@@OrdenJust without any energy gradient, "energy" is meaningless. Remember, "energy" doesn't actually exist, it's a property. It's a number. It only has meaning in relation to a gradient.
Fun fact: Mass doesn't require mass! A single photon has no rest mass, however if you have two photons with opposite momenta, the system of both photons together has rest mass.
The rest mass of the resulting particle in said collision isn't a photon, you've converted energy in the form of two photons temporarily (or permanently) into matter; mystery solved. Look up "Two photon physics" if you don't take my word on it (which you shouldn't)
@@dibyajyotibharadwaj8129 A better way to say it is that mass is an emergent property - not a property of individual things but of a system as a whole. While it might seem like a property of individual objects, that's only because what we think of as individual objects are actually incredibly complex systems of particles. It's the interactions between the particles that result in mass. If you're interested in how this happens, PBS Spacetime did a really amazing video about it a few years ago called "The Nature of Matter and Mass." Nick also did a video about it called something like "What if you were made of photons?!"
My understanding of this (in my crude understanding) was that photons do not have rest mass, but do have relativistic mass. A single photon can never be at rest, so the lack of rest mass can never be observed in reality. On the other hand, two photons moving in opposite directions, the velocity vectors cancel each other out, so the average mass of the pair is at rest even though none of the individual photons are actually at rest.
Hi! I think it was a lot easier to show this using energy-momentum relation, using: since the mass term is 0 I wont write it out, and I take the sqrt and we get: E = pc (since the mass term is 0 I wont write it out) then using incredibly simple algebra, p = E/c
I actually remember learning in my engineering courses that F = ma is technically not the formal definition of Newton's Second Law, that the proper way of saying it is F = dp/dt. The reason we generally use F = ma is because d(mv)/dt = ma for objects of constant mass. Granted, the example they generally use to illustrate this discrepancy is objects with varying mass, like rockets, which would give d(mv)/dt = ma + v(dm/dt). The fact that light has momentum without mass may have been mentioned in passing, but brushed off as irrelevant for our purposes.
The full equation relating energy to momentum is: E^2 = (pc)^2 + (mc^2)^2 Where: E is the total energy of the system. p is the momentum magnitude. c is the speed of light. m is the invariant (or rest) mass. If p (momentum) = 0, (pc)^2=0, and the equation simplifies to E=mc^2. If m (mass) = 0, (mc^2)^2=0, and the equation simplifies to E=pc. Rearranging for p gives p=E/c.
Our school teacher recommended to watch your video! Your way of explaining complicated things is so interesting to listen. Thank you, Nick! You got a new subscriber all the way from Kazakhstan!
Hehe, just watched this video on my own, countrymate (is there a word like that?). He could have summed it all up using this formula: (m*c^2)^2=(m0)^2*c^4+p^2*c^2, where m is referring to relative mass and m0 is rest mass. Since photon has no mass the first term on the right is zero and formula is reduced to the formula he showed for photon momentum.
I’d love to see some quantum biology videos. Examples: how enzymes use quantum tunnelling, how smell may be triggered by the wave properties of molecules, how some birds use entanglement to coordinate while migrating. These are things that not a lot of science education youtubers have talked much about.
@@waynelin5916 But what about the gravitational field? The gravitational field exerts a force. Should not it then have momentum? And if that is the case, then what is the equation for gravitational momentum?
@@waynelin5916 Wait, never mind. Let us say that we have two objects attracted to each other by the gravitational force. When the gravitational field exerts a force F on one of the objects, it also exerts a force -F on the other object. The total change in momentum of the two objects is dp=dp_object 1+dp_object 2=F_object 1•dt+F_object 2•dt=F•dt-F•dt=0. According to conservation of momentum, the change of the momentum of the gravitational field is also 0. Thus the momentum of the gravitational field is constant, and then I guess it makes sense to let the momentum be zero always (i.e. the gravitational field has no momentum).
This is good stuff! Might I suggest a video on the difference between energy and momentum? We learn conservation rules about both, so why do we need both concepts? Might marry up well with Noether's Theorem.
I think you're mixing up two concepts that are difficultly intertwined. But there are several quantum fields that permeate through the universe and Bosons are seen as the force carriers that represent a change in the field, e.g. if you take an interaction between two electrons, the electromagnetic field is changing between them and a photon is the force carrier that represents the change in energy through their collision. To help you clear up how force is related to the momentum of light in his video if we take his equation for momentum of the speed of light p = E/c : E being energy which is Force times velocity then p = (F*v)/c and if we take the speed of light as v they cancel out and the momentum is equal to the force of the light particle: p = F
@@The_stone_Philosopher Except that you've replaced E, energy, with F•v, dot product of force & velocity, which is power = a rate of change of energy. Multiplying the RHS by ∆t (and converting momentum to change of momentum) remedies that dimensional mismatch: ∆p = (F•v/c) ∆t , then with v = c, ∆p = F ∆t which, in the limit as ∆t→0, becomes the more familiar F = dp/dt Fred
**YOU SHOULD HAVE YOUR OWN TV SHOW** Really good cheerful presentation. Contact the companies who make cartoons and the TV show syndicators and keep knocking on the door until you get your own show. Not sure a radio show would work. The performance is pretty visual. Greatest value is video. Until I watched your videos, it was not clear that science could be so entertaining. . . .
@@alexandrumoise1511 Probably depends on the demographic as to choosing the right venue. My point was, if you look at the other youtube science videos, it's pretty hard to find an entertaining undertone while still pulling off accurate science that is understandable for average person. If you look at his video on the Poynting vector, it's a great example of making an esoteric and mostly conceptual issue entertaining. I guess my main point was, he's got talent, is very good at making the science entertaining, especially when talking to his 'identical twin' and more people should benefit from it, and sure of course find the right venue. . . .
@@Greg_Chase yeah, I agree. But I also think that working in a more professional environment, although allowing for higher quality video/effects, and more content, would also decrease authenticity and free expression. I like his style and personality, and I like the free way he makes these videos. If he could make a living by doing this I think that would be ideal. I think by adhering to a network there will be more filters between his mind and mine. And I dislike that. Just my opinion.
