Thank you! I was wondering for a while why the planck length is the smallest length we can work with in physics. I read about it, watched some videos, but your video made me finally understand it. Great combination of explaining with words, mathematics and visualisation!
same here. now it finally makes sense. to "measure" anything you have to bounce some energy off it and detect the changes in the reflection of that energy vs how that energy would react if the object was not there. at planck length things are so "flimsy" that any energy added is enough to overwhelm it into collapsing. of course the black hole allows no information to be outputted, thus no measurement. thanks so much for this video!
And yet it shows how flawed and confused “modern” physics is, and how it fails to comprehend and cohere with the Logos (Universal Logic - the True Origin and Ruler of the Cosmos who is the only Real God) . They constantly try to use Reason (the “math” they often call it, as if the forms of Logic don’t share and cohere with an Essence they all originate from, as even ancient philosophers in Israel, Egypt, and Greece (among other places like India) knew. If you want to understand the Universe and have a coherent understanding (unified theory) then you MUST understand THE Law (the Unmoved Mover - the Logic - God) who all coherence is held together with, as, and by. Coherence without Oneness and existing (contingent) logical concepts without the Whole of Logic (Logical Completeness - Echad) would be a contradiction. When the arrogant physicists stop denying that ALL their evidence (that is logically coherent and actually legitimate and not a bunch of crap like a lot of “science”) is evidence of the Source of Evidence (Logos - YHVH - Dynamic Natural Order/Logic - Ma’at) and when they stop being fools that arbitrarily declare “we don’t know” as if they know what I know and all that is known (yet they can’t explain the perfectly intelligible Coherent Origin/Truth/Reality/God?), and when they ASK and LISTEN, then they TOO will know Logos and all the knowledge that Logos holds (all knowledge).
Their physics can only break down because it’s NOT the Universal Logic (Unified Theory - First Cause - First Law of True Logic - YHVH) that they are reckoning with. They are reasoning with a flawed logic (false god) and thus it fails them as wiser minds like Moshe and Aristotle told us flawed reasoning does in their legendary writings. To understand Reality you must learn the Logic of Reality by observing Reality (God) and you MUST go through the Gatekeeper (the Logic of Reality - Logos). Those who object to the circularity of that Tautological Truth (Logic of Reality) object to Tautology, Logic, and the need for human understanding (our personal logic/god) to come from respect for Natural Order (the Logic/God of/in Reality/Truth). Those who can’t understand that are not ready to move beyond it yet into the minutia of discrete reality. First, like you climb a mountain from the base to the top, and like you put the horse in front of the cart, people must grasp the First Cause/First Law/Universal (Logic/Unmoved Mover/the Creator & Foundation of the Universe - the Physically and Metaphysically Consistent Logic.
Years ago, I saw a program on PBS in which a physicist was explaining Planck measurements and he casually mentioned something about the formation of a black hole. I never really could grasp what that was all about. Now I have. Thank you.
I was brought to believe beyond the Planck scale is absolute entropy. PBS is a great Chanel for sure and a great starting point for those who want to know, gotta take it from there and do something with it. My understanding is we exist between 2 realms , that & absolute zero which both are yet to be determined but are theorised closely. Planck should be all around us go through us as we travel through it like a Great Wall separating absolute chaos from this dimension or it’s easy to imagine what happens. Lots left to explain like the lattices of Planck perimeter and it’s perimeters width which is smaller then planck itself. Newton had perimeters at about .002 mm and presently it may not be the case anymore but like PBS it’s a start. At this speed answers will be flying in because we never give up.
One of th most underrated vid on yt. Explaining 2 complex concepts in less than 20 min and without jargon or mathematical barriers... Sometimes internet is worth it after all.
Love the explanation, but there’s a slight issue. E=pc only applies to objects with a very low rest mass compared to their momentum, while E=mc^2 only applies to objects with a very low momentum compared to their rest mass. You can’t use both equations in the same derivation, since that implies m
I'm sure the presenter is smart, but anyone sufficiently curious could read the books and learn the constants and basic mathematics shown here and figure this equation out for themselves - it's the fact that the Planck length can be defined in such simple mathematics, when described on top of the mountain of work that produced the theories of Quantum mechanics and general relativity, that I am in awe of. Also, as they point out, it's not that the Planck length "exists", it's that it describes a limit of the theories and models themselves - within certain constraints the theories work, outside of those constraints we just don't know.
It’s not necessarily about being smart, it’s about having a genuine interest in a subject and studying it for years. Anyone can be this smart if they just put the time into it.
Great video. I wish people would not say "physics break down" about this sorta stuff, though. It misled me for a long time in relation to black holes/singularities. It's not technically wrong. Physics- the science, what we know about how the universe works, yes that "breaks down" in these extreme situations. But many people think, like I did, that this is saying the universe breaks and stops working and returns a blue screen of death. There's very little reason to believe that's the case. It's more likely that something predictable happens and it's governed by laws of physics, just ones we don't and possibly cant know. To me, this difference was a rather profound one, and avoiding the language "physics breaks down" or at least explaining your use of the phrase would probably help others like me with this misconception.
