. All i heard is entropy but how time in 4D looks is what I wanted a lil bit explaination but dont take me wrong this video was still very informational

[@piyushjoshii]

Learnt a new word today : Entropy! Thanks. I’ll try and use it now.

[@youdonthavetoreadthispost.5850]

To continue my thought ; A ; "Change of State" ; has occurred at vaporization - entropy accelerates into dispersal - acceleration slows without confinement over distance - state of entropy relates to distance over rate of travel - as rate of travel slows down ? then so does time ? somewhere out there is something that we could catch up to ? and time is not linear - but circular. 🤔 I have no idea if I'm right but this bent my thinking around a familiarity i.e. atomization. Just a curious old man nothing more than that. 😎

[@mariannefischer3613]

It helps to remember that time and causality are not the same thing.

[@johnsongibbs6567]

This is an equivocation suited to entropy. Time describes universal motion and is calibrated by clocks.