@@JohnSmith-lf8ks I'd like to see a video on imposing order on the background field, aka 'coherent superposition', how the declining inertia gradient around planets (what we call gravity) works, and how to use a coherent superposition device to shield inertia, neutralize gravity, and hover. I'm building one, a very simple one, a small one, and he'd do a great job of presenting the nuts and bolts. He'd do a great job explaining how inertia is created when the atoms of matter objects interact with the background field. The video would start with the fact that accelerometers do not work in the 9.8m/s^2 acceleration due to gravity, and how Einstein in 1905 told everyone "inertia - mass - is variable, it is not fixed. The inertia (mass) of an object that is **accelerating** to light speed increases greatly. The MATTER, the atoms, of the object do NOT increase; the inertial mass increases. The acceleration results in increasing inertia, like all accelerating actions do, and inertial mass grows immensely and makes light speed the maximum velocity. Mass is not FIXED. Mass is variable." He would pull that off and a lot of problems on the planet would fall away. It's a rare person who can get rigorous explanations across with a humorous entertaining quality to it. Look at his video for the Poynting Vector *after* you've looked at some of the other Poynting Vector videos. . . .
I always found this helpful: E=.5mv^2 If you differentiate wrt v, you get that the rate of change of energy is the momentum. If its just rate of change of energy, then its easy to understand it exists in many forms and requires neither mass nor velocity. It also follows that the conservation of momentum must hold for the conservation of energy to be true. If the momentum isn't conserved, then neither is the energy. Same deal with force.
Thanks for another great video. I'm always impressed by how well you explain things. However, one thing I'm still unsure of is what the definition of momentum actually is. Is there a standard definition or is it different in different circumstances? What does it mean for something to have momentum? Is it ∫F dt?
Yes, ∫F dt is how I'd define momentum mathematically. We have to come up with names for measurements pretty early on. Unfortunately, that means we usually name things before we realize what they _actually_ are.
@@matthewking3326 Almost: For a _constant_ force, it would have to the size of the force applied in a given amount of time times the amount of time. You have to multiply by time in order for the units to work out. For non constant forces, we have to take the integral of force with respect to time instead of just multiplying.
Graphene is simply a conductor. Not a good one like most metals are, but the word semiconductor points mostly to materials that can be doped to become P or N and, o its okay
So if I shoot laser to a mirror, light that is reflected has lower energy than light that went in since it gave some of its energy as a push to the mirror? So if I will have a mirror at reletavistic speed, I will blueshift all the mirrored light?
Like, in light-years? Yeah, I've had that video on the list for a while, but it never gets made. I just keep getting _more_ excited about other topics.
@@ScienceAsylum There was another term for it aswell, parsecs. Brings that up aswell, if you do the video. Also, do any pet theory on how space navigation will work(you can make that a separate video if you want, possibly as a follow up to the previously mentioned one.) There's bound to be tons of trigonometry like for the globe there is the Haversine formula - en.wikipedia.org/wiki/Haversine_formula , but for space I imagine it will be pretty tough even looking at constellations as they'll undoubtedly look pretty different from any other points in space that's isn't earth.
Ever since (50yrs ago) when I learnt about solar wind pressure known to Chinese long ago.. I put this fact on the back burner as had no time to bother. Today u brought it to the front burner and solved it. Very enjoyable. Thanx.
OH thanks, I've been asked this question about "how does light can have momentum if it does not have a mass ?" and I did not find a proper way to explain it. Your videos are very interesting, clear and short :) !
Ha! I never got it until now!! Its almost absurd hów totally cléar that man can teach! Even the most confusing things he can explain só totally clear and understandable! Yes, Nick Lucids Science Asylum ís a fenonem through wich thru knowledge did and dó wide spread over the internet, so over mankind!!
Regarding that question at the end, to capture visible light with an antenna would require a very, very short antenna, right? I think iridescent butterfly wings and feathers have physical features that might be the appropriate scale.
Best science instruction. If only you’d been around much earlier in my life-and the lives of many others, misled by short-sighted, condescending simplifications. Thank you.
I have to watch most of your Videos a few times, and every time I am detecting a bit more of intrestig and meanigfull information. Finally - I sould have understand it completly, well I should...
Momentum is just the total energy or the total force. Force/energy hasn’t necessarily mass, so momentum hasn’t either, but if we want to measure that momentum we will have to interact with it and create mass...
@@benjaminmoszkowicz8149 Energy must have mass or momentum or both. The mass is not created by measuring it. It is just another way to express the total energy.
Ronald de Rooij no, otherwise photons would have mass, but they don’t, they do have energy.... Mass and energy are related, but they aren’t the same thing!
I didn't saw the video yet, but the title is inquiring. Now I understand what you said, that the Patreon support allow you to make what has to be done and not click baits.
Will you cover electrodynamics in the near future? Everyone would enjoy your insights on basics like Electrostatics, Gauss' Law, Field, Dipoles, Current Electricity, AC, Capacitance, Conductors, Magnetism, etc
I'm interested in how a single photon carries momentum, particularly with regard to direction. Since the direction is quantized, it would seem momentum would need to be up or down (or right/left, etc.). This also seems needed to maintain causality since otherwise, a clever arrangement of lenses could send information into the past. (Momentum shifting light from a distant star would affect that star years ago when it emitted the light.) So is it only in aggregate that photons have reasonable directional momentum? Something weird seems to be happening.
both are 2 completely independent equation derivatived from diferent places. p=E/c come from E=mc² or E²=(mc²)² (pc)² and there is another for quantum mechanics p=h/λ
OK, *finally* a video that actually does explain how photons can have momentum. (Fourth time's the charm; the first 3 videos I watched with titles promising to explain how/why photons have momentum were dumbed-down fluff that explained nothing.) Thank you for *not* being afraid to mention vector cross products, Maxwell's equations, Poynting vectors, etc. Thank you for *not* dumbing this down. Now I have a better understanding of what momentum is and why photons have momentum.