There is an intuitively simpler concept without the delta P and x maths stuff. 1) At very small scales below protons, there is no solid matter..it is all packets of energy 2) As the frequency of a photon (energy packet) rises, so does its energy, but the wavelength gets correspondingly shorter 3) You must reach a point where the high energy - mass equivalence fitted into the small wavelength reaches the Schwarzschild radius….Bingo! Blackhole and the photon drops out of existence. This gives a minimum wave length of Planck size…An over simplification of course and doesn’t account for Quantum effects..or Hawking Radiation…But it provides an imaginable mechanism. This is how I understood and calculated the minimum length back in my college days thirty years ago! I went in to realised crossing the smallest length (Planck) at the highest possible speed … C … provided a minimum length of possible time (10e-43s) or the Planck time interval. I was quite proud of these workings using pretty basic physics formulae since my maths algebra ability is poor and stuff like calculus is beyond me. This means the space around us is seething foam of holes. Like the safety net below a trapeze artist…anything bigger than the holes rolls around through space, but anything smaller pops through the holes and is gone. What happens to that missing energy is unclear…maybe it Hawking radiates immediately out as a new radiation? Or a quantum effect ‘deals’ with it…Beyond my knowledge cache.
Everything you say is correct, but Planck published his work on the Planck length in 1899. He didn't have Einstein, Heisenberg, quantum theory, black holes or anything you mentioned to do his work. Planck used only fundamental constants to derive this. Based solely on the units of the constants he had, he was able to derive distance (length). The later work shows why this works out, but it is truly impressive to think of the idea that there must be a smallest length and then derive it out of nothing but known constants.
Matt, I don't really comprehend all the math, but how you explain it leaves me speechless. You have a gift for teaching. I kinda got it, & I subbed too!
Thank you, wonderful video. If I understand correctly, the Planck Length doesn't say it is the smallest possible space for sure but from this point most of our physics laws, formulas and theory don't work anymore
He kind of glossed it over in this video, but you would need the maximum frequency high gamma to see that small, and that would require so much energy that it would -turn itself- into a black hole. So there can be smaller low energy particals under the plank leght, but as mentioned in the video, only a better theory of quantum gravity could let us glimps its secrets. For now. @@LupusUmbra995
I find the wording a bit strange. I don't know if this is considered synonymous but I wouldn't see it as the smallest length. It's the highest accuracy you can achieve when trying to place a particle in an exact position. The energy required to bring the uncertainty any lower will break everything.
But I think his “L” refers to the actual size of the object, not its position (x) or accuracy in measuring its position. There must be an assumption that possibilities for its position x are proportional to its size L, and that one must be smaller than the other, since he subs L for x. So the concept here is about size (L), not about Heisenberg limits or accuracy of measuring its position (x).
I couldn't follow the math at all, but the explanation of Planck Length being related to the Schwarzchild Radius was very enlightening. We can't see things smaller than that because they would be a singularity. Wild.
That was a very cool video and you did the maths in such a way where it doesn’t fell at all (or rather, entirely) intimidating. Thank you for taking the time to make this and make it understandable for those looking to greater their understanding of the quantum.
Thank God for RUclipsrs who aren't afraid of formulas. I seriously HATE those idiots who apologize in advance for showing, as short as possible, a (simple) formula, immediately assuring the viewer "don't worry, this will be the last formula" and stating that they know that formulas are intimidating and scary and they won't do it again. Result: you learn NOTHING.
I haven’t seen those apologies for formulas, but… isn’t that somewhat condescending? To imply that the audience can’t handle formulas? Or does the sentiment come from groans in the comment section?
@@epicepidemic7131 MOST youtubes that I encounter, while looking for vids to learn something from are like that - and the comment is made by the youtuber, not something in the comments of the vid no. If you know other vids that go into the details, with as much formula's as needed, that aren't just live college lectures, then let me know!
Fun fact to blow your mind: Compare the average human body size to the planck length and to the size of the known universe: The human body comprises more planck lengths than the universe comprises human body lengths. The difference is enormous.
4:10 it would have been clearer if you used the full relativistic energy formula and explain that the m^2 c^4 part can be ignored since we are looking for the lowest allowed energy. Also this channel has a lot of potential. Good luck!
Thanks for watching, and for your comment! Indeed that’s where the expression comes from. I hadn’t really considered introducing it that way, I thought it would be easier not to go into it, but the explanation may well have been more complete with that addition. Thanks for your support, I hope you enjoy my future videos :)
@@shotsinthequark As you wrote down "E = pc" I was thinking " ok,we are only talkiing about massless particles now". Then you wrote down "E = mc^2" and I was thinking "wait, I thought we are only considering massless particles"...
The thing you forgot to mention is, the Lp only matters, if an object (particle) is considered. For "empty space" this does not apply, at least when if we don't think about vacuum fluctuations at this point.
The other explanation of this I heard was that to understand what's happening below planck length, we need to probe with a quantum particle whose wavelength is smaller. Such a particle has such high energy that its mass equivalent is so dense it forms a black hole with a event horizon that is slightly bigger than Planck length. If we tune things a bit, the point where event horizon size and wavelength of the quantum particle actually meet is exactly the planck length. An analogy: If you think about your phone screen, the pixel count - and therefore pixel size - is the maximum screen resolution. Smaller pixels same screen size means higher resolution. The planck length represents the maximum resolution of our universe.
