Some people's personalities just...shine. Or rather, they shine through. One only has to watch Sean Carroll for a little while to know, to a high degree of certainty, that he is not only highly intelligent, but also that he has a wonderful wit, is a kind human being, is fundamentally optimistic, and is thoroughly unpretentious. Thanks so much for creating this series Dr. Carroll.
D'accord! Kind words. I feel glad, I discovered his chanel. I have a minor in Physics and appreciate very much, he does not shy away to use and explain formulas.
@@jonathanwalther I just watched this but missed how the conservation of energy led to... where did it lead to? And did he explain what the idea of a spherical cow was?
Sean, please keep doing this! You truly have a gift. Love your work and your passion for educating the uninitiated. I'm 36 and deeply regret not taking physics more seriously growing up. Your lectures and videos are such a source of intellectual nourishment for me. I am a regular listener of your Mindscape podcast and a Patreon supporter. Please keep producing more work that benefits people like me who are not trained in the math but are curious about the big questions nonetheless. Cheers! Please stay safe!
I believe 'momentum' is a measure of the effect of motion that we observe around us. This is a more intuitive way of understanding the physical meaning of momentum. Great work Sean ! 😊😊
As a non-native English speaker, I find Sean Caroll speaks one of the most understandable and agreable English I've heard from English people. Robert Eagle from Dr. Physics A channel is also very understandable and agreable. Why all English people are not physics specialists ?
Pro tip: I don't know what you are using for video editing but somewhere you should be able to adjust the colours. Lower the green values, maybe cyan. That's an easy way to clean up the edges and even the light scatter. Greetings from Germany, keep it up!
Leave questions here, over the next couple of days I'll pick some favorites and try to answer them in a separate video. (Not "ask me anything," but "ask me about stuff discussed in the video.")
First, is this an accurate statement ? - Dark energy causes the acceleration of the space-time fabric which leads to the expansion of the universe. Second - Does the motion induced by dark energy obey the conservation of momentum ?
@@jeffwatson9868 Yes, in special relativity the momentum 4-vector is conserved, meaning the local change in time of its spacial density is compensated by the flow of momentum current in every other direction. You may as well think of the change in time of the momentum spacial density, as the flow of the momentum current in the "time" direction. This conservation is applied, in a given frame of reference, to each component of the 4-vector independently. You may think of the "time" component of the momentum as energy. General relativity does not change this.
Is there a point at which physicists might come to a consensus about, physics as a field being complete ,meaning there will be no more improvements required.what should such a theory ought to explain to consider the field complete in your opinion.
Very happy to have found Sean’s channel. Usually I need to watch channels that have less information (colloquial sense) and have about 1037490174x more ads so see him.
Here's an unnecessary comment, but anyway... Sean, I don't subscribe to many worlds, I don't like some of your politics, you have a rather (passively) antagonistic relationship with a public intellectual I greatly admire - all things that in this day and age could be a turn off to engaging with someone BUT you really are the best, and perhaps most honest, public educator of difficult physics topics around right now. Thank-you for this series and your contribution to public science education.
Dude, I am 62 years old... wish back in the day I had you (if I could go back in time and you stayed the same young age your are now) as a professor. You rock! Make things understandable to most. Love the Quantum info too!! Please do more. - Tom from Skokie, IL
Great work sean, thank you for taking time to make these podcasts. And for educating this generation and hopefully future generations to come, thanks from Ireland ☘
Thank you for doing your part explaining complex topics and making your mark on the internet. In the information age, this will live on forever and in the future you may even be regarded as a modern Aristotle-type thinker from the 21st century. Cogito, ergo sum.
It’s some 20 years ago I learned Newtonian mechanics and conservative of momentum. Physics still fascinates me despite I have left the field for more than 10 years by now. Thanks for the series. I wish this existed when I started out in my physics training. Maybe I will show this to my children one day. My eldest is 7.
Dr. Caroll, thank you so much for your podcast, books and your UA-cam channel. Love your work and thank you for being such an incredible communicator of science. All the very best to you and your family.
I reckon you could write a book from these talks. You are so good at explaining these concepts that I think if it was in book form you could reach a wider audience.