Some of the confusion probably comes from the fact that we always write the equation as p=mv, implying that momentum is some emergent property of mass and velocity. Momentum is fundamental to an object, so it might be better written as v=p/m, as velocity can be described as the thing that changes when you apply momentum to an object with mass. For the special case of slow-moving objects with rest mass.
@@ScienceAsylum Well what I like even more is that my 14 year old son understands this stuff and gets more clarity than some of the high school things he learns. Keep up the great on these complex areas!
Excellent. They should show this video at high school in physics. In the old days my physics teachers could not / did not explain momentum like so clear, … and later at university they either tell you that you had had the basics at school OR that anything you had heard at school was wrong and now you get the real thing, but seldom lecturers addresses the misconceptions (which was created earlier) in itself. It took me quite some focus and headaches to get rid of the wrong argument. Somehow if one is not immediately aware of a conflict between better and worse explanations, wrong arguments gain a life on their own and live a ghostly shadow existence (maybe because of wrong authorities, stress or inflexibility ?) until you force them to clash.
Your videos are awesome, I just wanted to poynt (:D) out something: 2:31 - This works fine for objects with 0 mass because they are moving always by v=c, so gamma goes to infinity but, gamma*m*v stays finite and = E/c, so, no, it doesn't fail for light
4:54 'The fields are static.' Were the metal plates statically charged or carrying a charge? If you have a square with two magnets and two statically charged plates there's energy? Momentum, ie, moving energy?
The metal plates are statically charged, yes. The charge is not moving. You could say that energy flow (from the Poynting vector) is the "motion" for that momentum.... but now you're talking about a made-up thing (energy) rather than a physical thing (like matter).
Hey, I have different one: 4:09 - If that's electromagnetic wave, why they're in phase? I've seen similar animation in other places as well and that confuses me A LOT. From what I've been told, peek of magnetic wave should be on the most change of electric wave. And the other way around. It should give electric and magnetic wave to be shifted by 90 degrees between each other, not in perfect sync. So why animation like this here?
So momentum is the integral of the sum of the forces on an object. Got it. But what exactly is a FORCE? I thought it was basically the application of energy, but I'm not sure that's right. This video really got me thinking about physics and calculus and now I really want precise definitions of force and power. I'm going to have to look into more, which is good because it'll give me head start for my physics class next semester.
@@ScienceAsylum link to the video? I have the same exact question I don't understand fundamentally the concepts of force and momentum, their definitions seem arbitrary to me
4:30 Wait, wait, wait. I get that momentum doesn't require mass, since it's more fundamentally related to energy and mass is just one type of energy. I can even get behind momentum not requiring velocity, since it's more about exchanging forces and it makes sense that fields can do that without having velocity per se, since velocity is a property of particles. But how can there be an exchange of forces if the fields aren't even _changing_ in any way? That doesn't make any sense to me. What am I missing?
Your reasoning is sound. Remember, _having_ momentum doesn't mean that forces are being exchanged. It just means that they _could_ be exchanged. I can't think of an EM scenario where momentum is conserved but the field doesn't change.
Important question What force pushes light particles from its source to its surroundings? Like the sun has light but what makes that light travel to us on earth?
*"What force pushes light particles from its source to its surroundings?"* Steady velocity is the natural state of motion. No force is necessary to move at a steady velocity. You only need forces to speed up, slow down, or change direction.
@The Science Asylum I was thinking about metals recently like why they produce "metallic" sound when hit with something... Other properties of metal can be explained by electron sea theory like shiny nature of metal, malleability, electricity and heat conduction etc. But I couldn't find any good explanation for why they produce "metallic" sound.. If you could explain it, it would be tremendously helpful..
I am no expert at this, but hitting something produces a short peak of force. To construct such a peak from harmonic frequencies means that there is a large spectrum of them. And some of those frequencies will match the resonant frequency of the metal object, which means it will resonate for a while until it dissipates all the energy to air, and produce a distinguished fading sound. That is how I explain it at least...
Another excellent video, really enjoy your channel. But I’m surprised you did not comment about the vector nature of momentum. How each component of momentum (x,y,z) is independently conserved
How are orbits of stellar objects continuous collisions? What's the difference between momentum and inertia? Do we get better solar sails from mirrors or vantablack? This video raises more questions than it answers! Which I love. But also hate. I hope you have a lot of follow up videos planned.
The momentum of those orbiting objects is continuously changing. They are continuously exchanging momentum with each other. That exchange in momentum is related to the force of gravity between them.
Can you do a video on how wheels work? It might sound like a trivial question, but I still have questions like “Why don’t wheels speed up indefinitely if friction is in the direction of movement?”. Please don’t refrain from including details.
Please consider answering this question: According to special relativity, if an object with mass reaches the speed of light, time stops for it. Because light has no mass, does special relativity not apply to it? Light takes time to travel from Sun to Earth. What is your opinion on that?
For the sake of the models? Yes. However, theoretical physicists are not the ones deciding what the base units are. Experimental scientists do that and they have different priorities. The base units are set up to be the things we imagine ourselves measuring directly in experiments. No one measures momentum directly.
So, maybe I’m off base here, but could you propel a space ship with a rail gun? Of course firing a projectile would have an opposite force on the ship, but what if you fired the rail gun with no projectile? Would that still propel the ship in the opposite direction? It creates a magnetic field, and as it moves toward the opposite end, would it want to stand still and move the ship instead? Your discussion spawned this idea in my head.
Well, whether or not a rail gun would even work without a projectile in it would depend on the design. Some designs require the projectile to close the circuit. Assuming, that's _not_ the case, there's only one way that would work to push a ship forward. You'd have to make sure the EM field changes the rail gun was creating released momentum in a particular direction. If you manage that, what you've create is light (maybe not visible light, but light nonetheless). That light behaves just like the projectile would have and momentum must be conserved. Whether or not you get a _noticeable_ thrust will depend on how much light you generate (spoiler alert: it needs to be _a lot!_ ).
