The fluency and clearness in they way he talks is perfect.It makes those who don't have a physics background help get a grasps on these fundamental ideas. As can be said about all the other talkers on sixtysymbols, and Brady's other channels. Bravo.
Brady, I love what you have done for us here with all these channels. I don't think I've ever learned as much as when you interview these brilliant people. And your way of asking questions just shows what a great view of life you have and how you really burn for these types of questions. These channels are my go-to place whenever I need a thoughtnugget, thank you so much for doing this for us!
Please tell Sean that he needs to narrate a documentary at some point in his life. He is so good at explaining things and I could easily listen to his voice all day!
I love the explanation. Also I love the equations on the board in the background. Details like that can make one feel a lot better, and contribute to a video's quality.
I could listen to Mr. Carroll talk for hours. His mannerisms, speech patterns and inflections make him very interesting to listen to, while his explanations are well articulated for folks who haven't a clue what he's on about going in. He makes complex subjects easy to listen too, and hopefully learn a little from.
What makes these videos damn awesome is the fact that Brady always asks the questions the rest of us are thinking about. That's why I love these videos and think that these are more educational than many straight up explanation or teaching videos of the same topics.
I left a glass of water on my bedside table last night and when i woke up there was ice cubes in it. Forgot to say I went to sleep outside at the south pole...
I gotta look that up in that case! In the few videos he has been in on sixty symbols he's starting to become one of my favorite "stars". The way he explains things is extremely clear and always spot on. Enough detail to keep it relevant and correct, but simplified enough so us normal people can understand it in one go. Quite honestly I'm baffled after every video with him in it. Such a smart and inspiring man to listen to.
what an incredibly enriching chat! this channel is a goldmine for the mind, this should also find itself featured on the front page of youtube alongside of all the banal content.
By the way, thanks for being probably the most insightful and broad-ranging youtuber there is :) Keep up the awesome stuff, you inspire alot of people to take up particle physics, mathematics, etc. through your videos.
Great video, a very clear way to explain the systems we have to use. Although as one of my 1st year students pointed out to me before. The pendulum does slow down.
It means that your brain is attempting to move backwards in time by organizing information, while the universe is moving forwards in time by disorganizing that which began in an organized state. We are trying to remember what the universe has forgot.
Really nice question!. However, as time is basically interaction, if nothing occurs before the big bang then there is no change in space. If there is no change in space, then as spacetime is inextricably linked, there will be no change in time, and thus no direction to it.
Andrew Tofelt Was that in Hitchhikers? It does sound like Adams. That expression has been used a lot on Doctor Who. I think the first mention was with the introduction of the Weeping Angels.
Except it isn't. You can measure time, it can be defined by other physical quantities, and you can measure its effects on objects. It is antithetical to metaphysics.
Stop with your nonsense word plays, there are no measurements within metaphysics, there is with time; there's a huge distinction between the two. So yes, I suggest you stop repeating idiocy without conscious consideration of what you're saying.
As about 12 people have mentioned before me, Sean's voice is great. The topic/discussion was great too, but there are lots of those on this channel. Sean's voice stands out notably.
I don't believe in an 'arrow of time'. I believe that time is just like space, it has no natural direction in which it progresses. The arrow of time I think is an illusion created by the fact that we remember our past and not our future. This gives us the illusion that we are progressing in time and essentially moving from our birth to our death at a fixed rate. This rate would be the speed at which our brains process information and turn the information into short-term memories. I believe that all our versions are existing and real, just as real as a third spacial dimension is compared to the second. Only those versions have different memories which makes each version think it is progressing in time. This is a really interesting way of looking at the difference between the world the way perceive it and the world the way it actually is, with 4 dimensions rather than 3 dimension of space and 1 progressive time dimension.
There is still the question: what is it about that fourth dimention that make any given version of us remember things only in one direction and not the other?
+Ariel Rile Well, quite. The comment seems to be saying "I believe the arrow of time is an illusion caused by the fact that the past and the future are different". It's a bit like saying you believe gravity is an illusion caused by the curvature of spacetime.