The idea of the spherical cow and its implications (as you have explained) should be explained in the first lecture in every middle and high school. In my experience students do not see the connection between the simplified physics they learn in class and the real physics they experience on a daily basis. This makes it hard for them to really appreciate the importance of the subject of physics to their life. Thanks for talking about it.
I rarely ever comment on anything on youtube, but I just wanted to let you know that i LOVE listening to you. I think NDT gets a ton of admiration and praise (rightfully so) for being the best at teaching/discussing REALLY intelligent ideas to the basic public in a way that is fun, desirable and educational. But you make me yearn for more, you make it SO exciting and so easy to develop a desire to want to understand more about physics. You and Brian Greene are my hero's! I think i may have chosen the wrong field for my career! :( #iwannabeaphysicists.
What is your field? I know, I'm 2 years late, but anyway... It's almost never too late to learn something new. Cheers. (btw: sorry for nitpicking, but "heros" is plural and thus without an apostrophe)
With regards to Noether's theorem (1915), if we want to be more specific and inclusive, Emmy Noether was not the first person to discover the fundamental link between symmetries and conserved currents (energy, momentum, angular momentum, etc.). Many people in the physics community ignore this fact, but the intimate connection between symmetries and conservation laws was first noticed in classical mechanics by Jacobi in 1842. In his paper, Jacobi showed that for systems describable by a classical Lagrangian, invariance of the Lagrangian under translations implies that linear momentum is conserved, and invariance under rotations implies that angular momentum is conserved. Still later, Ignaz Robert Schütz (1897) derived the principle of conservation of energy from the invariance of the Lagrangian under time translations. Gustav Herglotz (1911) was the first to give a complete discussion of the constants of motion assiciated with the invariance of the Lagrangian under the group of inhomogeneous Lorentz transformations. Herglotz also showed that the Lorentz transformations correspond to hyperbolic motions in R3. What Noether did, was to put every case into the generalized and firm framework of a mathematical theorem
What an amazing approachable lecture On a topic that unless someone maintained math physics and other acumen would potentially be in an accessible for the didactic approach teaching often takes I think about these things all the time life does not allow me to return to first principles and what a wonderful alternative to still feel like you can understand concepts when a good teacher appears Having done high school and university level physics only I can tell this series of videos is going to be extremely enjoyable inspiring and possibly very educational Apart from my own enjoyment I am certain there will be people who will be motivated in either direction to the didactics and first principles or to be inspired and some other way Thank you for this
Kinetic energy is momentum in the TIME direction (the "ct" fourth dimension in Einstein's Relativity formulae). This was how he found the "E = m x c-squared)" relationship.
Thanks for this. I've always found Physics to be far more relateable (and interesting) by really going into Friction, Drag, etc. first. There are many everyday experiments you can do; dropping balls in honey, vs water vs air, sliding blocks on ice vs wood planes, etc. These reinforce a sense of exploration. Instead, we usu start with Galileo, and go right to frictionless planes and perfect collisions, without directly replicating that journey. Students hear it as i.e. "accept the enlightenment of the experts and you will understand" which is very anti-science. Only in college do we finally fill in those missing blocks and it all becomes real.
Its so funny to see you talking about these concepts because I went through your great courses thing and its funny to see the person not just the voice, you're a great teacher.
(this series is about mathenaticians setting the value of the universe to 1(one) - where they obviously should have set the value of the universe to infinite/infinite acelleration)
Economics definitely uses spherical cows. Here's a joke economics tell each other: A physicist, an engineer and an economist are stranded in the desert. They are hungry. Suddenly, they find a can of corn. They want to open it, but how? The physicist says: “Let’s start a fire and place the can inside the flames. It will explode and then we will all be able to eat”. “Are you crazy?” says the engineer. “All the corn will burn and scatter, and we’ll have nothing. We should use a metal wire, attach it to a base, push it and crack the can open.” “Both of you are wrong!” states the economist. “Where the hell do we find a metal wire in the desert?! The solution is simple: ASSUME we have a can opener”… But you're right in that one of the big tensions in economics is when theory and empiricism clash (e.g., minimum wage) and that's probably not as big of a deal in Physics, where it's much easier to test.