The Science Asylum yes that makes a lot of sense. I suppose you’d wind up with electrical plasma drive, which is already being tested. It doesn’t have much thrust, but can run for a long time, which is its advantage. I’m thinking more of a ship that generates a magnetic field around it, starting at the front, the field moves to the rear, over and over. Would the magnetic field want to stand still, and push the ship forward inside the field? Or would it have no effect? Kind of like having a fan on a boat blowing into the sails, the opposite effects cancel each other out. As far as a rail gun, if you shot actual projectiles it would push the ship, but you’d eventually run out of projectiles. Thank you for the reply! Love the channel, always thought provoking!
Just generating a magnetic field (single-handedly) would have zero effect on the motion of the ship. If it were strong enough to deflect solar wind, it could pick up momentum from those particles gradually over time... but I imagine the power requirements for a field that strong would be absurd.
The Science Asylum thank you for the response! And yes I see your point. I’m thinking of a Mag Lev train, but the magnets have something to push against, and you can’t push against space, apparently. You’d need anti-gravity to push you through space, which is very different from a magnetic field. And, hasn’t been invented yet, so there’s that. Love the channel!
I love your videos! However, how does light exert a force if it's only a wave? Or particle? I'm not really sure I think both but I know for sure it's just energy so how can that physically push stuff?
Thanks again for the videos! I've got 2 questions that have been bugging me: 1) Is there an upper limit for sound frequecy in Earth's atmosphere? Google hasn't helped me. 2) why does the observable universe look so uniform, if light has taken different amounts of time to get to us the further out we look?
1) yes. we haven't reached it but it is estimated to be between 3-5GHz. The problem is the larger waves only go very very short distances before being absorbed. Remember a sonic boom, is typically below 100hertz. and the limit is estimated at 3000-5000hertz. 2) our eyeballs are both right next to eachother for us to gauge distance. Those stars you see in the sky actually aren't as uniform as you think; the difference in the brightness between stars is used to tell how far they are; it is more complicated than that but hope I gave an idea to think on.
Momentum: ability to exert a force
Energy: ability to do work
Indeed! This parallel is not a coincidence.
It seems to me that for a closed system in which entropy is at a maximum, the closed system can have energy, but no ability to do work.
@@OrdenJust no energy gradient though.
@@OrdenJust without any energy gradient, "energy" is meaningless. Remember, "energy" doesn't actually exist, it's a property. It's a number. It only has meaning in relation to a gradient.
Can we say that momentum and energy has the same abstract property?
I clicked fast fast.
So, lot's of momentum...
@@_Arminius but... Momentum doesn't requires velocity...
@@MTheoOA Yes, that was the joke.
@@_Arminius Yeah, i made a joke inside your joke
Whatever you clicked on felt a lot more umph! than usual
Fun fact: Mass doesn't require mass! A single photon has no rest mass, however if you have two photons with opposite momenta, the system of both photons together has rest mass.
Bro can you explain nicely
The rest mass of the resulting particle in said collision isn't a photon, you've converted energy in the form of two photons temporarily (or permanently) into matter; mystery solved. Look up "Two photon physics" if you don't take my word on it (which you shouldn't)
@@dibyajyotibharadwaj8129 A better way to say it is that mass is an emergent property - not a property of individual things but of a system as a whole. While it might seem like a property of individual objects, that's only because what we think of as individual objects are actually incredibly complex systems of particles. It's the interactions between the particles that result in mass. If you're interested in how this happens, PBS Spacetime did a really amazing video about it a few years ago called "The Nature of Matter and Mass." Nick also did a video about it called something like "What if you were made of photons?!"
WTF
My understanding of this (in my crude understanding) was that photons do not have rest mass, but do have relativistic mass. A single photon can never be at rest, so the lack of rest mass can never be observed in reality. On the other hand, two photons moving in opposite directions, the velocity vectors cancel each other out, so the average mass of the pair is at rest even though none of the individual photons are actually at rest.
Once again you have taken a complex idea and made it easily understandable to most people .. from a retired Physics Teacher!! Awesome!
Hi! I think it was a lot easier to show this using energy-momentum relation, using:
since the mass term is 0 I wont write it out, and I take the sqrt and we get:
E = pc
(since the mass term is 0 I wont write it out)
then using incredibly simple algebra,
p = E/c
@@nahimafing amazing
"Momentum does NOT require Mass!!"
Therefore, momentum is not Catholic.
My logic is flawless...
you are everywhere.
But Momentum DOES require force!
Therefore, momentum is Jedi.
Checkmate
@@CaptTerrific You may think you have the high ground. But force times velocity is power. And you underestimate my power!
Come to the dark (matter) side!
Your logic is immaculate.
I actually remember learning in my engineering courses that F = ma is technically not the formal definition of Newton's Second Law, that the proper way of saying it is F = dp/dt. The reason we generally use F = ma is because d(mv)/dt = ma for objects of constant mass. Granted, the example they generally use to illustrate this discrepancy is objects with varying mass, like rockets, which would give d(mv)/dt = ma + v(dm/dt). The fact that light has momentum without mass may have been mentioned in passing, but brushed off as irrelevant for our purposes.
Me in middle school reading your comment
👁. 👁
👄
F = dp/dt is all well and good, but what is p then? Oh, I see ∫Fdt = ∫dp, but what is p then?
@@DumbledoreMcCracken p is the conventional symbol for momentum in physics. The p comes from Latin.
@@OptimusPhillip You see what I did? Work is ∫Fds. Momentum is ∫Fdt.
lol just learned this. btw I shouted you out to my teacher, he said your vids are great.
Awesome!
@@ScienceAsylum Hi, can you make a video about color charge? :)
Life is a lie
@@phamminhduc0609 ...and youtube comments are
@@diogoandre756 yea that wud be good
The full equation relating energy to momentum is:
E^2 = (pc)^2 + (mc^2)^2
Where:
E is the total energy of the system.
p is the momentum magnitude.
c is the speed of light.
m is the invariant (or rest) mass.
If p (momentum) = 0, (pc)^2=0, and the equation simplifies to E=mc^2.
If m (mass) = 0, (mc^2)^2=0, and the equation simplifies to E=pc.
Rearranging for p gives p=E/c.
Our school teacher recommended to watch your video! Your way of explaining complicated things is so interesting to listen. Thank you, Nick! You got a new subscriber all the way from Kazakhstan!
