The average person would benefit immensely from this channel. They just don't teach enough physics in schools, so most people walk around quite ignorant of basic concepts.
I'm an average person and I try to understand what my pea brain allows me to. I find all things about the universe quite interesting... I am not smart enough to understand even a small percentage but I do try
I have grown to greatly value your programs. You presentation style and timing are very accessible and in fact, make your lessons a pleasure to watch. Thanks for your hard work, and for making some often knotty subject matter so much more comprehensible.
I don't think we know. But I think his videos on Fermilab will give more advanced ideas at least than this video. edit:I added my speculation in another comment
Let's don't see it as speed of light, or even as a limit, it isn't a limit, it is just a speed that we humans have calculated it to be relative to our understanding. But what it really is simple - The more you move in space, the less you move in time, the more mass you have the less you move in space with the same energy, and light don't have any mass, so it doesn't move through time but is moving through space infinitely, you see, relative to a particle of light, it hasn't aged a day since the big bang. Think of it like, you can move through space and time, but only when the sum of it is 1. So maybe you can move through space 0.4 and through time 0.6 but never more than that, the Universe will limit you from doing so, if you reach the speed of light time slows down so you only move so much, so that casaulty is maintained.
Technically, he didn't really answer the question of WHY the speed of light is the limit. I was hoping to see the reasonning of Einstein when he came to that conclusion. Great video though!
@@colleendougherty4475do the predictions of: Time dilation Length contraction Antimatter Black holes Non static universe Frame dragging Shapiro delay Convince you?
Man, I just love Don Lincoln. Fermilab has been a great source of knowledge on physics for me and I have always enjoyed his intellect and dry sense of humor that occasionally comes out.
UFO= not exactly name,g because they can out gravity, right call space ship travel speed of light, the pilot is human, allein or et,,,,,100% handsome and pretty ,100% kindly
I imagine the value for the speed of light was rounded. There are probably other digits in the speed of light. But he said "exactly" at least twice. Also is he a PHD physicist?
Fundamental constant...we don't know for many...but faster you move thru space slower time is going for you (its proven, with observations everywhere) and at 100% speed of light time would stop for you, literally. Yes ik what ou have in mind even if you know relativity but it seems its physical constant like many others and we simoly don't kbow why, how it just works-like quantum mechanics, we don't know why and how we just know it works and all technology since 50s is at one point based in QM
The major difference between the baseball thrower and lightemission is, that while the speeds of the thrower adds to the speed of the ball, light is just set free to travel at the speed it chooses given the medium - it cannot be affected (bothered) by the speed of its source.
The title is misleading. This video does not say why the speed of light is the speed limit, only that we observe the speed of light to be the same everywhere.
It’s because mass grows and becomes infinite at the speed of light. So if you shot a BB gun at the Earth at the speed of light it would destroy Earth according to Einstein and that kid from “A Christmas Story” who stuck his tongue to the flag pole. I think they both would agree. Hopefully without swearing. Thanks 🙏🏻 I hope this helped you out, but I thought it did say why, so I don’t know 🤷♀️ If you have any more questions I am ready. Thanks 🙏🏻
The speed of light is completely a function of the medium it traversed. Specifically as Maxwell showed in 1860 = 1/(sqrtf(u0)**2 * sqrtf (e0)**2). With u0 magnetic permeability and e0 electrical permittivity. These last two may vary depending upon medium eg free space supports faster speed than water.
@@BlackPDigitalMedia No the "realm" is our universe's free space and thus the speed of light is constant there. Quantum objects in our universe cannot defeat this restriction. Note again that different "media" eg water will transmit light slower as they have different u0 and e0.
@@spiralsun1 In EM radiation what is moving through space? If it is the photon, it have the energy h when it is emitted by an electron. Then the mass of a photon is h/c^2. If the photon is moving at the speed c then too it's mass have to increase towaards infinity. But it is not happening. It remains constant. Why?
"Why the Speed of Light is the Speed Limit" - but the video showed what the speed of light is, and how it is measured, but not why it is what it is, and not why it is the speed limit.
Exactly. I suppose nobody can answer the question posited by the title. Unclear why it is titled wrong given how smart the content seems to be. Clickbait, I suppose?
Though I don’t implicitly doubt the conclusion of the final experiment, I’m having trouble understanding why it proves that the photon is moving at the speed of light with respect to the electron. It only seems to prove that it moves at the speed of light respective to the stationary detector, irrespective of the speed of the emitter. I don’t see how that experiment is demonstrating the perspective of the emitting electron at all.
Go back to the pitcher on a train analogy. The pitcher throws the ball at 100mph + the train moving at 100mph = 200mph to the observer. But only 100mps from the pitcher's point of reference. Got it? Ok, so the electron moving at c + photon emitted at c should = 2xc from our perspective. And from the electron's perspective the photon should fly away at c, just like the pitchers ball moves away at 100mph on the train. But c is constant in both frames, unlike the baseball, and in both frames the photon and electron move at the same speed which is c.
I would say that it is not a demonstration that different observers see light at a constant c. It is just demonstrating that any light generated from a source will be seen by us as the observer to travel at c whether the source of the light is travelling either towards us or away from us at c. c is dependant upon time. If the emitting source of the light is travelling at nearly the speed of light then time will be slowed and therefore it will still see the photon travelling at c.
Thank you for this quite excellent vid on the "C" constant along with its bonus, strong History of Science flavor! My subscription was instant, if not as fast...