Mark Carroll You are right that econ uses its versions of the spherical cow, much more so than any other social science. Maybe this is how economics managed to become much more quantitative and precise than other social sciences. It has given rise to the criticism of “physics envy” , mainly by non-economists who may in turn envy economists. On a quibble, the debate over minimum wages is actually a good example of the success of the spherical cow. With a perfectly competitive labour market, raising it cuts employment. In a justly famous article Card et al. discovered a case in which this didn’t happen. They didn’t conclude that economics is all wrong, but that there must be something else at work, such as that the smallish local labour market they studied might not be perfectly competitive, in which case raising the minimum wage could raise employment.
A LOT of spherical cows in economics. You beat me to it. Here's a list of some classics - Perfect competition - Representative agent - Rational agent - Time consistent preferences - No arbitrage - Benevolent government - Full information, or at least full information about the probability space - Non-decreasing average costs
Hi Mark, good joke by the way. So i'd say the biggest answers in physics as well as in economics came from exactly the points on which theory and empiricism clash. And they both tell us a story about nature.
I know...there is no stupid question...but there is one I have...IDK (sorry for my bad english) Everything is moving...The Earth is moving...Me is moving....An Atom is moving...Electrons are moving...Protons also....I know, there is quantum movement...even the so called "Nothing" is moving....But is there a state of something , where the Matter is in a rest state? I mean, even we on earth, every Atom is moving...Earth is moving around the Sun...Sun is moving around the Milkyway...Milkyway is moving around the...You know what I mean...Is motion a constant state of matter or is there even a term of a particle that is not in motion?? Is there a Particle somewhere in Universe, somewhere between Galaxies, that does not "feel" gravity or any force and does not move at all...I hope you understand what I mean....I would be very greatful for an answer!!! ♥ :)
Love this! Is it accurate to say that the laws of physics are simply descriptions of very regular patterns in the universe? Is the scientific community essentially looking for and attempting to accurately describe regular patterns? Or have I misunderstood?
" say that the laws of physics are simply descriptions of very regular patterns " - yes, that is the working premise. This is different than the old fashion approach of needing a deity to declare/create rules, or the self-defeating idea that the universe is too random or too hard to be understood (at least in some useful sense.)
Love the video's! When are you doing a new course on TTC? I did follow the " older" counrces but it would be so cool to have the new insights that are there now!
Obsessed with the intellects! Thank you for the lessons, making it accessible to those of us that have no background, the patience involved with this and hitting so many areas the vast majority of us are curious on but had no way of knowing where to start. I crave the day that all ladies understand intellectual power over brute force. These are our lovers, the others are cavemen yuck 🙈🙉
Physics has changed to the same degree that the tools we use to make tools need to be better than the tools we make with them..Also one depends on the written history of others when we make propositions...?
This is just what I was needing while looking at a couple of weeks of self isolation. One thing I wonder about is spin: planets, stars, particles, all spin - could we find a way to determine if the cosmic microwave background radiation is also 'spinning'?
Conservation of momentum does not seem to come into play into the development of statistical mechanics (as defined by Gibbs, 1902). The closest thing I can see is the use of the Hamiltonian Mechanics in the derivation of the canonical ensemble probability formula. What does the conservation of momentum add to the thermodynamic picture?
Is this filmed on a webcam? I know that's not supposed to be the focus of this, but I think you might want to use your smartphone instead. Makes the editing a little trickier if you don't have a good microphone you can connect to it but the video quality will be incomparable and you won't have to invest in a real camera or a lot of cinematography skills because modern smartphone cameras are pretty wild.
I just wondered; when a positron meets an eletcron, they annihilate each other and are turned into energy. But what happens when an anti-nutrino meets a proton?
I have a question: What's the relationship between conservation of energy and conservation of momentum? That is to say, how are they related to each other? For example, I notice that one way to get kinetic energy from momentum is to integrate with respect to velocity, but what does that even mean? How is that interpreted? The best I can do is that changes in energy (with respect to velocity) are caused ny momentum, but I don't think that's quite it and it isn't satisfying at all.
Sean Carroll very much overstates the role of Émilie du Châtelet. Perfectedly understandable of course in this time and age, but historically incorrect. The actual experiments were done by Polleni (see en.wikipedia.org/wiki/Giovanni_Poleni ) and 's-Gravesande (see en.wikipedia.org/wiki/Willem_%27s_Gravesande ). Du Châtelet incorporated their discoveries in the story, no more, no less.