Hehe, just watched this video on my own, countrymate (is there a word like that?). He could have summed it all up using this formula: (m*c^2)^2=(m0)^2*c^4+p^2*c^2, where m is referring to relative mass and m0 is rest mass. Since photon has no mass the first term on the right is zero and formula is reduced to the formula he showed for photon momentum.
Very nice! High five!
3:13 I imagined a bunch of tiny people dressed like Isaac Newton running around and pushing things
HAHAHA
I’d love to see some quantum biology videos. Examples: how enzymes use quantum tunnelling, how smell may be triggered by the wave properties of molecules, how some birds use entanglement to coordinate while migrating. These are things that not a lot of science education youtubers have talked much about.
Man,your talent is real,your videos really hook me up with physics!
Thanks!
So, its defined the other way around.- anything that can exert a force has momentum. 🤔
Yes.
@Andrew H Spacetime doesn't exert force.
@@waynelin5916 But what about the gravitational field? The gravitational field exerts a force. Should not it then have momentum? And if that is the case, then what is the equation for gravitational momentum?
@@waynelin5916 Wait, never mind. Let us say that we have two objects attracted to each other by the gravitational force. When the gravitational field exerts a force F on one of the objects, it also exerts a force -F on the other object. The total change in momentum of the two objects is dp=dp_object 1+dp_object 2=F_object 1•dt+F_object 2•dt=F•dt-F•dt=0. According to conservation of momentum, the change of the momentum of the gravitational field is also 0. Thus the momentum of the gravitational field is constant, and then I guess it makes sense to let the momentum be zero always (i.e. the gravitational field has no momentum).
@@ScienceAsylum You do realize that force requires mass 'f=ma'
This is good stuff! Might I suggest a video on the difference between energy and momentum? We learn conservation rules about both, so why do we need both concepts? Might marry up well with Noether's Theorem.
Already working on it :-)
Might as well do momentum vs energy...
Me and my mom watch these videos every day at lunch, they are awesome!!!
That's great!
That's some nerdy mom in my opinion. I am trying to get my wife into science. But no she isn't even budging :(
What are bosons and how are they "carrying a force" when the force is just change in the momentum
I think you like QED and QCD. Not easy stuff, though.
I think you're mixing up two concepts that are difficultly intertwined. But there are several quantum fields that permeate through the universe and Bosons are seen as the force carriers that represent a change in the field, e.g. if you take an interaction between two electrons, the electromagnetic field is changing between them and a photon is the force carrier that represents the change in energy through their collision.
To help you clear up how force is related to the momentum of light in his video if we take his equation for momentum of the speed of light p = E/c : E being energy which is Force times velocity then p = (F*v)/c and if we take the speed of light as v they cancel out and the momentum is equal to the force of the light particle: p = F
@@The_stone_Philosopher Except that you've replaced E, energy, with F•v, dot product of force & velocity, which is power = a rate of change of energy.
Multiplying the RHS by ∆t (and converting momentum to change of momentum) remedies that dimensional mismatch:
∆p = (F•v/c) ∆t , then with v = c,
∆p = F ∆t
which, in the limit as ∆t→0, becomes the more familiar
F = dp/dt
Fred
Bosons are quantum particles
**YOU SHOULD HAVE YOUR OWN TV SHOW**
Really good cheerful presentation. Contact the companies who make cartoons and the TV show syndicators and keep knocking on the door until you get your own show.
Not sure a radio show would work. The performance is pretty visual. Greatest value is video.
Until I watched your videos, it was not clear that science could be so entertaining.
.
.
.
TV is dead.
If he could have a well funded internet show... Now that would be ideal.
@@alexandrumoise1511 Probably depends on the demographic as to choosing the right venue. My point was, if you look at the other youtube science videos, it's pretty hard to find an entertaining undertone while still pulling off accurate science that is understandable for average person.
If you look at his video on the Poynting vector, it's a great example of making an esoteric and mostly conceptual issue entertaining.
I guess my main point was, he's got talent, is very good at making the science entertaining, especially when talking to his 'identical twin' and more people should benefit from it, and sure of course find the right venue.
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@@Greg_Chase yeah, I agree. But I also think that working in a more professional environment, although allowing for higher quality video/effects, and more content, would also decrease authenticity and free expression.
I like his style and personality, and I like the free way he makes these videos. If he could make a living by doing this I think that would be ideal.
I think by adhering to a network there will be more filters between his mind and mine. And I dislike that.
Just my opinion.
His style does not work for me. Too much in your face. Also tired of all videos having the same sort of 'great edit and cut'.
@@JohnSmith-lf8ks I'd like to see a video on imposing order on the background field, aka 'coherent superposition', how the declining inertia gradient around planets (what we call gravity) works, and how to use a coherent superposition device to shield inertia, neutralize gravity, and hover.
I'm building one, a very simple one, a small one, and he'd do a great job of presenting the nuts and bolts. He'd do a great job explaining how inertia is created when the atoms of matter objects interact with the background field. The video would start with the fact that accelerometers do not work in the 9.8m/s^2 acceleration due to gravity, and how Einstein in 1905 told everyone "inertia - mass - is variable, it is not fixed. The inertia (mass) of an object that is **accelerating** to light speed increases greatly. The MATTER, the atoms, of the object do NOT increase; the inertial mass increases. The acceleration results in increasing inertia, like all accelerating actions do, and inertial mass grows immensely and makes light speed the maximum velocity. Mass is not FIXED. Mass is variable."
He would pull that off and a lot of problems on the planet would fall away.
It's a rare person who can get rigorous explanations across with a humorous entertaining quality to it.
Look at his video for the Poynting Vector *after* you've looked at some of the other Poynting Vector videos.
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Discovered your channel. Subscribed and digging the blackhole videos.
U kept digging until u made a black hole urself 😂
I always found this helpful:
E=.5mv^2
If you differentiate wrt v, you get that the rate of change of energy is the momentum.
If its just rate of change of energy, then its easy to understand it exists in many forms and requires neither mass nor velocity.
It also follows that the conservation of momentum must hold for the conservation of energy to be true. If the momentum isn't conserved, then neither is the energy.