@@yon5925 We can't observe beyond an event horizon because the escape velocity exceeds the speed of light. Arguably from an outside observer's view time stops at the event horizon as well - so you're right in stating the effect.
Thanks for this. Here's how to try to picture the size of a Planck Length. Take a Hydrogen atom (529 × 10^-10 metres!) and magnify it until it is the size of our galaxy (100,000 LY across) then if we zoom right down to our own scale, a Planch length is about the size of a paramecium, and is almost visible! If that doesn't make your head hurt, then think about this: We use the speed of light to define time. And we use time to define the speed of light.
I see where several commenters wanted to know the value of the Planck length. If I recall correctly, the universal gravitational constant, G = 6.67 E-11 N m^2 kg^-2, Planck's constant, h = 6.626E-34 Js, h-bar = h/(2*pi), the speed of light, c = 3E8 m s^-1. Thus, the Planck length is 1.61E-35 m.
This number is so small, but sooooo small, that it's in the range of the 10e-5 part of the lowest SI prefix of quectounit, which in turn corresponds to anything multiplied by 10e-35.
That was awesome ! Thank you so much. As a musician and social worker, I’m fascinated with quantum physics, but have no formal education on the subject. Your explanation of the Planck length may be the first I’ve understood enough to make ‘some sense’ out of the paradoxical world of quantum physics.
Thanks for this. I'm not a scientist or mathematician, and I pick up only what I think is the gist of the argument. Nonetheless I very much enjoy listening and learning, and thinking about how some of these ideas come together in the most fascinating ways.
OMG! This video is the BEST explanation I've ever seen on why the Planck length "may" be the smallest meaningful distance in our universe. The math you used wasn't super-difficult to follow. In this one video, in just a few minutes, you not only explained "why" Planck length is the lower limit on size, you also explained why the Uncertainty Principle doesn't allow us to know both the position and momentum of a particle to the same level of precision, and why quantum physics and General Relativity have not yet been unified in a way that can explain both the very smallest and very largest phenomena in the universe. I just had basic physics and chemistry classes in high school in the 1970's, and my own readings of science-related material since then, so I am 100% a layman, yet everything you said made perfect sense and it was easy to follow your logic and make the connections in my mind that you are trying to teach here. Your students are the luckiest on earth to have you as their instructor.
I never understood this before, but it was explained so clearly that around halfway through the video I was already predicting the end of it. Thank you!
This is a perfect video! Short and sweet, and genuinely enlightening. As soon as you explained the relationship between mass and measurement it clicked. Thank you
In signal processing we talk about the Nyquist rate. This is the minimum rate where we can perfectly reconstruct a band limited signal. I’ve always wondered if this could be applied to spatial sampling and solve Xenos paradox.
I'm glad you ended with acknowledging that we need a unifying theory to know if the Planck length is actually the smallest area OR if it is just our understanding of physics and the math that is breaking down.
Planck length makes me feel like we're living in a simulation and the Planck length is the resolution of the system it's running on the same way video games have a finite resolution or accuracy in their engine.
I feel like I owe you tuition. That was a very easy to understand and intuitive way of explaining this concept. This made me look forward to advanced physics classes I will be taking over the next few years. Thank you!
Plank length is the smallest theoretical length you could measure, however you can always divide it down to smaller lengths, they just would not be measurable. In short if you tried to "look" at a plank length you form a plank length black hole that would be at the plank temperature for a plank time and then evaporate.
Excellent presentation. Although physics is not my chosen field, I am a scientist, and I've studied physics as a hobby for decades. My observation is that the two areas that will push physics to the next level are: 1. A better theory of quantum gravity that can be verified, and 2. A much deeper understanding of what is actually going on with quantum entanglement. The absurd weakness of gravity, and the apparent violation of special relativity by quantum entanglement, are the biggest clues that something important lies just underneath the space-time-matter-energy canvas that all of modern physics is painted on. But whatever theory is suggested to better explain these two phenomena - it has to be testable - that is, if we really want to get to that next level. In my opinion, it is time for a renaissance in physics where we take a hard look at known problems that are today, for whatever reason, largely ignored by the physics community.
just waw, I'm no physicist, but I hear of planck length regularely for 20 years now, and it's the first time I see the math behind it. Astonishing. A real big tahnk you
I’m thinking you might be the guy who could explain to us how Schrodinger and Heisenberg were able to determine that space was pixelated (not SMOOTH!) at the Planck scale, and why, after making this determination, it caused Schrodinger to comment that, if he had known it would come to this, he would have preferred NOT to have been involved… I need all the help I can get here!
Question: if Lp, the Planck length, is the smallest something can be, is it also the smallest difference between two lengths? I.e. I can have two particles be 100 Lp apart, but can I have them 100.1 Lp apart?
This is such a wonderfully well explained video. I actually had this question for a long time and thank god for the RUclips algorithm to suggest this video to me because it answers just that. Thank you.
Thank you! I never understood why you couldn't have a length smaller (or rather, know anything about a length smaller) than the Plank Length. Now I do (as much as I can!)