With regard to your gamma ray burst you mentioned, you stated that the photons arrived within a few seconds of each other. Now there are no particles in a wave but that gamma ray did induce excitment intophotons that you were able to register in your equipment as you stated. But at no time did thoes photons originate from the place that gamma radiation started traveling from. Just like the ocean wave example you showed earlier in this video. the particle or boat does not move with the wave other than up and down with the waves amplitude. Gamma rays are no different than that wave in the ocean and the particles we see are not visiable until that ray strikes something like a particle of mater that then sende that energy in all directions for us to see it as it stricks our retina in the eye and excits particles responsiable for our sight. The analogy I use is the wave moving through the ocean with no particles in it until that wave stricks the beach and imparts the wave energy into all the sand particles it strikes on the beach. But the energy wave it self has no particles.
SR does not claim a speed limit for C - it simply says things can not accelerate through and beyond C - not that things are not already moving [unaccelerated] at beyond C - how come so many folks do not know this?
Except Einstein’s theory never says you can’t go faster than the Speed of light. Einstein never even said it that is a construct created by all the rest of you.
This video was AWESOME. ❤ One of the few to actually talk about the huge leap in thought that light has a finite speed. We so take that for granted. Ole Romer actually constructed a telescope with calibration to do the measurements then squinted through a telescope carefully night after night and figured that out. Just mind-blowingly amazing! I loved how clear and carefully the topics were covered thanks!!! ❤
The speed of light being the same for all observers is telling us something deep and fundamental about the universe. Have often thought the same thing but this is the first time I've ever heard it said in such a direct manner. Thank you!
@Matthew Philip Well the short answer is I don't know, yet. Another thing that makes me wonder is photos traveling at the speed of light apparently do not experience time. If I figure it out I'll let you know or you'll hear about it when I pick up my Nobel prize. 🤣
Loved this Thankyou. A couple of things, all the standard model particles that "Occlude" need to be the same size (12 Planque ish). The superposed nature of photon weight versus frequency... The "Particle" and the QM field wave are always "there" it's the spacial collapse and expansion for the raw weight that is frequency. So does the entire "magnetic" aperture of the photon disappear and reappear (Polarity question) ? Lensing is likely another double aperture addition, but if symmetrical flow energy is the vector driver, the "longest" distortion and therefore the lowest pressure is on the wrong side, but the planet side compression is 12 Planque higher than the outside so back to a kissing hawking reaction over time spinning the lowest flow density aperture length to the outside, resetting after frequency cycle completion ? 😁 Love your work DrDon. Thank you again Bernhard
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
Thanks for the video, some good explanations, and there is a lot of them out there. I'm seeing this line of reasoning over and over again, and every time I'm left puzzled. It seems to me we have two different things here. First, since we don't really have a medium for light, i.e.the very space itself is the medium, and if we suppose it's fixed (although GTR says it's not, but lets leave that aside here), then it's no surprise that it can't be pushed by anything. Because it's not really pushed (or thrown or whatever), it is more generated. That very fact is enough for us to say that the photon could not travel faster than the speed at which the space itself could spread the electromagnetic disturbance (that is very similar to Maxwell's derivation from two different permeabilities). So that part is pretty obvious. The second part is what puzzles me, and that is hidden inside the following sentence: "..the electron sees photon traveling at the speed of light...". First of all, how we know this? I'd say that is not something that could be deduced from any of these experiments. I know it's one of the conjectures, but could you please say what exactly proves that part? And I think it is crucial. As I see this, that part is what makes the (Einsteinian) relativity so "weird" - it gives rise to time and length dilatation, effectively the usage of Lorentz's transformations.
The geometry of the gravitational field requires that the electron measures the speed of light to be c. There is no way to render a different result consistent with the results we obtain in the lab.
@@kylelochlann5053 ok, but I don't see that in the line of reasoning in this video. I'm just saying that from presented reasoning and experiments we cannot say that the source of light, traveling in the same direction as that light, perceive it's velocity as c. I would really like to see explanation on that. The fact that emittion of light is not the same as throwing a ball from the train is far more obvious.
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
@@darkososyt Correct, the video presumes a basic understanding of relativity, which isn't obvious to anyone who has not studied it sufficiently. The constancy of the speed of light is owed to the local structure of the gravitational field and originally taken as a postulate by Einstein on the assumption that the electromagnetic equations of Maxwell are correct. Nowadays the local constancy of the speed of light is taken as a consequence of the spacetime interval being null for light, i.e. ds=0.
@@kylelochlann5053 that's very interesting... For some reason I'm trying to understand this, and the more I watch videos on the subject the more questions I have :) Anyway, as much as appreciate people that make these kind of videos, seems to me that there's always something missing in line of reasoning. And often there is a mix of things like "light between mirrors on a train" and some math equation which already have many other thing hidden in it. I'm a mathematician by education, so to me, if we assume something and then make equations that are the consequence of those assumptions, even if the equations proves right, that doesn't mean that our assumptions are true. Logically, from false assumptions you can deduce right conclusions. So I'm trying to learn what exactly are facts and what are assumptions, or consequences of assumptions. I mean, if we knew everything, there would be no need to question anything...
I had a great time listening to you. I unfortunately didn't learn physics,nor astronomy, but am very interested by it. So I rad and watch on Internet everything that is related to it.
Love your videos....reminds me of the joy of calculating particles in a box at U of Chicago undergrad, but that gamma ray burst example you gave was simply mind-altering / bending/expanding! Thank you, Doc, for your understated-profundity!! ;)
Once we connect with all energies and anti energies in this and other universes and dimensions, we will be able to travel at the speed of thought. Then, we can be everywhere at the same time. I'd have 100 of myself in every existence. Always learning and helping those who want it.