Actually there is a spherical cow concept in economics: it’s the concept of the evenly rotating economy as described by Ludwig von Mises in his book, Human Action.
I have a question regarding how orbiting bodies lose momentum to gravitational waves. Does this imply that even in the vacuum of space, given enough time, an object will slow down and stop (similar to air resistance on earth)?
Hi Sean, thanks for starting for this series and going to the heart of key concepts which generally not taught in the class. For example, why the idea of conservation of momentum is a paradigm shifting idea. I have a question about the Higgs field. Sometimes I have heard that Higgs field is like a molasses or viscous fluid which drags on the particles to give them mass. I can understand this to some extent when one tries to move a particle at rest, the viscosity will resist it hence the inertia. But molasses or viscous fluid will not let a particle to move at constant speed. It will slow it down. That is why I do not like molasses analogy. Instead I like the photon-box analogy for mass. What are your thoughts on this. I try to insist on use of correct analogies with non-physics educated people because it gives wrong impressions if the wrong analogy is used. Thoughts?
Aristotle: One of the great, most profound thinkers of all time. Also Aristotle: Some is pure "bro science" in today's terms. Aristotle's arrow explanation is a great example of Bro science in the Classical Age.
If someones interested in the History of Physics (and can understand German) there is a youtube show called "Von Aristoteles zur Stringtheorie". It´s pretty good.
How old is the spherical cow idea? The Russian version talks about a spherical horse in vacuum (and the story itself is a bit lengthier). I wonder if it was adapted or developed independently.
Did you accidentally mix up inelastic & elastic collisions? You described billiard ball collisions as elastic & silly putty collisions as inelastic. I'd have thought they'd be the other way around... Unless I'm misunderstanding something?
The place we fundamentally disagree is that experience has taught me that Consciousness is more likely a Universal Field than something generated by the brain. The brain is the focal point, not the generator. As shocking as it may sound, the Universe really is alive. I had to abandon Materialism after my third prophetic dream, it simply no longer explained my experiences. But you are exactly who you should be, as am I. Finally.
There is visible light we see. Colors during the day but At nighttime or in a dark room no colors. If you look into the night sky what you see appears black, or is it colorless. Question. What color is space?.
Since we live in a world in which all things are in motion, how do we scientifically test whether there is or is not a force that moves and transforms everything in the universe?
Some people's personalities just...shine. Or rather, they shine through. One only has to watch Sean Carroll for a little while to know, to a high degree of certainty, that he is not only highly intelligent, but also that he has a wonderful wit, is a kind human being, is fundamentally optimistic, and is thoroughly unpretentious. Thanks so much for creating this series Dr. Carroll.
I couldn’t have said it better.
Exactly how I picture him. Thank you !
Totally agree. Jennifer is a lucky woman!
D'accord! Kind words. I feel glad, I discovered his chanel. I have a minor in Physics and appreciate very much, he does not shy away to use and explain formulas.
@@jonathanwalther I just watched this but missed how the conservation of energy led to... where did it lead to? And did he explain what the idea of a spherical cow was?
I love this! Great idea! It's an honor to have you here on UA-cam, Sir.
Sean, please keep doing this! You truly have a gift. Love your work and your passion for educating the uninitiated. I'm 36 and deeply regret not taking physics more seriously growing up. Your lectures and videos are such a source of intellectual nourishment for me.
I am a regular listener of your Mindscape podcast and a Patreon supporter. Please keep producing more work that benefits people like me who are not trained in the math but are curious about the big questions nonetheless. Cheers! Please stay safe!
Hi! How has your voyage into physics been these last four years? Hopefully you are still on your self-directed path of learning!
I believe 'momentum' is a measure of the effect of motion that we observe around us. This is a more intuitive way of understanding the physical meaning of momentum.
Great work Sean ! 😊😊
As a non-native English speaker, I find Sean Caroll speaks one of the most understandable and agreable English I've heard from English people. Robert Eagle from Dr. Physics A channel is also very understandable and agreable. Why all English people are not physics specialists ?
Pro tip: I don't know what you are using for video editing but somewhere you should be able to adjust the colours. Lower the green values, maybe cyan. That's an easy way to clean up the edges and even the light scatter. Greetings from Germany, keep it up!