I'm another 3+1 dissenter who believes time isn't unique amongst the dimensions. I'm not with you on the many-worlds interpretation, but I'll help you make your case for 4 dimensional space... Let's start without a reference frame. It is impossible to say how fast objectX is going, the rate of its clock, how compressed it is in any of the spatial dimensions, or its mass. But, objectX has itself as a reference frame. We can now say objectX has no movement in space, its clock runs at full speed, it's uncompressed in all dimensions, and has mass of X. Pick any other reference frame, and things start to change... The subset of possible reference frames that see objectX as moving arbitrarily close to c is still infinite in number. The universal constant is a ratio of space to time, but thinking of it as a speed gets the numbers right, but misses the point. It's a ratio of equivalence. One second=186000 miles
Covalence Dust radioactive decay is and example of single time direction. They never gain neutrons. The basic cycle from H to the heavier elements shows the natural world we exist in is omnidirectional.
Very Interesting video, as usual from sixtysymbols, thank you! It did however somewhat strike me as odd to say that Aristoteles didn't give time much thought, when in fact his fourth book has four chapters devoted to time. Sure they were not the last words on the subject, but there were some serious philosophical fundamentals laid there.
I really dig Dr. Carroll! I could listen to him talk about physics for hours (and have thanks to a number of talks available on RUclips!). Make sure Brady you corner him every chance you can get! And keep up the excellent work. I would like to see more 60 symbols videos (as much as I like Numberphile I love me some physics...)
Great video! The most awesome is the idea of comparing time and space - "space has `arrows` when near a big body" and "time has `arrows` when near a big event"
"air molecules" apart, i get really excited when i watch this kind of video! Its awesome beacuse It not only teaches us how the universe works, but give us something to thing about. But, if you allow me, Brady, for most of the topics covered in your videos, 10 minutes is not enough. As Derek, from Veritasium2, said in his last video: "...there are things that get better just by lasting longer."
No problem. The point to take home is that, other than our own memories, entropy defines events that have occurred earlier with events that have occurred later. If you look at two different photos of the same event, the one with higher entropy can safely be assumed to have taken place later in time, such as a glass of water occurring later than a glass of ice, a slower pendulum occurring later than a faster pendulum, etc.
In the video "Relativity Paradox" on this account, simultaneous events can occur at different times. If the trainspotter was on the end closest to the entrance then the train would first see the guillotine come down, and then see them press the button after the train was through. By changing your momentum you can alter time in the area around you as well, until you stop accelerating and move at a constant speed.
I said his way of asking questions, not that he asks questions. How does being duped even come into it. He's always interviewing an expert in the field being discussed who is considerably more intelligent than himself, and the viewers for that matter. I'm glad he asks questions and the content of the questions is bang on, but I think they should be asked with a lot more politeness and respect. These people being interviewed are giving up their time for free to help him make videos.
For some reason RUclips is not letting me reply to the comment you recently left on my video about Many Words. Thanks for your comment. I have not read the book you mentioned, but I have seen many videos by Deutch--I'll look into it.
To me the fundamental question that arises from think about "directioning" time is: if there was a perfect mathemaical simulation that would take into consideration every single interaction in the universe and knew the exact state of every planck volume in terms of every property that it could have, could it create a physically possible state of the universe. If it could create a future state but not the past state then there actually would be a "preferred" time direction. To a classical physicist it was obvious that any process considered backwards in time could be simulated just by taking a certain state, reversing every vectoral property and watching changes over time. i know that the truth is way more complicated because of shrodinger cats, perfectly random processes, uncertainty laws. Unfortunately as a high school student i'm yet to discover the wonders of modern quantum physics so thinking about them, not even in scientific, but more phylosophycal manner leaves alot of questions unanswerd. to I'm sorry for any grammar or spelling mistakes. English is not my native language.
Consider this. When spacetime is represented as a flat(ish) sheet or on the big scale, as the surface of an expanding balloon....the direction at right angles to the surface is time. The surface moves upward along the time direction, but all we can see is along the horizontal surface. Now near a massive object, the surface (our 3D space) curves down in a funnel toward an earlier time (dilation). Near an event horizon....that surface approaches a down angle (i.e a retardation of time slightly toward the past and thus slower time progression) of 45 degrees. The normally horizontal surface of space has re-angled itself to nearer the vertical direction of time. This model suggests to me....that time is not any different to our 3 spacial directions...but just perpendicular to them....hence a spacial direction literally becomes a time direction when warped into a gravity well. Further....the cosmological arrow of time is no more than the space representing surface expanding out from a single point. Hence in the beginning, space (our spherical surface) was zero when time (the temporal distance of that surface from the origin) was also zero. Time is the literal radius of the (4D) Universe. This model....especially if animated on screen....combines the ideas of world line models with the 45degree light cone model with the space as a growing spherical surface when shown in 2D plus 1 extra D of time. I have yet to see ideas which run counter to it....