Same deal with force.
☝
Thanks for another great video. I'm always impressed by how well you explain things.
However, one thing I'm still unsure of is what the definition of momentum actually is.
Is there a standard definition or is it different in different circumstances?
What does it mean for something to have momentum?
Is it ∫F dt?
Yes, ∫F dt is how I'd define momentum mathematically. We have to come up with names for measurements pretty early on. Unfortunately, that means we usually name things before we realize what they _actually_ are.
@@ScienceAsylum So would it be reasonable to define momentum of an object as "the size of the force applied in a set time when the object 'collides'"?
@@matthewking3326 Almost: For a _constant_ force, it would have to the size of the force applied in a given amount of time times the amount of time. You have to multiply by time in order for the units to work out. For non constant forces, we have to take the integral of force with respect to time instead of just multiplying.
Man.. this is one of the best channels on TH-cam but sometimes your high energy just burns me out. It’s too intense.
Fair complaint.
You are really original. Thank you for sharing your knowledge.
It takes a crazy person to explain the world so clearly. Thank you for all your hard work! 8)
Can you talk about super conductors?
@@burakanilince it conducts well if i remember
Graphene is simply a conductor. Not a good one like most metals are, but the word semiconductor points mostly to materials that can be doped to become P or N and, o its okay
atm12 You bet!
Leonard Bernstein, Leopold Stokowski, and Seiji Ozawa are all SUPER Conductors!
Three words: twisted graphene superconductors
The best video I've found to explain what Momentum actually is, and why it doesn't require mass.
AAAHHHH!! the pointing vector video is back to haunt our dreams Crazies! ⏩👻⏩
and it's poi(/y)nting at YOU! :D
So if I shoot laser to a mirror, light that is reflected has lower energy than light that went in since it gave some of its energy as a push to the mirror?
So if I will have a mirror at reletavistic speed, I will blueshift all the mirrored light?
yes, and redshift
less energy lower the frequency, lower the frequency goes to red light.
could you make a video on how to measure distances in space?
Like, in light-years? Yeah, I've had that video on the list for a while, but it never gets made. I just keep getting _more_ excited about other topics.
@@ScienceAsylum
There was another term for it aswell, parsecs. Brings that up aswell, if you do the video.
Also, do any pet theory on how space navigation will work(you can make that a separate video if you want, possibly as a follow up to the previously mentioned one.)
There's bound to be tons of trigonometry like for the globe there is the Haversine formula - en.wikipedia.org/wiki/Haversine_formula , but for space I imagine it will be pretty tough even looking at constellations as they'll undoubtedly look pretty different from any other points in space that's isn't earth.
How about this? th-cam.com/video/QXfhGxZFcVE/w-d-xo.html
Cody th-cam.com/video/dCSIXLIzhzk/w-d-xo.html
Ever since (50yrs ago) when I learnt about solar wind pressure known to Chinese long ago.. I put this fact on the back burner as had no time to bother. Today u brought it to the front burner and solved it. Very enjoyable. Thanx.
Thank you so much for this video! It really makes it easier to understand this, in my opinion, complex topic!
Enjoyable, informative video on a subject not covered much. Well done.
A new video? I couldn't click fast fast enough
Thanks, very nice, clarifies very simply - complicated notions - for knowlegeable vewers!
After watching this video if someone asks me what is momentum??
Me:Ahhhhhhhhhhhhhhhhh!
OH thanks, I've been asked this question about "how does light can have momentum if it does not have a mass ?" and I did not find a proper way to explain it. Your videos are very interesting, clear and short :) !
Ha! I never got it until now!!
Its almost absurd hów totally cléar that man can teach! Even the most confusing things he can explain só totally clear and understandable! Yes, Nick Lucids Science Asylum ís a fenonem through wich thru knowledge did and dó wide spread over the internet, so over mankind!!
Ah. "fenonem" = _phenomenon._
Regarding that question at the end, to capture visible light with an antenna would require a very, very short antenna, right? I think iridescent butterfly wings and feathers have physical features that might be the appropriate scale.
Thanks for your video, I find this subject intriguing.
I love your creativity. Awesome! 👍
hi, please reduce the volume of the background music, thanks
Best science instruction. If only you’d been around much earlier in my life-and the lives of many others, misled by short-sighted, condescending simplifications. Thank you.
You're welcome :-) Glad you like my work.
I was just wondering this last week and also why f equals ma instead of f equals mv
I have to watch most of your Videos a few times, and every time I am detecting a bit more of intrestig and meanigfull information. Finally - I sould have understand it completly, well I should...
why not talk about the formula for momentum the relativistic one which accounts for both mass and massless objects?
I believe he covered it here-
th-cam.com/video/XkPudRiWspc/w-d-xo.html
Thanks 👍👍👍, I really enjoy the way you teach! Greetings from Buenos Aires!
Momentum doesn't require mass but inertia does and that's probably the trip up for most people.
Momentum is just the total energy or the total force. Force/energy hasn’t necessarily mass, so momentum hasn’t either, but if we want to measure that momentum we will have to interact with it and create mass...
@@benjaminmoszkowicz8149 Energy must have mass or momentum or both. The mass is not created by measuring it. It is just another way to express the total energy.
Ronald de Rooij
no, otherwise photons would have mass, but they don’t, they do have energy....
Mass and energy are related, but they aren’t the same thing!
I didn't saw the video yet, but the title is inquiring. Now I understand what you said, that the Patreon support allow you to make what has to be done and not click baits.
Consider me motivated...by momentum. The Science Asylum is capable of exerting such force.
Will you cover electrodynamics in the near future?
Everyone would enjoy your insights on basics like Electrostatics, Gauss' Law, Field, Dipoles, Current Electricity, AC, Capacitance, Conductors, Magnetism, etc
I have a whole playlist: th-cam.com/play/PLOVL_fPox2K9MtRv68T_cmWwQUbg9YR4F.html
I'm interested in how a single photon carries momentum, particularly with regard to direction. Since the direction is quantized, it would seem momentum would need to be up or down (or right/left, etc.). This also seems needed to maintain causality since otherwise, a clever arrangement of lenses could send information into the past. (Momentum shifting light from a distant star would affect that star years ago when it emitted the light.) So is it only in aggregate that photons have reasonable directional momentum? Something weird seems to be happening.