Leave questions here, over the next couple of days I'll pick some favorites and try to answer them in a separate video. (Not "ask me anything," but "ask me about stuff discussed in the video.")
If time is the currency of life, why should a person specialise and miss out on observation?
Is conservation of momentum also a local notion like conservation of energy, in General Relativity?
First, is this an accurate statement ? - Dark energy causes the acceleration of the space-time fabric which leads to the expansion of the universe.
Second - Does the motion induced by dark energy obey the conservation of momentum ?
@@jeffwatson9868 Yes, in special relativity the momentum 4-vector is conserved, meaning the local change in time of its spacial density is compensated by the flow of momentum current in every other direction. You may as well think of the change in time of the momentum spacial density, as the flow of the momentum current in the "time" direction.
This conservation is applied, in a given frame of reference, to each component of the 4-vector independently. You may think of the "time" component of the momentum as energy.
General relativity does not change this.
Is there a point at which physicists might come to a consensus about, physics as a field being complete ,meaning there will be no more improvements required.what should such a theory ought to explain to consider the field complete in your opinion.
Very happy to have found Sean’s channel. Usually I need to watch channels that have less information (colloquial sense) and have about 1037490174x more ads so see him.
Here's an unnecessary comment, but anyway...
Sean, I don't subscribe to many worlds, I don't like some of your politics, you have a rather (passively) antagonistic relationship with a public intellectual I greatly admire - all things that in this day and age could be a turn off to engaging with someone BUT you really are the best, and perhaps most honest, public educator of difficult physics topics around right now.
Thank-you for this series and your contribution to public science education.
Dude, I am 62 years old... wish back in the day I had you (if I could go back in time and you stayed the same young age your are now) as a professor. You rock! Make things understandable to most. Love the Quantum info too!! Please do more. - Tom from Skokie, IL
Great work sean, thank you for taking time to make these podcasts. And for educating this generation and hopefully future generations to come, thanks from Ireland ☘
Thank you for doing your part explaining complex topics and making your mark on the internet. In the information age, this will live on forever and in the future you may even be regarded as a modern Aristotle-type thinker from the 21st century.
Cogito, ergo sum.
It’s some 20 years ago I learned Newtonian mechanics and conservative of momentum. Physics still fascinates me despite I have left the field for more than 10 years by now.
Thanks for the series.
I wish this existed when I started out in my physics training. Maybe I will show this to my children one day. My eldest is 7.
So many referentes you do on the podcast are explained here, spherical cow etc. Love the video.
Dr. Caroll, thank you so much for your podcast, books and your UA-cam channel. Love your work and thank you for being such an incredible communicator of science. All the very best to you and your family.
I reckon you could write a book from these talks.
You are so good at explaining these concepts that I think if it was in book form you could reach a wider audience.
I can listen to you for hours! great talks, sensible and understandable
I think your channel is going to become just great - keep pushing, keep it moving!
I liked your careful attitude to the history of science. I think it was very respectful and modest.
Woop woop! I'm reading the book along with the videos. Very well done!
Amazing. I wish I had you as a physics teacher in my middle and high school.
The idea of the spherical cow and its implications (as you have explained) should be explained in the first lecture in every middle and high school. In my experience students do not see the connection between the simplified physics they learn in class and the real physics they experience on a daily basis. This makes it hard for them to really appreciate the importance of the subject of physics to their life.
Thanks for talking about it.
Great video! Thanks for taking the time to make and share
Great video professor, I'm proud we are popularizing science through UA-cam and other medias nowadays, keep up the good work!
I rarely ever comment on anything on youtube, but I just wanted to let you know that i LOVE listening to you. I think NDT gets a ton of admiration and praise (rightfully so) for being the best at teaching/discussing REALLY intelligent ideas to the basic public in a way that is fun, desirable and educational. But you make me yearn for more, you make it SO exciting and so easy to develop a desire to want to understand more about physics. You and Brian Greene are my hero's! I think i may have chosen the wrong field for my career! :( #iwannabeaphysicists.
What is your field? I know, I'm 2 years late, but anyway... It's almost never too late to learn something new. Cheers.