From my probably messed up understanding, it must be due to time dilation at the speed of light from the electron perspective vs the outsider perspective with no time dilation.v
Why? They aren't using any energy to travel. Surely they are set in motion when they are released from matter, then maintain that motion until they collide with something.
Is there a theoretical consequence to traveling FTL? What would happen to matter if it were to exceed the speed of light (e.g., particle breakdown, going plaid, etc.)?
Nothing would happen and time (and all else) would be normal for you. You would be moving traveling a negative length and this doesn't make physical sense, and you'd be able to send messages to yourself about events that haven't happened yet. So, it's not so much a problem as that it is meaningless.
Once you go faster than light, there are frames where you are teleporting instantly (to outside observers), and more in which you are going backwards in time. Just say no.
Also, the rotating mirror type experiments to measure the speed of light are even easier (require less than 500ft, tho bigger distances is indeed better) to do than the ones mentioned in the video and get between 10% and 1% error depending on how careful you are in setup.
If we were to take as gospal that the speed of light is the fastest speed possible then does this apply only when it comes to normal space? What happens when space bends, stretches or condensed? Of course all things are relative. Since speed has a time component influenced by these effects, does that then effect the speed that light travels? There are times when it seems the fabric of space time can cheat the speed limit by being full of holes that allows energy to seemingly exceed the speed limit by taking short cuts across the universe.
The Lorentz factor really represents projections back and forth between the two frames of reference, if you interpret it as a cosine (!) instead. The apparent "length contraction" and "time dilation" arise from the 2D length and time "vectors" ( both complex variables ) each pointing in different directions in their respective complex planes between the two frames of reference , the more the faster an object moves relatively to the observer"s frame of reference. Gamma^(-1) = sqrt( 1 - v^2/c^2 ) So they don't shrink (contract) or expand (dilate) at all - it's their projections (!!!) - or their "presence" if you like ! - in the frame of reference of the observer that shrink or expands. ( and the other way around as well of course ). As v goes towards c, gamma will decrease to 0 - in which case the length dimension of the object along the axis of motion is entirely "out of" ( not present in ) the length dimension of the observer. Think of a "unit" circle in the complex plane with radius c and v along the imaginary axis (!)
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
@@jamesh9174 Well, there is - but then we would measure different values for the speed of light from different frames of reference - and we don't (!!!), which is very counter intuitive and weird. So something else "has to give" so to speak for that to be true - namely the concept of a universal time and fixed spatial dimensions. They (now) depend on the frames of reference of the observers. From the frame of reference of the photon it reaches our eyes INSTANTANEOUSLY from the light source, since no time is passing for it, as the spatial dimension along its direction of "travel" is contracted to zero length ( v = c, in the Lorentz factors ) - or its "presence" ( the projection of its length dimension ) is reduced to zero, as I prefer to see it 😉
@@Bjowolf2 I like this "something has to give"! This is exactly how I have thought about these matters. Nothing shrinks or expands but the measurement of these parameters. It is not necessary to think of a an object actually shrinking in the direction of motion, only that the measurement of such changes with relative velocity. Of course, my view here raises the question of whatever "actually" means in these contexts.
What if a car could travel at the speed of light. Would the light from the headlights of the car be traveling at twice the speed of light? I would guess yes, but probably not correct. 😊 Also, if a car was traveling 60 MPH would the light from the headlights of the car be traveling the speed of light plus 60 MPH? I would think so, but that probably is not correct either. 😊 Physics is so much fun. 🙃
Very good video, though I think it did not answer to the question in the title. I saw another video about this topic on PBS SpaceTime where they tried to explain this question. If I got that correctly (sorry, I'm not a scientist just a poor electrical engineer) the takeaway of that video was that (and they were referring to some articles there) if we make some basic assumptions about the universe (and I'm talking about real basic stuff here, like the cause must always comes first and the effect is only later). So based on these assumptions it can be derived that there must be a cosmic speed limit with which NOTHING can travel faster. This speed limit is the speed of causality. And it happens to be that the light has this speed (and as a matter of fact because its stationary mass is zero it cannot go slower - I mean, in vacuum.). Perhaps some video about this topic on this channel would be useful.
I'd be really interested in a quantitative analysis of the risk associated with mercury in the Michelson-Morley experiment. I suspect that it would accord more with Michelson and Morley, rather than the modern practices. I suspect that Mercury is dangerous at elevated temperatures or when complexed in bio-chemically active compounds, but that room temperature mercury is far safer than smoking and driving cars, let alone rock climbing or hang gliders. Probably safer than living in Colorado.
My question is this: if photons have no mass then why would they be subject to the universal speed limit? As i understand it, the reason you cant go faster is that you gain an almost infinite amount of mass which would take an almost infinite amount of energy to move you at that speed. If photons have no mass then what would prevent them from going faster? Obviously it wouldn't be energy constraints. What did Einstein have to say about that?
It still does have energy constraints, but instead of mass, a photon gets its energy from momentum, its wave travel. They actually follow a different version of the formula, E=pc, rather than the more famous one, with p being momentum.