The arrow of time has bothered me for years, because it appears to put pure quantum physics (where entropy is always zero) directly at odds with thermodynamics (where entropy always increases), but that was the best explanation I've ever heard of it. If we don't trace out particles from the system (i.e. if we "knew" everything), the entropy would still be zero; we just happened to start in a state where tracing particles out didn't provide much entropy, and it naturally tends away from that.
Sean Carroll might seem a little bit like a know-it-all, with no intention of offence on my part, but he speaks with such a pedagogical voice, and with such clarity, that I can type this comment, watch the video at the same time and still understand everything that has yet been said in the video. I'll keep watching now.
Something about the way this guy communicates things makes me want to hear more from him. He could commentate over the drying of paint for 6 hours and I'd watch it.
I've heard an explanation for the arrow of time that goes something like this: You can only observe increasing entropy because increasing entropy is the only way to disseminate energy that can be observed. It may be that time goes in both directions simultaneously, but we are unable to observe the reverse evolution of the universe. If you were to reverse the scrambling egg, you'd have to reverse the molecules that formed the memory of the egg ever being scrambled in the first place.
Objectively, I don't think Professor Sean Carroll is any better (,or worse than the others of the professors, although all are GREAT,) than the other professors here at sixtysymbols, but I feel that somehow, his slightly deeper voice and casual way of talking conveys a greater meaning of facts. Again, I'm not questioning the skill, nor knowledge, of other professors, but... aww man, I just enjoy hearing him talk. Unless you have a factual objection, please don't correct me. Have a nice day. :)
Time can move in any direction. It's not a question of "which way it's going," but rather where the system is going, what direction force is being applied, where heat is being released, so on. He did say what direction it's going in - toward entropy. And I believe it was an analogy, the astronaut - and a 'relatively' good one.
Not claming that the directionality of time is not a reality, but we can "remember" future events in ways of planning and anticipation. And that way future possibilities are affecting our current state. Stating that, bare in mind that the memories of our past are also affected by anticipating and planning and are not stable. I'm not exactly sure why I say that, but I think it's just valuable to consider this psychological interconnectedness of future and past
Continue to: Time is an abstract that represent movement in space. Each movement of an object* is a reaction to interaction with a force, and each interaction of an object change one or more property of that object, we can look at entropy as an experience point on an object. * An Object can be the collection of objects or the single object. That said, a collection of objects can hold varied level of entropy.
A proton travelling backwards in time would still have a positive charge, it's +1 charge comes from the sum of charges of the two up quarks and a down quark that make up the proton, the fact that it's travelling backwards through time doesn't necessarily convert the quarks to anti-quarks. Just my guess, but you might want to check that up, it's a good question :D
I don't think that both directions of time are equal because of entropy. A simple Newtonian system may have no directionality but a complex system does due to increasing entropy. The universe as a whole is a complex system. That means that it does have a directionality because entropy increases
Well, even entropy will fade though. Think of when the universe expands past stars being able to form, and the last star burns out. Then reaches a point where the universe is so big and the atoms are so spread out they won't interact anymore entropy has been decreasing.
Isn't that what this video just explained, except that you left out the part where you need a low entropy state for entropy to increase from? +illusion z That's not decreasing entropy though. The universe spreading out and becoming perfectly uniform *is* a high entropy state.
I have a question for those knowledgeable on physics, specifically on quantum mechanics. Is time perceived as an oscillating wave, in which space is the linear regression of time? The reason is say space is the linear regression of time is because, from what I know, time determines what will occur next in space, but space does not determine what will occur next in time; hence, the idea that time has "authority" over space. I'm sorry I couldn't simplify this any more.