(btw: sorry for nitpicking, but "heros" is plural and thus without an apostrophe)
This is more meditation than education. Thanks Sean 👏
With regards to Noether's theorem (1915), if we want to be more specific and inclusive, Emmy Noether was not the first person to discover the fundamental link between symmetries and conserved currents (energy, momentum, angular momentum, etc.). Many people in the physics community ignore this fact, but the intimate connection between symmetries and conservation laws was first noticed in classical mechanics by Jacobi in 1842. In his paper, Jacobi showed that for systems describable by a classical Lagrangian, invariance of the Lagrangian under translations implies that linear momentum is conserved, and invariance under rotations implies that angular momentum is conserved. Still later, Ignaz Robert Schütz (1897) derived the principle of conservation of energy from the invariance of the Lagrangian under time translations. Gustav Herglotz (1911) was the first to give a complete discussion of the constants of motion assiciated with the invariance of the Lagrangian under the group of inhomogeneous Lorentz transformations. Herglotz also showed that the Lorentz transformations correspond to hyperbolic motions in R3. What Noether did, was to put every case into the generalized and firm framework of a mathematical theorem
Thrilled to see Emilie du Chatelet getting some credit! 🙏🏽🤗
This is massively important for predictive modelling. Any simulation can go off the rails. The conservation laws provide a vital reality check.
like this new format thanks Sean
Thank you Sean. I’m happy and excited about these upcoming videos. Thank you very much sir.
This is great, while at home, physics lessons from the greatest! Thank you !
What an amazing approachable lecture
On a topic that unless someone maintained math physics and other acumen would potentially be in an accessible for the didactic approach teaching often takes
I think about these things all the time life does not allow me to return to first principles and what a wonderful alternative to still feel like you can understand concepts when a good teacher appears
Having done high school and university level physics only I can tell this series of videos is going to be extremely enjoyable inspiring and possibly very educational
Apart from my own enjoyment I am certain there will be people who will be motivated in either direction to the didactics and first principles or to be inspired and some other way
Thank you for this
I enjoyed this episode very much, looking forward to the next one!
love this new format!!
I love you Prof. Carroll
Hey, 100k....congrats and best wishes sir✌️
I love that I'm technically taking a class at CAL Tech with Sean Carroll
Kinetic energy is momentum in the TIME direction (the "ct" fourth dimension in Einstein's Relativity formulae). This was how he found the "E = m x c-squared)" relationship.
Thanks for this. I've always found Physics to be far more relateable (and interesting) by really going into Friction, Drag, etc. first. There are many everyday experiments you can do; dropping balls in honey, vs water vs air, sliding blocks on ice vs wood planes, etc. These reinforce a sense of exploration. Instead, we usu start with Galileo, and go right to frictionless planes and perfect collisions, without directly replicating that journey. Students hear it as i.e. "accept the enlightenment of the experts and you will understand" which is very anti-science. Only in college do we finally fill in those missing blocks and it all becomes real.
Thanks, Sean. Watching from quarantine in France.
Thank you Sean. I will be pointing my Alevel students in this direction.
Thank you, Sean! Please keep them coming!
genius of physics
How is it that an electron and a proton have the exact same magnitude of charge?
This is so exciting :)
Its so funny to see you talking about these concepts because I went through your great courses thing and its funny to see the person not just the voice, you're a great teacher.
Such a great break down of this..you've bin teaching me for years now...I actually know things!!! Lol. Thank you..keep em coming:)
Thanks very much for this series. Got to keep the neurons firing in the face of the monotony of the pandemic.
Fantastic. Love these informal series!!!
(this series is about mathenaticians setting the value of the universe to 1(one) - where they obviously should have set the value of the universe to infinite/infinite acelleration)
Did you seriously just draw an arrow below an arrow to indicate the direction of travel of the arrow? I am so happy about this. :)
Economics definitely uses spherical cows. Here's a joke economics tell each other:
A physicist, an engineer and an economist are stranded in the desert. They are hungry. Suddenly, they find a can of corn. They want to open it, but how?
The physicist says: “Let’s start a fire and place the can inside the flames. It will explode and then we will all be able to eat”.
“Are you crazy?” says the engineer. “All the corn will burn and scatter, and we’ll have nothing. We should use a metal wire, attach it to a base, push it and crack the can open.”