Well explained for such a complex subject, like I understood any of it lol But you almost made me feel like I understood something there, I more or less got an idea of what you were explaining. I would only suggest a slightly higher audio next time, it was ok but somewhat a little bit low, but really, great video. Keep it up !
I like this explanation, and I think it should give those of us not fully immersed in modern physics some confidence that the Planck length is a real limitation. Maybe it is just a limiyof our models, but the photoelectric effect seems a solid indication of quantum energy, and quantum mass and quantum length come right from that. This really made it easy to understand the connection.
I've seen many explanations of the Planck length, and yours is the 1st I've grokked. Your use of word atom is very appropriate, as in Greek it means indivisible.
Shout out to Max Planck who discovered this constant by accident, using a mathematical hack to solve the "ultraviolet catastrophe". He basically said "let's pretend that energy comes in quanta" and suddenly all the problems with our understanding of blackbody radiation disappeared. He expected his Planck value to be precisely zero, and that the problem was measurement, but it wasn't zero, it was very slightly above zero, so what he actually did was to discover quantum mechanics. The "let's pretend" method of discovery is wonderful. Euler did a similar thing when discovering complex numbers. He basically said "let's pretend there's a solution to the square root of -1, and we'll call that number i" and in doing so, previously unsolvable equations were now solvable.
I just found your channel. I look forward to what you do in the future as I’ll be back at university in the spring finishing my physics degree. Good luck!
That was a really good physical and mathematical derivation of the existance of the Planck length for me whon doesn't have a background in quantum physics.
Thanks for putting that all together for me. I was familiar with the concept but not the "why". Now I know. The math is actually fairly simple which is the biggest surprise of all.
This might be an almost obscene question under such a video, but could someone explain to me, why at 6:00 the substitution of E with mc^2 makes m>h^2/(l^2*c^2) instead of just m>h^2/l^2 ? Total physics/maths noob here, I'm wondering on an algebraic level...
Thank you! I was wondering for a while why the planck length is the smallest length we can work with in physics. I read about it, watched some videos, but your video made me finally understand it. Great combination of explaining with words, mathematics and visualisation!
Thanks very much! It's fascinating to know what exactly the Planck Length is, thanks for watching and for your comment :)
Can't agree more! I am so glad to have found this video.
same here. now it finally makes sense. to "measure" anything you have to bounce some energy off it and detect the changes in the reflection of that energy vs how that energy would react if the object was not there. at planck length things are so "flimsy" that any energy added is enough to overwhelm it into collapsing. of course the black hole allows no information to be outputted, thus no measurement. thanks so much for this video!
Well, good for you. The more math involved, the less I comprehend.
@@shotsinthequark Same here. Talk about lightbulb going off. I now understand why.
This is the best explanation of Planck length I've ever heard. Excellent synthesis of the math and the concepts. Thank you!
And yet it shows how flawed and confused “modern” physics is, and how it fails to comprehend and cohere with the Logos (Universal Logic - the True Origin and Ruler of the Cosmos who is the only Real God) .
They constantly try to use Reason (the “math” they often call it, as if the forms of Logic don’t share and cohere with an Essence they all originate from, as even ancient philosophers in Israel, Egypt, and Greece (among other places like India) knew.
If you want to understand the Universe and have a coherent understanding (unified theory) then you MUST understand THE Law (the Unmoved Mover - the Logic - God) who all coherence is held together with, as, and by.
Coherence without Oneness and existing (contingent) logical concepts without the Whole of Logic (Logical Completeness - Echad) would be a contradiction.
When the arrogant physicists stop denying that ALL their evidence (that is logically coherent and actually legitimate and not a bunch of crap like a lot of “science”) is evidence of the Source of Evidence (Logos - YHVH - Dynamic Natural Order/Logic - Ma’at) and when they stop being fools that arbitrarily declare “we don’t know” as if they know what I know and all that is known (yet they can’t explain the perfectly intelligible Coherent Origin/Truth/Reality/God?), and when they ASK and LISTEN, then they TOO will know Logos and all the knowledge that Logos holds (all knowledge).
Their physics can only break down because it’s NOT the Universal Logic (Unified Theory - First Cause - First Law of True Logic - YHVH) that they are reckoning with. They are reasoning with a flawed logic (false god) and thus it fails them as wiser minds like Moshe and Aristotle told us flawed reasoning does in their legendary writings.
To understand Reality you must learn the Logic of Reality by observing Reality (God) and you MUST go through the Gatekeeper (the Logic of Reality - Logos). Those who object to the circularity of that Tautological Truth (Logic of Reality) object to Tautology, Logic, and the need for human understanding (our personal logic/god) to come from respect for Natural Order (the Logic/God of/in Reality/Truth).
Those who can’t understand that are not ready to move beyond it yet into the minutia of discrete reality. First, like you climb a mountain from the base to the top, and like you put the horse in front of the cart, people must grasp the First Cause/First Law/Universal (Logic/Unmoved Mover/the Creator & Foundation of the Universe - the Physically and Metaphysically Consistent Logic.
Years ago, I saw a program on PBS in which a physicist was explaining Planck measurements and he casually mentioned something about the formation of a black hole. I never really could grasp what that was all about. Now I have. Thank you.