The Law of Conservation of Energy puts a lot of rational consideration toward the initial, low-entropy levels of our early Universe. Before inception, no energy was being transferred - you could call the 'time' before that event a Universal Ground State. There were no systems in place to attain to the Second Law of thermodynamics yet, yielding no entropy. It increased as systems were introduced. Brady, you're right about a lot of the questions you ask. Many of our assertions hinge on semantics.
@sixtysymbols, I think you guys should have an online physics/mathy competition for those aspiring physicists(myself included) to win a trip to view Nottingham and meet the professors! or just a prize or something, but that would be really cool.
Another related question I have been wondering about: a lot of scientist say that the universe is infinite in the spacial dimensions, while the dimension of time is finite (big bang till what ever ends it). So why can those three dimensions be infinite while time is limited? Or is that just the illusion created by macroscopic entropy, and we just can't observe beyond the low entropic origin?
I'd like to address entropy (order/disorder). As an alternate view, I'd like to suggest stable/unstable. Order/disorder is rather subjective/opinionated. Stable/unstable is more objective/measurable. Unstable is a form of order that needs some maintenance to sustain it. Stable is just another form of order requiring less maintenance. It's all relative. It changes form, not beauty.
Dr. Carroll has a *very* camera-friendly personality, I would love to see more videos with him explaining stuff :D You should definitely take the camera if you get to see him again - and tell him youtube says hi ;)
I recently read his book "From Eternity to Here". It's really, really interesting, and if you have any sort of questions about this stuff it's the one book you need to read.
I just find it so interesting that even the most involved theorists and philosophers etc in the end choose to live their lives as we've always done. It's the greatness of everyday life :)
Of all the people featured here, Sean Carroll is one of the best at communicating clearly and precisely.
trefod It's not really a fair comparison because the others are teachers so they aren't really used to trying to explain new information to people.
Jacob Estes Oh You! :D
+trefod I wish Richard Feymann was still alive and taught me physics
+ray lin That must be on the wish list of almost all sixty symbols viewers. I know it's on mine too.
+trefod I agree. I enjoy listening to him.
The fluency and clearness in they way he talks is perfect.It makes those who don't have a physics background help get a grasps on these fundamental ideas. As can be said about all the other talkers on sixtysymbols, and Brady's other channels. Bravo.
I love how Brody keeps asking the right questions thus leading into a more interesting video
Hes such a great communicator
I love this guy, please do more with him!
I want this guy as my prof, I could listen to him for hours, his voice is so soothing lol
+xToTaLBoReDoMx it is possible, if you join Caltech as a student.
❤
Who the hell scrambles an egg with the shell still in
DarkLordGiggles Some working physicists, who think too much:)
haven't you heard? it's more organic!!!
australians
HowtoBasic
@Dark People that believe they can unscramble it.
Brady, I love what you have done for us here with all these channels. I don't think I've ever learned as much as when you interview these brilliant people. And your way of asking questions just shows what a great view of life you have and how you really burn for these types of questions.
These channels are my go-to place whenever I need a thoughtnugget, thank you so much for doing this for us!
There's loads coming out this week across my channels!
Never stop
Please tell Sean that he needs to narrate a documentary at some point in his life. He is so good at explaining things and I could easily listen to his voice all day!
Liked for teaching me the word "retrodicting."
Yesterday, Sixty Symbols taught me "countervailing"
I like this guy. He explains things very well and is enjoyable to listen to. Please include him in more videos.
The arrow of time sounds like something you'd find in a treasure chest in a Zelda game
I love the explanation. Also I love the equations on the board in the background. Details like that can make one feel a lot better, and contribute to a video's quality.
He reminds me of James Woods. Wish I had a physics professor like him at university...
Thomace22 he really does.
I could listen to Mr. Carroll talk for hours. His mannerisms, speech patterns and inflections make him very interesting to listen to, while his explanations are well articulated for folks who haven't a clue what he's on about going in. He makes complex subjects easy to listen too, and hopefully learn a little from.
"goes up and and down".. funny face realizing that his hand went in the other order.. "I should say down and up" LOL
Stunning line of arguments.
mentions breaking an egg and scrambling it
dumps whole egg in a bowl and tries to beat it
What makes these videos damn awesome is the fact that Brady always asks the questions the rest of us are thinking about. That's why I love these videos and think that these are more educational than many straight up explanation or teaching videos of the same topics.
great to hear - thx
Sixty Symbols Nice video
Brady, you do a really great job editing these videos. Enjoyable to watch.