“Both of you are wrong!” states the economist. “Where the hell do we find a metal wire in the desert?! The solution is simple: ASSUME we have a can opener”…
But you're right in that one of the big tensions in economics is when theory and empiricism clash (e.g., minimum wage) and that's probably not as big of a deal in Physics, where it's much easier to test.
Mark Carroll You are right that econ uses its versions of the spherical cow, much more so than any other social science. Maybe this is how economics managed to become much more quantitative and precise than other social sciences. It has given rise to the criticism of “physics envy” , mainly by non-economists who may in turn envy economists. On a quibble, the debate over minimum wages is actually a good example of the success of the spherical cow. With a perfectly competitive labour market, raising it cuts employment. In a justly famous article Card et al. discovered a case in which this didn’t happen. They didn’t conclude that economics is all wrong, but that there must be something else at work, such as that the smallish local labour market they studied might not be perfectly competitive, in which case raising the minimum wage could raise employment.
A LOT of spherical cows in economics. You beat me to it. Here's a list of some classics
- Perfect competition
- Representative agent
- Rational agent
- Time consistent preferences
- No arbitrage
- Benevolent government
- Full information, or at least full information about the probability space
- Non-decreasing average costs
Hi Mark, good joke by the way.
So i'd say the biggest answers in physics as well as in economics came from exactly the points on which theory and empiricism clash.
And they both tell us a story about nature.
Mark Carroll A Carroll correcting another Carroll...
Good one SC;great approach
I know...there is no stupid question...but there is one I have...IDK (sorry for my bad english) Everything is moving...The Earth is moving...Me is moving....An Atom is moving...Electrons are moving...Protons also....I know, there is quantum movement...even the so called "Nothing" is moving....But is there a state of something , where the Matter is in a rest state? I mean, even we on earth, every Atom is moving...Earth is moving around the Sun...Sun is moving around the Milkyway...Milkyway is moving around the...You know what I mean...Is motion a constant state of matter or is there even a term of a particle that is not in motion?? Is there a Particle somewhere in Universe, somewhere between Galaxies, that does not "feel" gravity or any force and does not move at all...I hope you understand what I mean....I would be very greatful for an answer!!! ♥ :)
Galileo (1564-1642); Newton (1642-1726) - important dates to keep in mind for the historical time frame of reference.
Love this!
Is it accurate to say that the laws of physics are simply descriptions of very regular patterns in the universe? Is the scientific community essentially looking for and attempting to accurately describe regular patterns? Or have I misunderstood?
" say that the laws of physics are simply descriptions of very regular patterns " - yes, that is the working premise. This is different than the old fashion approach of needing a deity to declare/create rules, or the self-defeating idea that the universe is too random or too hard to be understood (at least in some useful sense.)
Love the video's! When are you doing a new course on TTC? I did follow the " older" counrces but it would be so cool to have the new insights that are there now!
Just starting the vid, but thanks for continuing to hook us up with the good word :D
My favorite new physics channel. bravo, sean. Also love the split-screen interface.
Obsessed with the intellects! Thank you for the lessons, making it accessible to those of us that have no background, the patience involved with this and hitting so many areas the vast majority of us are curious on but had no way of knowing where to start. I crave the day that all ladies understand intellectual power over brute force. These are our lovers, the others are cavemen yuck 🙈🙉
wonderful, absolutely brilliant :)
Loved it. Please do more!
Physics has changed to the same degree that the tools we use to make tools need to be better than the tools we make with them..Also one depends on the written history of others when we make propositions...?
This is just what I was needing while looking at a couple of weeks of self isolation. One thing I wonder about is spin: planets, stars, particles, all spin - could we find a way to determine if the cosmic microwave background radiation is also 'spinning'?
My man!!
Conservation of momentum does not seem to come into play into the development of statistical mechanics (as defined by Gibbs, 1902). The closest thing I can see is the use of the Hamiltonian Mechanics in the derivation of the canonical ensemble probability formula. What does the conservation of momentum add to the thermodynamic picture?
Is this filmed on a webcam? I know that's not supposed to be the focus of this, but I think you might want to use your smartphone instead. Makes the editing a little trickier if you don't have a good microphone you can connect to it but the video quality will be incomparable and you won't have to invest in a real camera or a lot of cinematography skills because modern smartphone cameras are pretty wild.
I just wondered; when a positron meets an eletcron, they annihilate each other and are turned into energy. But what happens when an anti-nutrino meets a proton?