Thanks a lot for your comment! Glad I've been able to make such interesting matters a bit clearer for you!
The video you mentioned ruclips.net/video/snp-GvNgUt4/видео.html
I wonder the radius of the earth needed to transform the earth into a black hole, it's probably not much beyond several meters.
I was brought to believe beyond the Planck scale is absolute entropy. PBS is a great Chanel for sure and a great starting point for those who want to know, gotta take it from there and do something with it. My understanding is we exist between 2 realms , that & absolute zero which both are yet to be determined but are theorised closely. Planck should be all around us go through us as we travel through it like a Great Wall separating absolute chaos from this dimension or it’s easy to imagine what happens. Lots left to explain like the lattices of Planck perimeter and it’s perimeters width which is smaller then planck itself. Newton had perimeters at about .002 mm and presently it may not be the case anymore but like PBS it’s a start. At this speed answers will be flying in because we never give up.
the radius you're asking about is called the schwarzschild radius, and for earth it is 0.88 cm, or 0.0088 meters@@_lcfiorini
Wow. Two of the most complicated concepts in physics, combined, and explained in very real world terms, in under 10 minutes. VERY well done!
One of th most underrated vid on yt.
Explaining 2 complex concepts in less than 20 min and without jargon or mathematical barriers...
Sometimes internet is worth it after all.
Love the explanation, but there’s a slight issue. E=pc only applies to objects with a very low rest mass compared to their momentum, while E=mc^2 only applies to objects with a very low momentum compared to their rest mass. You can’t use both equations in the same derivation, since that implies m
I agree completely (except that it is a slight issue, your point is correct and makes this a meaningless derivation)
Agree
Thanks for this clarification! But did you really kill a narwhal?
Real ones wanna know @@epicepidemic7131
Man this was amazing. I think this guy taught us something that a professor at MIT cannot do in a whole year. Excellent video. Keep it up
Oh man this channel is gonna be huge someday. You have a gift
I'm convinced this dude is an advanced life form from another planet. I can't even fathom what it would be like to be this smart.
It's gotta be frustrating for sure. I graduated cum laude at age 35 and I can't stand my fellow Americans.
@@adamwalcott_official As a mathematics honours student, I can confirm that Americans are extremely annoying.
I'm sure the presenter is smart, but anyone sufficiently curious could read the books and learn the constants and basic mathematics shown here and figure this equation out for themselves - it's the fact that the Planck length can be defined in such simple mathematics, when described on top of the mountain of work that produced the theories of Quantum mechanics and general relativity, that I am in awe of.
Also, as they point out, it's not that the Planck length "exists", it's that it describes a limit of the theories and models themselves - within certain constraints the theories work, outside of those constraints we just don't know.
It’s not necessarily about being smart, it’s about having a genuine interest in a subject and studying it for years. Anyone can be this smart if they just put the time into it.
@@RESIST_DIGITAL_ID_UKYou need to talk to more people. Not everyone can be this smart. Intelligence =/= knowledge.
Great video. I wish people would not say "physics break down" about this sorta stuff, though. It misled me for a long time in relation to black holes/singularities.
It's not technically wrong. Physics- the science, what we know about how the universe works, yes that "breaks down" in these extreme situations.
But many people think, like I did, that this is saying the universe breaks and stops working and returns a blue screen of death. There's very little reason to believe that's the case. It's more likely that something predictable happens and it's governed by laws of physics, just ones we don't and possibly cant know.
To me, this difference was a rather profound one, and avoiding the language "physics breaks down" or at least explaining your use of the phrase would probably help others like me with this misconception.
This is by far the best explanation for what the planck lenght is that I have seen. Fantastic! Thank you
Subscribed 😊
Ya incredible job
There is an intuitively simpler concept without the delta P and x maths stuff. 1) At very small scales below protons, there is no solid matter..it is all packets of energy 2) As the frequency of a photon (energy packet) rises, so does its energy, but the wavelength gets correspondingly shorter 3) You must reach a point where the high energy - mass equivalence fitted into the small wavelength reaches the Schwarzschild radius….Bingo! Blackhole and the photon drops out of existence. This gives a minimum wave length of Planck size…An over simplification of course and doesn’t account for Quantum effects..or Hawking Radiation…But it provides an imaginable mechanism. This is how I understood and calculated the minimum length back in my college days thirty years ago! I went in to realised crossing the smallest length (Planck) at the highest possible speed … C … provided a minimum length of possible time (10e-43s) or the Planck time interval. I was quite proud of these workings using pretty basic physics formulae since my maths algebra ability is poor and stuff like calculus is beyond me. This means the space around us is seething foam of holes. Like the safety net below a trapeze artist…anything bigger than the holes rolls around through space, but anything smaller pops through the holes and is gone. What happens to that missing energy is unclear…maybe it Hawking radiates immediately out as a new radiation? Or a quantum effect ‘deals’ with it…Beyond my knowledge cache.
Everything you say is correct, but Planck published his work on the Planck length in 1899. He didn't have Einstein, Heisenberg, quantum theory, black holes or anything you mentioned to do his work.
Planck used only fundamental constants to derive this. Based solely on the units of the constants he had, he was able to derive distance (length). The later work shows why this works out, but it is truly impressive to think of the idea that there must be a smallest length and then derive it out of nothing but known constants.