Is there a general version of the equation that reduces to either p=ymv or p=E/c depending on the rest mass?
both are 2 completely independent equation derivatived from diferent places.
p=E/c come from E=mc² or E²=(mc²)² (pc)²
and there is another for quantum mechanics p=h/λ
I've added my finest Hebrew Subtitles/CC yet again! I did it while traveling less than 10% of the speed of light.
Cheers. ^_^
Thank you for translating!
OK, *finally* a video that actually does explain how photons can have momentum. (Fourth time's the charm; the first 3 videos I watched with titles promising to explain how/why photons have momentum were dumbed-down fluff that explained nothing.) Thank you for *not* being afraid to mention vector cross products, Maxwell's equations, Poynting vectors, etc. Thank you for *not* dumbing this down. Now I have a better understanding of what momentum is and why photons have momentum.
i love your energy
The example at 4:49 was pretty momentous for me. :-) If you wanted me to question everything I thought I knew about momentum, you've succeeded.
0:13 I'm getting SO ANGRY I'm gonna TEACH YOU SOMETHING!!!! >:O
Some of the confusion probably comes from the fact that we always write the equation as p=mv, implying that momentum is some emergent property of mass and velocity. Momentum is fundamental to an object, so it might be better written as v=p/m, as velocity can be described as the thing that changes when you apply momentum to an object with mass. For the special case of slow-moving objects with rest mass.
Man I really love your videos! Crystal clear explanations. I bought the book :)
Thanks! 🤓 I work really hard on these, so it's nice to hear they work.
@@ScienceAsylum Well what I like even more is that my 14 year old son understands this stuff and gets more clarity than some of the high school things he learns. Keep up the great on these complex areas!
yeah I like the verlet alg aproach, the difference in the positions of an abject in time results of a force, very usefull in the game industry
A lot of mass and little momentum, sounds like my wife...
nicely said. and questionclone's moment of apoplexy was hilarious.
Excellent. They should show this video at high school in physics. In the old days my physics teachers could not / did not explain momentum like so clear, … and later at university they either tell you that you had had the basics at school OR that anything you had heard at school was wrong and now you get the real thing, but seldom lecturers addresses the misconceptions (which was created earlier) in itself. It took me quite some focus and headaches to get rid of the wrong argument. Somehow if one is not immediately aware of a conflict between better and worse explanations, wrong arguments gain a life on their own and live a ghostly shadow existence (maybe because of wrong authorities, stress or inflexibility ?) until you force them to clash.
Off-screen clones
Liked before watching!!
lol thanks
this one messed with my head for a long time
Is it right then to think of momentum as a fundamental property separate from both mass and velocity?
Yes, in fact, that's a pretty _common_ thing to do... especially in quantum mechanics.
@@ScienceAsylum Thanks for the reply, I appreciate you a ton!
Mass called ... it feels unloved and unappreciated.
......that's understandable.
Venky Wank hahahahaha! ... I’m sure that would make it feel better!
Your videos are awesome, I just wanted to poynt (:D) out something:
2:31 - This works fine for objects with 0 mass because they are moving always by v=c, so gamma goes to infinity but, gamma*m*v stays finite and = E/c, so, no, it doesn't fail for light
LOL!!! You sold me with your opening statement: such passion.
4:54 'The fields are static.'
Were the metal plates statically charged or carrying a charge?
If you have a square with two magnets and two statically charged plates there's energy? Momentum, ie, moving energy?
The metal plates are statically charged, yes. The charge is not moving. You could say that energy flow (from the Poynting vector) is the "motion" for that momentum.... but now you're talking about a made-up thing (energy) rather than a physical thing (like matter).
Please tell me more about 1:51
What's the fundamental physics for friction? Both in Special/General Relativity & Quantum Mechanics. I must know
Hey, I have different one: 4:09 - If that's electromagnetic wave, why they're in phase? I've seen similar animation in other places as well and that confuses me A LOT. From what I've been told, peek of magnetic wave should be on the most change of electric wave. And the other way around. It should give electric and magnetic wave to be shifted by 90 degrees between each other, not in perfect sync. So why animation like this here?
So momentum is the integral of the sum of the forces on an object. Got it. But what exactly is a FORCE? I thought it was basically the application of energy, but I'm not sure that's right. This video really got me thinking about physics and calculus and now I really want precise definitions of force and power. I'm going to have to look into more, which is good because it'll give me head start for my physics class next semester.
I'm working on a video that will hopefully answer this exact question. It's a tough one.
@@ScienceAsylum link to the video?
I have the same exact question
I don't understand fundamentally the concepts of force and momentum, their definitions seem arbitrary to me
Hi bro you make awesome videos... Please I have been begging you to make a video explaining tachyonic particles
4:30 Wait, wait, wait. I get that momentum doesn't require mass, since it's more fundamentally related to energy and mass is just one type of energy. I can even get behind momentum not requiring velocity, since it's more about exchanging forces and it makes sense that fields can do that without having velocity per se, since velocity is a property of particles. But how can there be an exchange of forces if the fields aren't even _changing_ in any way? That doesn't make any sense to me. What am I missing?
You are missing the charged particle which trespass that area :)
Your reasoning is sound. Remember, _having_ momentum doesn't mean that forces are being exchanged. It just means that they _could_ be exchanged. I can't think of an EM scenario where momentum is conserved but the field doesn't change.
@@ScienceAsylum Oh, so you mean like if a single object is moving, it has momentum even before it hits anything?
@@Lucky10279 Exactly.
Important question
What force pushes light particles from its source to its surroundings? Like the sun has light but what makes that light travel to us on earth?
*"What force pushes light particles from its source to its surroundings?"*
Steady velocity is the natural state of motion. No force is necessary to move at a steady velocity. You only need forces to speed up, slow down, or change direction.
Curvature of space-time continuum 😜😜😜😜😜😜😜
Hi Nick 😊, good day... Hope am not too late in asking this question: can we extract energy from an object that is changing reference frames??