The great mind !!! Opened my eyes years ago!
Great vid and topic
I have a question:
What's the relationship between conservation of energy and conservation of momentum? That is to say, how are they related to each other?
For example, I notice that one way to get kinetic energy from momentum is to integrate with respect to velocity, but what does that even mean? How is that interpreted?
The best I can do is that changes in energy (with respect to velocity) are caused ny momentum, but I don't think that's quite it and it isn't satisfying at all.
literally half of this vid answers that question, try watching it, he even writes out the formula for you
Sean Carroll very much overstates the role of Émilie du Châtelet. Perfectedly understandable of course in this time and age, but historically incorrect. The actual experiments were done by Polleni (see en.wikipedia.org/wiki/Giovanni_Poleni ) and 's-Gravesande (see en.wikipedia.org/wiki/Willem_%27s_Gravesande ). Du Châtelet incorporated their discoveries in the story, no more, no less.
Thanks for these videos, Sean. I really enjoy them. But honestly, a cylindrical cow is a closer approximation to an actual cow.
Looking forward to more videos!
Love it! Thanks Sean!
Actually there is a spherical cow concept in economics: it’s the concept of the evenly rotating economy as described by Ludwig von Mises in his book, Human Action.
you should add the video to your podcasts
While you are imagining a spherical cow, I'm imagining a universal cow.
I have a question regarding how orbiting bodies lose momentum to gravitational waves. Does this imply that even in the vacuum of space, given enough time, an object will slow down and stop (similar to air resistance on earth)?
Hi Sean, thanks for starting for this series and going to the heart of key concepts which generally not taught in the class. For example, why the idea of conservation of momentum is a paradigm shifting idea. I have a question about the Higgs field. Sometimes I have heard that Higgs field is like a molasses or viscous fluid which drags on the particles to give them mass. I can understand this to some extent when one tries to move a particle at rest, the viscosity will resist it hence the inertia. But molasses or viscous fluid will not let a particle to move at constant speed. It will slow it down. That is why I do not like molasses analogy. Instead I like the photon-box analogy for mass. What are your thoughts on this. I try to insist on use of correct analogies with non-physics educated people because it gives wrong impressions if the wrong analogy is used. Thoughts?
This was a great start, thank you very much Sean.
Can’t wait for the rest.
Aristotle: One of the great, most profound thinkers of all time.
Also Aristotle: Some is pure "bro science" in today's terms. Aristotle's arrow explanation is a great example of Bro science in the Classical Age.
If someones interested in the History of Physics (and can understand German) there is a youtube show called "Von Aristoteles zur Stringtheorie". It´s pretty good.
How old is the spherical cow idea? The Russian version talks about a spherical horse in vacuum (and the story itself is a bit lengthier). I wonder if it was adapted or developed independently.
Did you accidentally mix up inelastic & elastic collisions? You described billiard ball collisions as elastic & silly putty collisions as inelastic.
I'd have thought they'd be the other way around... Unless I'm misunderstanding something?
@@michaelsommers2356 Ok, thank you.
Great video! Keep them coming! :)
Man this is awesome. Thanks.
11:00 - did Aristotle already know air and its resistance? If true, a big surprise!
Thank you for this!
Very interesting!
Thank you!
The place we fundamentally disagree is that experience has taught me that Consciousness is more likely a Universal Field than something generated by the brain. The brain is the focal point, not the generator.
As shocking as it may sound, the Universe really is alive. I had to abandon Materialism after my third prophetic dream, it simply no longer explained my experiences. But you are exactly who you should be, as am I. Finally.
thank you for the lecture
There is visible light we see. Colors during the day but At nighttime or in a dark room no colors. If you look into the night sky what you see appears black, or is it colorless. Question. What color is space?.
I wish you taught at my high school......my science/physics teacher was also the P.E. teacher, so if it wasn't related to football........
Cool!
synchronicity.
i had never heard of this spherical cow thing until today, on youtube, about two hours ago, weird.
AdS/CFT correspondence?
0:55 true that. at highschool and college i definetly had problems with balls bumping into each other.
Well deserved flex of the spherical cow award :D
Since we live in a world in which all things are in motion, how do we scientifically test whether there is or is not a force that moves and transforms everything in the universe?