PLEASE RESPONSE IF YOU ARE GOOD IN PHYSICS At 23:00 it is mentioned as a conclusion that the photon is travelling at the speed of light to both, me and to the electron. But where does the conclusion come from that it travelled at the speed of light to the electron? Theres no indication for this, neither in Michelson-Morley experiment nor in the observations of the particle accelerators. Imagine the electron flying above a still lake with the speed of light, dipping into the lake. The wave travels at the speed of light right beside the electron above. I don't get where the conclusion comes from that the wave travels at the speed of light away from the electron.
It is no the speed of light that is the limit, but the speed of causality that is the limit. The speed of light can vary depending on the material properties of the medium it is passing through.
This guy is a good teacher. Altho beyond the scope, my understanding is that measuring the speed of light in one direction is not achievable. It’s measured by round trip b/c of a problem with keeping two separate clocks perfectly synchronized.
In the experiment with the electron and the photon, both traveling the same, it has nothing to do with the “observer.” It has to do with the fact that the photon has no mass, therefore there’s no inertia, or centripetal force as pertaining to gravity. You can’t sling, or throw something that has no mass. Nothing to do with “the observers.”
So I've always wondered. If you were traveling just 1 mph below the speed of light , and you take a baseball and bat that are traveling with you thru space at 1 mph below the speed of light. What would happen if you hit that baseball with the bat in the direction you are moving? Because from your vantage point you and the ball would be at rest but physically you and the ball are both moving thru space at just below the speed of light. So would the ball exceed the speed of light or would it just not move and shatter the baseball bat?
Nice explanation. My only question: This experiment to measure the speed of light with 2 electronic timers, is it not too simplistic? (1) How far need they be placed apart knowing that the c = 300 000 km/s? (2) How do we synchronize the 2 clocks at the start?
Maxwell method of deriving the wave equation is in correct. Electromagnetic fields are generated by sources and the sources can not be set to zero as Maxwell did. This is because Gauss"s law and Amperes law have source terms. When the sources are included, this yields a inhomogeneous PDE wave equation, where the wave equation is set equal to a source term. Solving this PDE is difficult but has been solved by many researchers, yielding a nonlinear phase shift vs distance from the source dispersion curve. Applying well known operators to the dispersion curve, inversely proportional to the slope of the curve, shows that the phase speed and group speed are both instantaneous in the nearfield and reduces to about speed c in the farfield starting at about 1 wavelength from the source. From there the speed asymptotically approaches c but never becomes exactly c even at astronomical distance from the source. So the speed of light is nowhere a constant. It is just a good approximation in the farfield.
Thanks for the detailed explanation of the Michelson - Morley experiment. And for mentioning that it was conducted in my home time of Cleveland. Ohio at The Case School of Applied Sciences now Case Western Reserve University. I contend, whenever and wherever the opportunity arises, that, in a very real sense, my hometown is the birthplace of Einstein's theory of relativity.
There is a mismatch between the title of the video and the contents. There is nothing in the video to describe why the speed of light is the ultimate speed.
Yes! I wondered the same. It is my understanding, that we can only measure the "two-way" speed of light. This video seems to suggest different, that the "one-way" speed of light can also be measured. I believe that is in error. Great observation. 👍
"The speed of light, being the same for all frequencies and wavelengths, and the same for all observers says something very deep and fundamental about the universe. Mind you we don't know exactly what it is, but it is clearly telling us something." That is a profound and essential observation. I do know exactly what it is telling us. It is that the speed of light is a boundary phenomenon between two different levels or regions or planes of the universe. On our side of the speed of light, everything travels at or below that speed. On the other side of that speed, everything travels faster, up to the light of that region, which is another boundary. There are seven such boundaries, all held in the overall gravitation, which may be one of the things that can leak through these boundaries, and my guess is that may account for dark energy and dark matter.
What it tells us is that frequency and wavelength are not properties of light. They are consequences of the frame in which the light is observed. It really is that simple.
19:00 How does that disprove the aether? Doesnt it just show that the aether is uniform in all directions? Why would we have assumed that the aether would produce a different speed of light from different directions in the first place? Havent we just renamed the aether to "spacetime" in the 21st century?
Don Lincoln is wrong. The MM null result only shows that the ether is unnecessary. All that is needed is the existence of the gravitational field, which is not an aether, which is a magical entity that lives on top of spacetime.
@@kylelochlann5053 Every McGuffin in physics is just "magic" rebranded. Dark matter, dark energy... unproven, unwitnessed. Its a "thing", an entity, that stands in for ignorance. And they contradict. We came up with dark matter because we see saw too much gravity in the universe for the matter, and then we came up with dark energy because we saw too little gravity in the universe for the matter. Instead of questioning the gospel of Newton and Einstein, we merely took a dump on Occum instead. The amount of blind faith that the current cosmological community embraces is astonishing to me. Take 100 years of questionably-accurate galactic motion observations, and extrapolate it into the past thousands of orders of magnitudes beyond what any statistician would ever allow if accuracy were even a concern, and call the result "big bang". Lets also ignore all the hard evidence taken from observation that contracts the basic tools we use such as red shift (NGC 7603), the 10 B yo star, and other observations that challenge the scientism narrative. Then brand it as a theory when in fact its barely a hypothesis, just to give it a little extra pop culture credibility. Dont like spontaneous generation of life? Too religious for you? Supplant it with evolution, and then "invent" a "whole new idea no ones ever thought of before" that we call abiogenesis instead, to explain the origins of life. Hush, its the same thing as spontaneous generation. Quit calling concepts "magic" to distance yourself pseudointellectually from them, when youre just going to replace them with other magical things.
If I learn, in a relative and practical way that makes sense, what a light year is, watching this video will be the best 30 minutes use of my time. Look out universe and the Big Bang Theory 🎆 because I’m coming for you now.