I'll have to add "burning my old physics textbooks" to my to-do list.
4:24 how momentum is related to energy for light? Have made any video for that? if yes can you please link it down to me replying this comment ?
@The Science Asylum
I was thinking about metals recently like why they produce "metallic" sound when hit with something...
Other properties of metal can be explained by electron sea theory like shiny nature of metal, malleability, electricity and heat conduction etc. But I couldn't find any good explanation for why they produce "metallic" sound..
If you could explain it, it would be tremendously helpful..
I am no expert at this, but hitting something produces a short peak of force. To construct such a peak from harmonic frequencies means that there is a large spectrum of them. And some of those frequencies will match the resonant frequency of the metal object, which means it will resonate for a while until it dissipates all the energy to air, and produce a distinguished fading sound. That is how I explain it at least...
Great explanation ... the best i've heard ... You are smart ... Because it takes a smart person to describe the matter so that anyone can understand.
Your chanel is amazing! I learn a lot and as much I learn more questions I have. It is great!
Another excellent video, really enjoy your channel. But I’m surprised you did not comment about the vector nature of momentum. How each component of momentum (x,y,z) is independently conserved
How are orbits of stellar objects continuous collisions? What's the difference between momentum and inertia? Do we get better solar sails from mirrors or vantablack? This video raises more questions than it answers! Which I love. But also hate. I hope you have a lot of follow up videos planned.
The momentum of those orbiting objects is continuously changing. They are continuously exchanging momentum with each other. That exchange in momentum is related to the force of gravity between them.
Great Video like always👍🏻
Can you explain a Sonic Boom and what actually happens? Would be interesting.
Can you do a video about electric potential and electrostatic?
I've been trying to figure out how to make that exact topic interesting.
Today YT Recommended your Channell Awseme stuff Keep It up...
Glad you found it!
at 1:38 the pushing and pulling phenomenon can be explained by lenzs law?......since it is involved the electromagnetic force.
Sir try to reply pls...
@Dr Deuteron how
Can you do a video on how wheels work? It might sound like a trivial question, but I still have questions like “Why don’t wheels speed up indefinitely if friction is in the direction of movement?”. Please don’t refrain from including details.
Another great, informative, well explained video. Thanks !
Please consider answering this question: According to special relativity, if an object with mass reaches the speed of light, time stops for it. Because light has no mass, does special relativity not apply to it? Light takes time to travel from Sun to Earth. What is your opinion on that?
These are my thoughts on that: th-cam.com/video/a9T26ItpcDA/w-d-xo.html
I really really love these videos.
According to @5:20 (Newton´s second law), wouldn`t it be more useful to declare the momentum as a SI-base unit?
For the sake of the models? Yes. However, theoretical physicists are not the ones deciding what the base units are. Experimental scientists do that and they have different priorities. The base units are set up to be the things we imagine ourselves measuring directly in experiments. No one measures momentum directly.
So, maybe I’m off base here, but could you propel a space ship with a rail gun? Of course firing a projectile would have an opposite force on the ship, but what if you fired the rail gun with no projectile? Would that still propel the ship in the opposite direction? It creates a magnetic field, and as it moves toward the opposite end, would it want to stand still and move the ship instead? Your discussion spawned this idea in my head.
Well, whether or not a rail gun would even work without a projectile in it would depend on the design. Some designs require the projectile to close the circuit. Assuming, that's _not_ the case, there's only one way that would work to push a ship forward. You'd have to make sure the EM field changes the rail gun was creating released momentum in a particular direction. If you manage that, what you've create is light (maybe not visible light, but light nonetheless). That light behaves just like the projectile would have and momentum must be conserved. Whether or not you get a _noticeable_ thrust will depend on how much light you generate (spoiler alert: it needs to be _a lot!_ ).
The Science Asylum yes that makes a lot of sense. I suppose you’d wind up with electrical plasma drive, which is already being tested. It doesn’t have much thrust, but can run for a long time, which is its advantage. I’m thinking more of a ship that generates a magnetic field around it, starting at the front, the field moves to the rear, over and over. Would the magnetic field want to stand still, and push the ship forward inside the field? Or would it have no effect? Kind of like having a fan on a boat blowing into the sails, the opposite effects cancel each other out. As far as a rail gun, if you shot actual projectiles it would push the ship, but you’d eventually run out of projectiles. Thank you for the reply! Love the channel, always thought provoking!
Just generating a magnetic field (single-handedly) would have zero effect on the motion of the ship. If it were strong enough to deflect solar wind, it could pick up momentum from those particles gradually over time... but I imagine the power requirements for a field that strong would be absurd.
The Science Asylum thank you for the response! And yes I see your point. I’m thinking of a Mag Lev train, but the magnets have something to push against, and you can’t push against space, apparently. You’d need anti-gravity to push you through space, which is very different from a magnetic field. And, hasn’t been invented yet, so there’s that. Love the channel!
I love your videos! However, how does light exert a force if it's only a wave? Or particle? I'm not really sure I think both but I know for sure it's just energy so how can that physically push stuff?
Hello, The Science Asylum! Could you make a video on color? Such as how some objects are green because of reflecting green light? Thanks! :D
First I need to understand the physics thought now ,then understand it’s misconceptions
Great guy ,u rock man
Thank you,
I always thought than the reason light has momentum was because of the mass/energy equivalence & the lorentz factor approaching infinity.
Thanks again for the videos! I've got 2 questions that have been bugging me:
1) Is there an upper limit for sound frequecy in Earth's atmosphere? Google hasn't helped me.
2) why does the observable universe look so uniform, if light has taken different amounts of time to get to us the further out we look?
1) yes. we haven't reached it but it is estimated to be between 3-5GHz. The problem is the larger waves only go very very short distances before being absorbed. Remember a sonic boom, is typically below 100hertz. and the limit is estimated at 3000-5000hertz.
2) our eyeballs are both right next to eachother for us to gauge distance. Those stars you see in the sky actually aren't as uniform as you think; the difference in the brightness between stars is used to tell how far they are; it is more complicated than that but hope I gave an idea to think on.