Matt, I don't really comprehend all the math, but how you explain it leaves me speechless.
You have a gift for teaching.
I kinda got it, & I subbed too!
Thank you, wonderful video. If I understand correctly, the Planck Length doesn't say it is the smallest possible space for sure but from this point most of our physics laws, formulas and theory don't work anymore
and at any smaller than that "length" any particle would be reduced to a black hole, which we then would not be able to observe it.
He kind of glossed it over in this video, but you would need the maximum frequency high gamma to see that small, and that would require so much energy that it would -turn itself- into a black hole. So there can be smaller low energy particals under the plank leght, but as mentioned in the video, only a better theory of quantum gravity could let us glimps its secrets. For now. @@LupusUmbra995
I find the wording a bit strange. I don't know if this is considered synonymous but I wouldn't see it as the smallest length. It's the highest accuracy you can achieve when trying to place a particle in an exact position. The energy required to bring the uncertainty any lower will break everything.
Yes, I’d say this is the main message of the story. Thanks!
But I think his “L” refers to the actual size of the object, not its position (x) or accuracy in measuring its position.
There must be an assumption that possibilities for its position x are proportional to its size L, and that one must be smaller than the other, since he subs L for x.
So the concept here is about size (L), not about Heisenberg limits or accuracy of measuring its position (x).
Great video man and well put
I couldn't follow the math at all, but the explanation of Planck Length being related to the Schwarzchild Radius was very enlightening. We can't see things smaller than that because they would be a singularity. Wild.
ikr Schwarzchild radius explained a lot
He said event horizon.
Nothing about singularity.
Very deliberately.
That was a very cool video and you did the maths in such a way where it doesn’t fell at all (or rather, entirely) intimidating. Thank you for taking the time to make this and make it understandable for those looking to greater their understanding of the quantum.
Thank God for RUclipsrs who aren't afraid of formulas. I seriously HATE those idiots who apologize in advance for showing, as short as possible, a (simple) formula, immediately assuring the viewer "don't worry, this will be the last formula" and stating that they know that formulas are intimidating and scary and they won't do it again. Result: you learn NOTHING.
I haven’t seen those apologies for formulas, but… isn’t that somewhat condescending? To imply that the audience can’t handle formulas? Or does the sentiment come from groans in the comment section?
@@epicepidemic7131 MOST youtubes that I encounter, while looking for vids to learn something from are like that - and the comment is made by the youtuber, not something in the comments of the vid no.
If you know other vids that go into the details, with as much formula's as needed, that aren't just live college lectures, then let me know!
Fun fact to blow your mind:
Compare the average human body size to the planck length and to the size of the known universe:
The human body comprises more planck lengths than the universe comprises human body lengths. The difference is enormous.
This was awesome, I have always wondered about the smallest object and length and without the math it still makes sense to me, Well done.
Thank you for your video, I’m no longer insecure over my little planck!
FINALLY a video that actually explains the planck length properly and concisely
4:10 it would have been clearer if you used the full relativistic energy formula and explain that the m^2 c^4 part can be ignored since we are looking for the lowest allowed energy.
Also this channel has a lot of potential. Good luck!
Thanks for watching, and for your comment! Indeed that’s where the expression comes from. I hadn’t really considered introducing it that way, I thought it would be easier not to go into it, but the explanation may well have been more complete with that addition.
Thanks for your support, I hope you enjoy my future videos :)
@@shotsinthequark As you wrote down "E = pc" I was thinking " ok,we are only talkiing about massless particles now". Then you wrote down "E = mc^2" and I was thinking "wait, I thought we are only considering massless particles"...
The thing you forgot to mention is, the Lp only matters, if an object (particle) is considered. For "empty space" this does not apply, at least when if we don't think about vacuum fluctuations at this point.
The other explanation of this I heard was that to understand what's happening below planck length, we need to probe with a quantum particle whose wavelength is smaller. Such a particle has such high energy that its mass equivalent is so dense it forms a black hole with a event horizon that is slightly bigger than Planck length. If we tune things a bit, the point where event horizon size and wavelength of the quantum particle actually meet is exactly the planck length.
An analogy: If you think about your phone screen, the pixel count - and therefore pixel size - is the maximum screen resolution. Smaller pixels same screen size means higher resolution.
The planck length represents the maximum resolution of our universe.
Question: We can’t observe beyond a black hole’s event horizon because time is no longer present?
@@yon5925 We can't observe beyond an event horizon because the escape velocity exceeds the speed of light. Arguably from an outside observer's view time stops at the event horizon as well - so you're right in stating the effect.
@@anthonylittle2396 Ah I see, thank you
Thanks for this.
Here's how to try to picture the size of a Planck Length.
Take a Hydrogen atom (529 × 10^-10 metres!) and magnify it until it is the size of our galaxy (100,000 LY across) then if we zoom right down to our own scale, a Planch length is about the size of a paramecium, and is almost visible!
If that doesn't make your head hurt, then think about this:
We use the speed of light to define time. And we use time to define the speed of light.
Very informative! Before this, I didn't know how the Planck Length was derived, so I learned something new!