Seeing how we've left reflectors on the moon during the Apollo missions. When we shine lasers at them do we, like a sniper trying to hit a moving target, have to lead the shot?
Don Lincoln should NEVER talk about relativity. Every video contains misinformation. In this one we have electrons moving at the speed of light. Seriously, wtf? He never gets to why there is a speed limit because he doesn't have the slightest idea how relativity works.
Just one question from layman: While explaining the particle accelerator experiment at t23 you showed that the electron and the photon both reached the second detector at the same time. This showed that the speed of the photon was still c and not 2c. But how did you know that the electron observed the speed of that photon as also c instead of 0? To prove that the speed of light is same for all observers, you have to show both, right? That the stationary observer as well as the moving observer both observe the speed of the photon to be c?
The constancy of the local speed of light for all inertial observers is a consequence of the causal structure of the gravitational field and not something that can be covered in this video.
@@hanumantd That's right, it doesn't. and I disliked it for the clickbait title. Based on his other videos, I'm confident Don Lincoln never took a course in relativity and doesn't know the answer. EDIT: Lincoln would have used relativity in his course work and professionally. In grad school the high energy group (the particle physics kids) could often calculate things in relativity quicker than we could, but they had no idea why anything was the way it was (and often had hilarious explanations of what they thought the physics was about).
Physicists had some interesting bloopers in history. One of them is naming the constant "c" the speed of light. Actually c = 1/√(ε0μ0) where ε0 is electrical permittivity of free space and μ0 is magnetic permeability of free space. Hence c is nothing but maximum speed at which vacuum allows electromagnetic wave / pulse to travel. Mind it, there's nothing called perfect vacuum in the universe. The fact that light is an electromagnetic wave pulse (which behaves like discrete particles in some situations) is a special case of electromagnetic waveforms. Other cases like radio waves, x-ray etc. function in similar manner.
Speed of light has to do with a nature of space. We know that electric permittivity (epsilon naught) of vacuum or free space and magnetic permeability (mu naught) of free space are constant everywhere, that's why speed of light in vacuum is the same everywhere and independent of frame of reference. It is simply observed that way. It is one of the fundamental constants. The constancy of speed of light is one of two conjecture of the special theory of relativity.
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
THE PARADOX THAT DISPROVES SPECIAL RELATIVITY: There is a triangle of lights which we will call A, B, and C. They flash simultaneously in the frame of reference that is at rest relative to these lights. There is someone moving at a high rate of speed from B to A. There is someone else moving at a high rate of speed from C to B. There is someone else moving at a high rate of speed from A to C. So A flashes first and then B flashes and then C flashes and then A flashes again. How can A flash twice? When A flashes has B already flashed or not yet flashed? or B flashes first and then C flashes and then A flashes and then B flashes again. How can B flash twice? When B flashes has C already flashed or not yet flashed? or C flashes first and then A flashes and then B flashes and then C flashes again. How can C flash twice? When C flashes has A already flashed or not yet flashed?
You start up saying that they all flash simultaneously. Then each traveler will only see one flash from each point but at different times. The travelers speed only matter to make it possible to see any difference in when the light flashes arrive and possibly also the color of the flashes.
You seem to be describing what different observers see and then asking how they can see different things. Relativity accepts that events that look simultaneous to one observer need not look simultaneous to another. Also, you could do this same experiment with Newtonian physics, or so it with sound. Or BBs.
@@vesuvandoppelganger You started up by saying that they flash simultaneously and by that I understand that if seen from a point with equal distance to all three points they would be seen as flashing simultaneously. Any person at anywhere else around will see the flashes when they come to them. Time = c/distance. None of them will see more than one flash from each point. It is my belief that if an electromagnetic impulse (in this case photons) is emitted from a point in the universe this point is fixed meaning it doesn't move even though it is emitted from a moving object. Any movement can be noticed in the frequency of the signal but not the speed. An example it speed radar. I believe that you can't tell any difference if you check the speed of a house if tested from a moving car or if you are standing at the house and testing the speed of the car. Another example is the redshift from far away stars that supposedly move away from us. Some people say that electromagnetic waves (including light) are moving in some quantum field. My question is: Isn't that just another name for the eather that has been disproved to exist? I believe electromagnetic pulses (photons) are energy pulses or quanta's that can exist on their own just like a small space ship. They are pulsating giving them the appearances of waves. This in my opinion would explain the double slid performance. That free electrons supposedly also show up as both particles and waves in a double slid setup would indicate that they are also wavy particles. They are much bigger and have gained mass and as such can be accelerated but also move at much lower speed.
@dhouse witness testimony is the least credible form of evidence. If you knew anything about science you would know that. I have yet to see a single peer reviewed paper outlining how FTL travel is possible, and includes demonstrations. Nor are there any papers with any evidence of extraterrestrial life. So if all you have is hearsay, you have nothing.
@@paulcarfantan6688 neither have been demonstrated to travel faster than the speed of light. I don't think tachyons are even real, right? I'm pretty sure they are still entirely theoretical.
ALL matter in the universe is at all times instantaneously communicating to all other matter in the universe, no matter how many millions or billions of light years away, on the quantum level, via gravity, whatever gravity is. That communication is faster than the speed of light.