I left a glass of water on my bedside table last night and when i woke up there was ice cubes in it. Forgot to say I went to sleep outside at the south pole...
How did it break into cubes though? =O
How did that happen?!
I gotta look that up in that case! In the few videos he has been in on sixty symbols he's starting to become one of my favorite "stars". The way he explains things is extremely clear and always spot on. Enough detail to keep it relevant and correct, but simplified enough so us normal people can understand it in one go.
Quite honestly I'm baffled after every video with him in it. Such a smart and inspiring man to listen to.
Entropy is not what it was.
Chaos is a granularity error.
The definition has become 'messier'
It just complicates matters.
Literally.
what an incredibly enriching chat! this channel is a goldmine for the mind, this should also find itself featured on the front page of youtube alongside of all the banal content.
Time flies like an arrow. Fruit flies like banana.
I remember reading that in Omni magazine .. "roses are red violets are blue, space is warped and so are you"
Like the frogs say "Times fun when your having flies"
nice copy and paste..
Really enjoy the videos you've made with this guy Brady. He explains things very clearly and in a lot of depth and his analogies are so insightful.
Time flies like an arrows, fruit flies like a banana . :D
I really love this guy. To me he has a incredibly good interpretation of "things".
The Jack Bauer of Science.
By the way, thanks for being probably the most insightful and broad-ranging youtuber there is :) Keep up the awesome stuff, you inspire alot of people to take up particle physics, mathematics, etc. through your videos.
I thought he was talking about One Direction
Great video, a very clear way to explain the systems we have to use. Although as one of my 1st year students pointed out to me before. The pendulum does slow down.
8:13 interviewer- time rules your life.. the guy- no one rules my life..(say one more word and imma punch you in the face!!)
just realized this is the guy that does some of the best pieces of work for the great courses. if you have audible its a must buy
Does that mean the time on the other "side" of the big bang has an arrow of time going away from us? :D
What do you mean with "the other side of the Big Bang"?
Duh, dimensional theories, it's like an anti-bigbang supposedly going back-timed (for that universe it's forward-- or something I DONT KNOW)
It means that your brain is attempting to move backwards in time by organizing information, while the universe is moving forwards in time by disorganizing that which began in an organized state. We are trying to remember what the universe has forgot.
Really nice question!. However, as time is basically interaction, if nothing occurs before the big bang then there is no change in space. If there is no change in space, then as spacetime is inextricably linked, there will be no change in time, and thus no direction to it.
There are some interesting discussions about that topic
"Retrodicting"! A wonderful word that I hadn't come across before. Thanks for that.
Excuse me, but I remember what happens tomorrow p.o
I uh... eat cereal.
And do stuff... Yes.
"our universe started in a state of exquisite order" solid quote right there
Has he ever thought that maybe it could be a big ball of wibbly wobbly timey wimey stuff?
+1 for Hitchhiker's reference. Douglas Adams was awesome.
Andrew Tofelt
Was that in Hitchhikers? It does sound like Adams.
That expression has been used a lot on Doctor Who. I think the first mention was with the introduction of the Weeping Angels.
time in our universe is one dimensional, so unfortunately that reference is false
This guy is excellent with... everything relating to what this channel tries to achieve.
Time seems to be as physical as it does metaphysical..
Except it isn't. You can measure time, it can be defined by other physical quantities, and you can measure its effects on objects. It is antithetical to metaphysics.
Stop with your nonsense word plays, there are no measurements within metaphysics, there is with time; there's a huge distinction between the two. So yes, I suggest you stop repeating idiocy without conscious consideration of what you're saying.
As about 12 people have mentioned before me, Sean's voice is great.
The topic/discussion was great too, but there are lots of those on this channel. Sean's voice stands out notably.
I don't believe in an 'arrow of time'. I believe that time is just like space, it has no natural direction in which it progresses. The arrow of time I think is an illusion created by the fact that we remember our past and not our future. This gives us the illusion that we are progressing in time and essentially moving from our birth to our death at a fixed rate. This rate would be the speed at which our brains process information and turn the information into short-term memories. I believe that all our versions are existing and real, just as real as a third spacial dimension is compared to the second. Only those versions have different memories which makes each version think it is progressing in time. This is a really interesting way of looking at the difference between the world the way perceive it and the world the way it actually is, with 4 dimensions rather than 3 dimension of space and 1 progressive time dimension.