I see where several commenters wanted to know the value of the Planck length. If I recall correctly, the universal gravitational constant, G = 6.67 E-11 N m^2 kg^-2, Planck's constant, h = 6.626E-34 Js, h-bar = h/(2*pi), the speed of light, c = 3E8 m s^-1. Thus, the Planck length is 1.61E-35 m.
This number is so small, but sooooo small, that it's in the range of the 10e-5 part of the lowest SI prefix of quectounit, which in turn corresponds to anything multiplied by 10e-35.
Best and simplest explanation I ever heard. This guy must be the best teacher to have
That was awesome ! Thank you so much. As a musician and social worker, I’m fascinated with quantum physics, but have no formal education on the subject. Your explanation of the Planck length may be the first I’ve understood enough to make ‘some sense’ out of the paradoxical world of quantum physics.
Thanks for this. I'm not a scientist or mathematician, and I pick up only what I think is the gist of the argument. Nonetheless I very much enjoy listening and learning, and thinking about how some of these ideas come together in the most fascinating ways.
OMG! This video is the BEST explanation I've ever seen on why the Planck length "may" be the smallest meaningful distance in our universe. The math you used wasn't super-difficult to follow. In this one video, in just a few minutes, you not only explained "why" Planck length is the lower limit on size, you also explained why the Uncertainty Principle doesn't allow us to know both the position and momentum of a particle to the same level of precision, and why quantum physics and General Relativity have not yet been unified in a way that can explain both the very smallest and very largest phenomena in the universe. I just had basic physics and chemistry classes in high school in the 1970's, and my own readings of science-related material since then, so I am 100% a layman, yet everything you said made perfect sense and it was easy to follow your logic and make the connections in my mind that you are trying to teach here. Your students are the luckiest on earth to have you as their instructor.
Really great video, you explained it really easily. I subscribed, keep the good work!
Thanks so much for subscribing! Glad you enjoyed, stay tuned for more!
I never understood this before, but it was explained so clearly that around halfway through the video I was already predicting the end of it.
Thank you!
Glad to hear it!
Exactly what I was looking for! All the other videos, were lacking the very reason this is the smallest length for our physics. Thanks!
Bro did an excellent job. The elegancy can tell he'll be a great physicist.
This is a perfect video! Short and sweet, and genuinely enlightening. As soon as you explained the relationship between mass and measurement it clicked. Thank you
Thanks so much! Glad you enjoyed 😁
Holy crumb, I sorta understood that. I'm serious, this gives me a bit of hope to continue to understand. Thank you/
In signal processing we talk about the Nyquist rate. This is the minimum rate where we can perfectly reconstruct a band limited signal. I’ve always wondered if this could be applied to spatial sampling and solve Xenos paradox.
thank you and finally after thousands of videos somebody made a simple straightforward description apply Planck length has the limit.
Glad you liked it!
Finally somebody not afraid to present the general public with the math to understand higher concepts. Thank you!
I'm glad you ended with acknowledging that we need a unifying theory to know if the Planck length is actually the smallest area OR if it is just our understanding of physics and the math that is breaking down.
Thank you for going through the steps so eloquently! Easy for me as non physicist to understand 👍
Also, since black holes exist, it's clearly not the smallest scale is it?
Planck length makes me feel like we're living in a simulation and the Planck length is the resolution of the system it's running on the same way video games have a finite resolution or accuracy in their engine.
I feel like I owe you tuition. That was a very easy to understand and intuitive way of explaining this concept. This made me look forward to advanced physics classes I will be taking over the next few years. Thank you!
Thank you. I didn't understand theoretical molecular physics before, but after this 9 minute video, I'm pretty sure I got it.
This is as good explanation as I have seen.... I understand it a little better now :)
Thanks so much! Glad you enjoyed it :)
Plank length is the smallest theoretical length you could measure, however you can always divide it down to smaller lengths, they just would not be measurable. In short if you tried to "look" at a plank length you form a plank length black hole that would be at the plank temperature for a plank time and then evaporate.
This is an extremely elegant and to the point explanation of Planck length.
So what you are saying is that on a small enough scale, space is actually pixelated, and time -actually ticks...
Excellent presentation. Although physics is not my chosen field, I am a scientist, and I've studied physics as a hobby for decades. My observation is that the two areas that will push physics to the next level are: 1. A better theory of quantum gravity that can be verified, and 2. A much deeper understanding of what is actually going on with quantum entanglement. The absurd weakness of gravity, and the apparent violation of special relativity by quantum entanglement, are the biggest clues that something important lies just underneath the space-time-matter-energy canvas that all of modern physics is painted on. But whatever theory is suggested to better explain these two phenomena - it has to be testable - that is, if we really want to get to that next level. In my opinion, it is time for a renaissance in physics where we take a hard look at known problems that are today, for whatever reason, largely ignored by the physics community.
Very interesting and explains the Planck length in a way I hadn’t heard before.
wow those presentation skills are stellar! not a single um or pause. and explained in simple terms. you really know what you’re talking about!
Even more interesting when you include Frank Znidarsic's equation to derive plank's constant
This is incredibly dope and do well explained for how complicated the subject could probably be.
just waw, I'm no physicist, but I hear of planck length regularely for 20 years now, and it's the first time I see the math behind it. Astonishing.