This was a very helpful and informative video. One thing was confusing to me and it may be that my understanding, prior to watching this video, was just wrong. What I have understood the statement "the speed of light is the same for all observers" to mean is that speed is the same for each respective frame of reference. Meaning, if I'm traveling on a shuttle in the direction of a light beam at 1/2 the speed of light, that beam of light is traveling away from me at the speed of light. But, to a stationary person, that beam of light is still only traveling at the speed of light. I thought that was how time dilation occurred. After watching the final experiment here, though, I have more questions. Having a beam of light emit a photon and measuring that speed from a single point of reference does not feel the same as measuring one (or even two) beams of light from different reference points.
That is for Transverse electromagnetic waves. And we will have to go back to the aether. I think it was Oliver Heaviside who simplified JC Maxwells 20 equations in the 4 know today as maxwells equations.
All propagating modes are transverse, but it works for near field effects too, it’s just that studying those fields only adds difficulties, not elucidation
On the front of an electromagnetic wave an energy front travels also and it has its equivalent relativistic mass; hence it curves space. That is, it generates gravitational waves that propagate at the speed of light, the same speed at which the EM wave that curves space travels. But the fabric of the universe has inertia that opposes its curvature, it is an opposition to its displacement that faces light and that determines the speed of light (or gravitational wave).
Excellent. I am looking forward to your video on the speed of gravitational waves. Since they are not an electromagnetic phenomenon, there is no obvious reason why they should also travel at c.
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
In the electron/photon experiment, what if you move the detector towards the photon? Will you detect the photon sooner than a stationary detector does?
Speaking as a Flatusist, all that M&M at Case and the acceelerated electron vs photon proved is if there were an aether, it doesn't pass wind. How about fill the vacuum of space with neutrinos that then function as dark matter and energy as well as being the medium that allows all starlight to travel everywhere, captured wherever a mirror or retina reside. No wind, light only becomes particulate when it interacts with something, the neutrinos acting as nothing, or existing materially in a different dimension. But I'm guessing, or gassing.
The average person would benefit immensely from this channel. They just don't teach enough physics in schools, so most people walk around quite ignorant of basic concepts.
I'm an average person and I try to understand what my pea brain allows me to. I find all things about the universe quite interesting... I am not smart enough to understand even a small percentage but I do try
Some folks are quite content being ignorant, unfortunately.
I have grown to greatly value your programs. You presentation style and timing are very accessible and in fact, make your lessons a pleasure to watch. Thanks for your hard work, and for making some often knotty subject matter so much more comprehensible.
So WHY IS SPEED OF LIGHT the speed limit then?? I hate it when videos don’t answer the very question they pose in their own title.
I don't think we know.
But I think his videos on Fermilab will give more advanced ideas at least than this video.
edit:I added my speculation in another comment
Let's don't see it as speed of light, or even as a limit, it isn't a limit, it is just a speed that we humans have calculated it to be relative to our understanding.
But what it really is simple - The more you move in space, the less you move in time, the more mass you have the less you move in space with the same energy, and light don't have any mass, so it doesn't move through time but is moving through space infinitely, you see, relative to a particle of light, it hasn't aged a day since the big bang.
Think of it like, you can move through space and time, but only when the sum of it is 1. So maybe you can move through space 0.4 and through time 0.6 but never more than that, the Universe will limit you from doing so, if you reach the speed of light time slows down so you only move so much, so that casaulty is maintained.
@@crewrangergaming9582
I understand all that. My complaint is the clickbait nature of the title. It didn’t even address it’s own question.
I don't think he knows why.
@@joebloggs396 Of course we know, though I'm confident Don Lincoln doesn't know.
Technically, he didn't really answer the question of WHY the speed of light is the limit. I was hoping to see the reasonning of Einstein when he came to that conclusion. Great video though!
fancy words never convinced me .
@@colleendougherty4475do the predictions of:
Time dilation
Length contraction
Antimatter
Black holes
Non static universe
Frame dragging
Shapiro delay
Convince you?
@@DrDeuteron No.
Man, I just love Don Lincoln. Fermilab has been a great source of knowledge on physics for me and I have always enjoyed his intellect and dry sense of humor that occasionally comes out.
UFO= not exactly name,g because they can out gravity, right call space ship travel speed of light, the pilot is human, allein or et,,,,,100% handsome and pretty ,100% kindly
I imagine the value for the speed of light was rounded. There are probably other digits in the speed of light. But he said "exactly" at least twice.
Also is he a PHD physicist?
Great video...but doesn't answer the question in the title of why the speed of light is the limit. Perhaps change the title?
Fundamental constant...we don't know for many...but faster you move thru space slower time is going for you (its proven, with observations everywhere) and at 100% speed of light time would stop for you, literally. Yes ik what ou have in mind even if you know relativity but it seems its physical constant like many others and we simoly don't kbow why, how it just works-like quantum mechanics, we don't know why and how we just know it works and all technology since 50s is at one point based in QM
@@gasperstarina9837 why does time slow down ?
@@Jazz16-we1qc Get real we are talking about science not fairy tales.
@@stefan24georgievbecause the natural symmetry of spacetime preserves time squared minus distance squared. All observers measure the same value.
@@DrDeuteron you are giving me an explanation of the of the equation. I am asking what causes the equation.
2:46 I love on a video about how and why nothing can exceede the speed of light, he proceeds to round it up.
The major difference between the baseball thrower and lightemission is, that while the speeds of the thrower adds to the speed of the ball, light is just set free to travel at the speed it chooses given the medium - it cannot be affected (bothered) by the speed of its source.
That's great explanation, for a six year old.
Good explanation. It doesn't seem to prove the speed of light is constant for all observers.
What medium? There is no medium.