There is still the question: what is it about that fourth dimention that make any given version of us remember things only in one direction and not the other?
+Ariel Rile Well, quite. The comment seems to be saying "I believe the arrow of time is an illusion caused by the fact that the past and the future are different". It's a bit like saying you believe gravity is an illusion caused by the curvature of spacetime.
So basically, quackery?
I'm another 3+1 dissenter who believes time isn't unique amongst the dimensions. I'm not with you on the many-worlds interpretation, but I'll help you make your case for 4 dimensional space...
Let's start without a reference frame. It is impossible to say how fast objectX is going, the rate of its clock, how compressed it is in any of the spatial dimensions, or its mass. But, objectX has itself as a reference frame. We can now say objectX has no movement in space, its clock runs at full speed, it's uncompressed in all dimensions, and has mass of X. Pick any other reference frame, and things start to change... The subset of possible reference frames that see objectX as moving arbitrarily close to c is still infinite in number.
The universal constant is a ratio of space to time, but thinking of it as a speed gets the numbers right, but misses the point. It's a ratio of equivalence.
One second=186000 miles
Covalence Dust radioactive decay is and example of single time direction. They never gain neutrons. The basic cycle from H to the heavier elements shows the natural world we exist in is omnidirectional.
Congratulation to Brady and Dr. Sean Carroll for the great video! It was such a good conversation! Thank you very much
This channel is regularly blowing my mind. Thinking of time as a similar function of gravity just turned my views upside down.
I love Sean Carroll and I love Sixty Symbols! How did I miss this one.
Very Interesting video, as usual from sixtysymbols, thank you! It did however somewhat strike me as odd to say that Aristoteles didn't give time much thought, when in fact his fourth book has four chapters devoted to time. Sure they were not the last words on the subject, but there were some serious philosophical fundamentals laid there.
He's got a good voice and style for this kind of thing. Very clear and engaging.
I really dig Dr. Carroll! I could listen to him talk about physics for hours (and have thanks to a number of talks available on RUclips!). Make sure Brady you corner him every chance you can get!
And keep up the excellent work. I would like to see more 60 symbols videos (as much as I like Numberphile I love me some physics...)
Great video!
The most awesome is the idea of comparing time and space - "space has `arrows` when near a big body" and "time has `arrows` when near a big event"
"air molecules" apart, i get really excited when i watch this kind of video! Its awesome beacuse It not only teaches us how the universe works, but give us something to thing about.
But, if you allow me, Brady, for most of the topics covered in your videos, 10 minutes is not enough. As Derek, from Veritasium2, said in his last video: "...there are things that get better just by lasting longer."
No problem. The point to take home is that, other than our own memories, entropy defines events that have occurred earlier with events that have occurred later. If you look at two different photos of the same event, the one with higher entropy can safely be assumed to have taken place later in time, such as a glass of water occurring later than a glass of ice, a slower pendulum occurring later than a faster pendulum, etc.
So many Brady Haran videos released in one day. Today is a good day! :-)
In the video "Relativity Paradox" on this account, simultaneous events can occur at different times. If the trainspotter was on the end closest to the entrance then the train would first see the guillotine come down, and then see them press the button after the train was through.
By changing your momentum you can alter time in the area around you as well, until you stop accelerating and move at a constant speed.
Love this guy's voice. I could just listen to him talk physics all day.
I like the way he talks - very clear and concise.
I said his way of asking questions, not that he asks questions. How does being duped even come into it. He's always interviewing an expert in the field being discussed who is considerably more intelligent than himself, and the viewers for that matter. I'm glad he asks questions and the content of the questions is bang on, but I think they should be asked with a lot more politeness and respect. These people being interviewed are giving up their time for free to help him make videos.
Excellent video! I would like to see more of this professor!
For some reason RUclips is not letting me reply to the comment you recently left on my video about Many Words. Thanks for your comment. I have not read the book you mentioned, but I have seen many videos by Deutch--I'll look into it.