A real big tahnk you
I’m thinking you might be the guy who could explain to us how Schrodinger and Heisenberg were able to determine that space was pixelated (not SMOOTH!) at the Planck scale, and why, after making this determination, it caused Schrodinger to comment that, if he had known it would come to this, he would have preferred NOT to have been involved…
I need all the help I can get here!
Fantastic video! Great pace, had to rewind multiple times to fully understand but a lot of information packed into a short video
Question: if Lp, the Planck length, is the smallest something can be, is it also the smallest difference between two lengths? I.e. I can have two particles be 100 Lp apart, but can I have them 100.1 Lp apart?
no , i dont think so
Michael cera is killin it in physics
I love discussing Planck's constants! I'm happy to have found your channel.
That was a very concise explanation, thank you; hope your channel grows 😊
Thanks a lot! Glad you enjoyed 🙂
Ok just found this video. ... Actually the best explanation I've ever heard for plank scale
You have really amazing presentation skills - I am on board :-) Greetings from Vienna!
Thanks for such a kind comment! Glad you enjoyed :)
Thanks for explaining this deliberately in a manner that's easy to process, mate. Cheers...☀
Best explanation I have EVER heard!!!!! - Please make more videos!
This is such a wonderfully well explained video. I actually had this question for a long time and thank god for the RUclips algorithm to suggest this video to me because it answers just that. Thank you.
Thank you! I never understood why you couldn't have a length smaller (or rather, know anything about a length smaller) than the Plank Length. Now I do (as much as I can!)
you're a natural born teacher🙂very well explained, keep it up
Well explained for such a complex subject, like I understood any of it lol But you almost made me feel like I understood something there, I more or less got an idea of what you were explaining. I would only suggest a slightly higher audio next time, it was ok but somewhat a little bit low, but really, great video. Keep it up !
Wow. Let me be one more person who chimes in here and says how well-explained and clear this was.
Thanks a lot, good sir, you've won yourself a subscriber
Now this is a video I've needed for a long time
Why when you find E=PC is rotation included?
I like this explanation, and I think it should give those of us not fully immersed in modern physics some confidence that the Planck length is a real limitation. Maybe it is just a limiyof our models, but the photoelectric effect seems a solid indication of quantum energy, and quantum mass and quantum length come right from that. This really made it easy to understand the connection.
Great brain! What a fascinating video!
Haha, thanks for your comment! Glad you enjoyed :)
This is the first time i have had my questioned answers...which is. "Why could you not have a half planc length?"
Thank You.
Never knew that. Appreciate the education on why it is important.
Finally, an explanation of the Plank length that I can understand! Well done. Subscribed
Now I can measure my Paenus, thank you science man
Thank heavens there is some humor here. 🎉
576 subscribers is *criminal* for such an excellent explanation of the Planck length.
Best explanation even without any fancy visuals. Thank you!
I've seen many explanations of the Planck length, and yours is the 1st I've grokked. Your use of word atom is very appropriate, as in Greek it means indivisible.
But the atom has been divided.
This is a great video. It really did clear a lot up for me, turns out I’ve been staring at this length my whole life!
Excellent, very accessibly conveyed stuff!
good job young man! and all explained in a short time!
Shout out to Max Planck who discovered this constant by accident, using a mathematical hack to solve the "ultraviolet catastrophe". He basically said "let's pretend that energy comes in quanta" and suddenly all the problems with our understanding of blackbody radiation disappeared. He expected his Planck value to be precisely zero, and that the problem was measurement, but it wasn't zero, it was very slightly above zero, so what he actually did was to discover quantum mechanics.
The "let's pretend" method of discovery is wonderful. Euler did a similar thing when discovering complex numbers. He basically said "let's pretend there's a solution to the square root of -1, and we'll call that number i" and in doing so, previously unsolvable equations were now solvable.
I just found your channel. I look forward to what you do in the future as I’ll be back at university in the spring finishing my physics degree. Good luck!
Thanks for this explanation. I could understand the big parts. Thank you
That was a really good physical and mathematical derivation of the existance of the Planck length for me whon doesn't have a background in quantum physics.
Thanks for great explanation! We need now one about Plank Energy.
Hi!😊
I love physics but I have always been not good at math, but it never stops me to be interested and it's awesome!!❤🧠 Thanx for your video.👍👍👍👍
Very well-articulated, thank you.
Wow bro u explained in a very simplk manner ❤️ love you as a human being ❤️ love from India
Thank you very much! I hope you enjoy future videos :)
Thanks for putting that all together for me. I was familiar with the concept but not the "why". Now I know. The math is actually fairly simple which is the biggest surprise of all.
This might be an almost obscene question under such a video, but could someone explain to me, why at 6:00 the substitution of E with mc^2 makes m>h^2/(l^2*c^2) instead of just m>h^2/l^2 ? Total physics/maths noob here, I'm wondering on an algebraic level...
Very good explanation, thank you!
Thanks for watching! Glad you enjoyed :)
That was beautifully explained! Natural born teacher.
That was lovely- incredible to see such fundamental equations combined- it all seems so easy when you know