The title is misleading. This video does not say why the speed of light is the speed limit, only that we observe the speed of light to be the same everywhere.
It’s because mass grows and becomes infinite at the speed of light. So if you shot a BB gun at the Earth at the speed of light it would destroy Earth according to Einstein and that kid from “A Christmas Story” who stuck his tongue to the flag pole. I think they both would agree. Hopefully without swearing. Thanks 🙏🏻 I hope this helped you out, but I thought it did say why, so I don’t know 🤷♀️ If you have any more questions I am ready. Thanks 🙏🏻
The speed of light is completely a function of the medium it traversed. Specifically as Maxwell showed in 1860 = 1/(sqrtf(u0)**2 * sqrtf (e0)**2). With u0 magnetic permeability and e0 electrical permittivity. These last two may vary depending upon medium eg free space supports faster speed than water.
@@utee72 so say the medium is the quantum realm then light could have a different speed limit there🤔🤷🏽♂️
@@BlackPDigitalMedia No the "realm" is our universe's free space and thus the speed of light is constant there. Quantum objects in our universe cannot defeat this restriction. Note again that different "media" eg water will transmit light slower as they have different u0 and e0.
@@spiralsun1 In EM radiation what is moving through space? If it is the photon, it have the energy h when it is emitted by an electron. Then the mass of a photon is h/c^2. If the photon is moving at the speed c then too it's mass have to increase towaards infinity. But it is not happening. It remains constant. Why?
"Why the Speed of Light is the Speed Limit" - but the video showed what the speed of light is, and how it is measured, but not why it is what it is, and not why it is the speed limit.
Exactly. I suppose nobody can answer the question posited by the title. Unclear why it is titled wrong given how smart the content seems to be. Clickbait, I suppose?
Das ist genau die Hilflosigkeit, die versucht, eine Behauptung so lange mit immer neuen Thesen zu untermauern, bis sie gesichert scheint.
Though I don’t implicitly doubt the conclusion of the final experiment, I’m having trouble understanding why it proves that the photon is moving at the speed of light with respect to the electron. It only seems to prove that it moves at the speed of light respective to the stationary detector, irrespective of the speed of the emitter. I don’t see how that experiment is demonstrating the perspective of the emitting electron at all.
Go back to the pitcher on a train analogy. The pitcher throws the ball at 100mph + the train moving at 100mph = 200mph to the observer. But only 100mps from the pitcher's point of reference. Got it? Ok, so the electron moving at c + photon emitted at c should = 2xc from our perspective. And from the electron's perspective the photon should fly away at c, just like the pitchers ball moves away at 100mph on the train. But c is constant in both frames, unlike the baseball, and in both frames the photon and electron move at the same speed which is c.
@@daviddeavours4909except time is slower when YOU are traveling at c
I would say that it is not a demonstration that different observers see light at a constant c. It is just demonstrating that any light generated from a source will be seen by us as the observer to travel at c whether the source of the light is travelling either towards us or away from us at c.
c is dependant upon time. If the emitting source of the light is travelling at nearly the speed of light then time will be slowed and therefore it will still see the photon travelling at c.
Thank you for this quite excellent vid on the "C" constant along with its bonus, strong History of Science flavor! My subscription was instant, if not as fast...
With regard to your gamma ray burst you mentioned, you stated that the photons arrived within a few seconds of each other. Now there are no particles in a wave but that gamma ray did induce excitment intophotons that you were able to register in your equipment as you stated. But at no time did thoes photons originate from the place that gamma radiation started traveling from.
Just like the ocean wave example you showed earlier in this video. the particle or boat does not move with the wave other than up and down with the waves amplitude.
Gamma rays are no different than that wave in the ocean and the particles we see are not visiable until that ray strikes something like a particle of mater that then sende that energy in all directions for us to see it as it stricks our retina in the eye and excits particles responsiable for our sight.
The analogy I use is the wave moving through the ocean with no particles in it until that wave stricks the beach and imparts the wave energy into all the sand particles it strikes on the beach.
But the energy wave it self has no particles.
This was that totally captivating and interesting. Even though I couldn’t grasp all of it. But I do understand it.
SR does not claim a speed limit for C - it simply says things can not accelerate through and beyond C - not that things are not already moving [unaccelerated] at beyond C - how come so many folks do not know this?
Because there are no tachyons, and you don’t need to know that to describe experiment .
@@DrDeuteron I guess there was no Higgs Boson either...until there was. Be patient.
We found the speed of light - how incredibly fast it was - but then we found out how incredibly slow it was - considering the size of the Universe,
Except Einstein’s theory never says you can’t go faster than the Speed of light. Einstein never even said it that is a construct created by all the rest of you.
This video was AWESOME. ❤ One of the few to actually talk about the huge leap in thought that light has a finite speed. We so take that for granted.
Ole Romer actually constructed a telescope with calibration to do the measurements then squinted through a telescope carefully night after night and figured that out. Just mind-blowingly amazing!
I loved how clear and carefully the topics were covered thanks!!! ❤
Dr. Don Lincoln has his own yt channel, in case you are interested in more of what he has to say.
Thanks for taking 30 min's of my life to hear all I could 10 years ago.
The speed of light being the same for all observers is telling us something deep and fundamental about the universe. Have often thought the same thing but this is the first time I've ever heard it said in such a direct manner. Thank you!