To me the fundamental question that arises from think about "directioning" time is: if there was a perfect mathemaical simulation that would take into consideration every single interaction in the universe and knew the exact state of every planck volume in terms of every property that it could have, could it create a physically possible state of the universe. If it could create a future state but not the past state then there actually would be a "preferred" time direction. To a classical physicist it was obvious that any process considered backwards in time could be simulated just by taking a certain state, reversing every vectoral property and watching changes over time. i know that the truth is way more complicated because of shrodinger cats, perfectly random processes, uncertainty laws. Unfortunately as a high school student i'm yet to discover the wonders of modern quantum physics so thinking about them, not even in scientific, but more phylosophycal manner leaves alot of questions unanswerd. to I'm sorry for any grammar or spelling mistakes. English is not my native language.
Consider this. When spacetime is represented as a flat(ish) sheet or on the big scale, as the surface of an expanding balloon....the direction at right angles to the surface is time. The surface moves upward along the time direction, but all we can see is along the horizontal surface. Now near a massive object, the surface (our 3D space) curves down in a funnel toward an earlier time (dilation). Near an event horizon....that surface approaches a down angle (i.e a retardation of time slightly toward the past and thus slower time progression) of 45 degrees. The normally horizontal surface of space has re-angled itself to nearer the vertical direction of time. This model suggests to me....that time is not any different to our 3 spacial directions...but just perpendicular to them....hence a spacial direction literally becomes a time direction when warped into a gravity well. Further....the cosmological arrow of time is no more than the space representing surface expanding out from a single point. Hence in the beginning, space (our spherical surface) was zero when time (the temporal distance of that surface from the origin) was also zero. Time is the literal radius of the (4D) Universe. This model....especially if animated on screen....combines the ideas of world line models with the 45degree light cone model with the space as a growing spherical surface when shown in 2D plus 1 extra D of time. I have yet to see ideas which run counter to it....
I have no more filmed, but if I get to see him again I'll bring my camera!
Finally! I was afraid you had given up on sixtysymbols. Thanks, Brady, once more you saved Townsville.
New Computerphile, Numberphile, and Sixty Symbols videos within a week. I think my head just exploded!
I really liked this episode.
This is the kind of thing I like to learn or hear about.
The arrow of time has bothered me for years, because it appears to put pure quantum physics (where entropy is always zero) directly at odds with thermodynamics (where entropy always increases), but that was the best explanation I've ever heard of it. If we don't trace out particles from the system (i.e. if we "knew" everything), the entropy would still be zero; we just happened to start in a state where tracing particles out didn't provide much entropy, and it naturally tends away from that.
Check the Sixty Symbols website!
Sean Carroll might seem a little bit like a know-it-all, with no intention of offence on my part, but he speaks with such a pedagogical voice, and with such clarity, that I can type this comment, watch the video at the same time and still understand everything that has yet been said in the video. I'll keep watching now.
He's a great speaker. Who knew you could take such a wibbly-wobbly concept of the arrow of time and make it sound so logical?
Something about the way this guy communicates things makes me want to hear more from him. He could commentate over the drying of paint for 6 hours and I'd watch it.
I've heard an explanation for the arrow of time that goes something like this: You can only observe increasing entropy because increasing entropy is the only way to disseminate energy that can be observed. It may be that time goes in both directions simultaneously, but we are unable to observe the reverse evolution of the universe. If you were to reverse the scrambling egg, you'd have to reverse the molecules that formed the memory of the egg ever being scrambled in the first place.
I've heard this explained before, but not quite as well. Thanks Brady and Sean!
They aren't scripted - but I am a viewer listening just like you, so I guess it is natural I'll ask what you would ask!?
I quite enjoy these videos with Dr. Carroll, do you have plans for any others?
By the way, I think you explained this topic marvelously. Congratulations!
this channel is heaven. thanks.
Objectively, I don't think Professor Sean Carroll is any better (,or worse than the others of the professors, although all are GREAT,) than the other professors here at sixtysymbols, but I feel that somehow, his slightly deeper voice and casual way of talking conveys a greater meaning of facts. Again, I'm not questioning the skill, nor knowledge, of other professors, but... aww man, I just enjoy hearing him talk.
Unless you have a factual objection, please don't correct me. Have a nice day. :)
his voice is very pleasing, it is easy listening to him
Are the questions scripted? They are so well formulated and seem to always speak to the interests of the viewers. Quite a talent either way.
Time can move in any direction. It's not a question of "which way it's going," but rather where the system is going, what direction force is being applied, where heat is being released, so on. He did say what direction it's going in - toward entropy. And I believe it was an analogy, the astronaut - and a 'relatively' good one.
Not claming that the directionality of time is not a reality, but we can "remember" future events in ways of planning and anticipation. And that way future possibilities are affecting our current state. Stating that, bare in mind that the memories of our past are also affected by anticipating and planning and are not stable. I'm not exactly sure why I say that, but I think it's just valuable to consider this psychological interconnectedness of future and past
Continue to: Time is an abstract that represent movement in space.
Each movement of an object* is a reaction to interaction with a force, and each interaction of an object change one or more property of that object, we can look at entropy as an experience point on an object.
* An Object can be the collection of objects or the single object.
That said, a collection of objects can hold varied level of entropy.
I enjoy his voice and how he formulates what he says.
Could someone please explain the word "entropy" in an easy way?
I've just looked it up but I still don't get it...
A proton travelling backwards in time would still have a positive charge, it's +1 charge comes from the sum of charges of the two up quarks and a down quark that make up the proton, the fact that it's travelling backwards through time doesn't necessarily convert the quarks to anti-quarks. Just my guess, but you might want to check that up, it's a good question :D
I don't think that both directions of time are equal because of entropy. A simple Newtonian system may have no directionality but a complex system does due to increasing entropy. The universe as a whole is a complex system. That means that it does have a directionality because entropy increases
Well, even entropy will fade though. Think of when the universe expands past stars being able to form, and the last star burns out. Then reaches a point where the universe is so big and the atoms are so spread out they won't interact anymore entropy has been decreasing.
Isn't that what this video just explained, except that you left out the part where you need a low entropy state for entropy to increase from?
+illusion z That's not decreasing entropy though. The universe spreading out and becoming perfectly uniform *is* a high entropy state.
I have a question for those knowledgeable on physics, specifically on quantum mechanics. Is time perceived as an oscillating wave, in which space is the linear regression of time? The reason is say space is the linear regression of time is because, from what I know, time determines what will occur next in space, but space does not determine what will occur next in time; hence, the idea that time has "authority" over space. I'm sorry I couldn't simplify this any more.
Sean Carroll videos are always good :) more of that !
I could listen to these guys ALL F**KING DAY and still not get bored haha thanks Brady keep me coming! I need to stay sane haha
The Law of Conservation of Energy puts a lot of rational consideration toward the initial, low-entropy levels of our early Universe. Before inception, no energy was being transferred - you could call the 'time' before that event a Universal Ground State. There were no systems in place to attain to the Second Law of thermodynamics yet, yielding no entropy. It increased as systems were introduced.
Brady, you're right about a lot of the questions you ask. Many of our assertions hinge on semantics.
Finally! I was waiting for this since january.
@sixtysymbols, I think you guys should have an online physics/mathy competition for those aspiring physicists(myself included) to win a trip to view Nottingham and meet the professors! or just a prize or something, but that would be really cool.
Another related question I have been wondering about: a lot of scientist say that the universe is infinite in the spacial dimensions, while the dimension of time is finite (big bang till what ever ends it). So why can those three dimensions be infinite while time is limited? Or is that just the illusion created by macroscopic entropy, and we just can't observe beyond the low entropic origin?
I'd like to address entropy (order/disorder). As an alternate view, I'd like to suggest stable/unstable. Order/disorder is rather subjective/opinionated. Stable/unstable is more objective/measurable. Unstable is a form of order that needs some maintenance to sustain it. Stable is just another form of order requiring less maintenance. It's all relative. It changes form, not beauty.
Dr. Carroll has a *very* camera-friendly personality, I would love to see more videos with him explaining stuff :D
You should definitely take the camera if you get to see him again - and tell him youtube says hi ;)
I recently read his book "From Eternity to Here". It's really, really interesting, and if you have any sort of questions about this stuff it's the one book you need to read.
I just find it so interesting that even the most involved theorists and philosophers etc in the end choose to live their lives as we've always done. It's the greatness of everyday life :)
Truly excellent explanation. This man is a fantastic teacher.