@Matthew Philip Well the short answer is I don't know, yet. Another thing that makes me wonder is photos traveling at the speed of light apparently do not experience time. If I figure it out I'll let you know or you'll hear about it when I pick up my Nobel prize. 🤣
The Speed of Light (C) is constant because the Doppler Effect is altering Frequency (F) and Wave-length (WL)
C = F x WL
@@terryrogers8965drop that photons don’t experience time. There are no reference frames for light, so it is meaningless, and adds no understanding.
There is always something faster. Always!
Loved this Thankyou.
A couple of things, all the standard model particles that "Occlude" need to be the same size (12 Planque ish).
The superposed nature of photon weight versus frequency...
The "Particle" and the QM field wave are always "there" it's the spacial collapse and expansion for the raw weight that is frequency.
So does the entire "magnetic" aperture of the photon disappear and reappear (Polarity question) ?
Lensing is likely another double aperture addition, but if symmetrical flow energy is the vector driver, the "longest" distortion and therefore the lowest pressure is on the wrong side, but the planet side compression is 12 Planque higher than the outside so back to a kissing hawking reaction over time spinning the lowest flow density aperture length to the outside, resetting after frequency cycle completion ? 😁
Love your work DrDon.
Thank you again
Bernhard
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
@@jamesh9174 Boundary not limit and yes space has a time dilation ratio compared to us of 9*10^70 seconds for our one second observed.
I wish I had you as my physics teacher. I had a D in physics, yet I was fascinated by it and still am.
The fastest thing in life is the depletion of my bank account balance, light don't stand a chance there
There is no limit, time just slows down
Yes, there is a limit.
You've convinced me. Though there are caverns in my understanding. But you are a superb narrator.
Thank you, Maur! We'll share your comments with the professor!
Thanks for the video, some good explanations, and there is a lot of them out there. I'm seeing this line of reasoning over and over again, and every time I'm left puzzled. It seems to me we have two different things here.
First, since we don't really have a medium for light, i.e.the very space itself is the medium, and if we suppose it's fixed (although GTR says it's not, but lets leave that aside here), then it's no surprise that it can't be pushed by anything. Because it's not really pushed (or thrown or whatever), it is more generated. That very fact is enough for us to say that the photon could not travel faster than the speed at which the space itself could spread the electromagnetic disturbance (that is very similar to Maxwell's derivation from two different permeabilities). So that part is pretty obvious.
The second part is what puzzles me, and that is hidden inside the following sentence: "..the electron sees photon traveling at the speed of light...". First of all, how we know this? I'd say that is not something that could be deduced from any of these experiments. I know it's one of the conjectures, but could you please say what exactly proves that part? And I think it is crucial. As I see this, that part is what makes the (Einsteinian) relativity so "weird" - it gives rise to time and length dilatation, effectively the usage of Lorentz's transformations.
The geometry of the gravitational field requires that the electron measures the speed of light to be c. There is no way to render a different result consistent with the results we obtain in the lab.
@@kylelochlann5053 ok, but I don't see that in the line of reasoning in this video. I'm just saying that from presented reasoning and experiments we cannot say that the source of light, traveling in the same direction as that light, perceive it's velocity as c.
I would really like to see explanation on that.
The fact that emittion of light is not the same as throwing a ball from the train is far more obvious.
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
@@darkososyt Correct, the video presumes a basic understanding of relativity, which isn't obvious to anyone who has not studied it sufficiently. The constancy of the speed of light is owed to the local structure of the gravitational field and originally taken as a postulate by Einstein on the assumption that the electromagnetic equations of Maxwell are correct. Nowadays the local constancy of the speed of light is taken as a consequence of the spacetime interval being null for light, i.e. ds=0.
@@kylelochlann5053 that's very interesting... For some reason I'm trying to understand this, and the more I watch videos on the subject the more questions I have :)
Anyway, as much as appreciate people that make these kind of videos, seems to me that there's always something missing in line of reasoning. And often there is a mix of things like "light between mirrors on a train" and some math equation which already have many other thing hidden in it. I'm a mathematician by education, so to me, if we assume something and then make equations that are the consequence of those assumptions, even if the equations proves right, that doesn't mean that our assumptions are true. Logically, from false assumptions you can deduce right conclusions. So I'm trying to learn what exactly are facts and what are assumptions, or consequences of assumptions. I mean, if we knew everything, there would be no need to question anything...
I had a great time listening to you. I unfortunately didn't learn physics,nor astronomy, but am very interested by it. So I rad and watch on Internet everything that is related to it.
Love your videos....reminds me of the joy of calculating particles in a box at U of Chicago undergrad, but that gamma ray burst example you gave was simply mind-altering / bending/expanding! Thank you, Doc, for your understated-profundity!! ;)
Once we connect with all energies and anti energies in this and other universes and dimensions, we will be able to travel at the speed of thought. Then, we can be everywhere at the same time. I'd have 100 of myself in every existence. Always learning and helping those who want it.
@@baberoot1998 work on people? I was just describing my point of view.
Surely from the perspective of the electron the speed of the photon is zero (based on the way you explained it)
No, in the frame of the electron the photon still moves at c. Of course, the explanation of Don Lincoln is wrong, as usual.
@@kylelochlann5053 Also in the frame of the electron, the electron and photon do not arrive simultaneously. Relativity of simultaneity.
From my probably messed up understanding, it must be due to time dilation at the speed of light from the electron perspective vs the outsider perspective with no time dilation.v
the michelson-morley experiment is pretty impressive
If we detect gamma rays from 7.5 billion light years away they must have started out with vastly more energy than we detected…
Why? They aren't using any energy to travel. Surely they are set in motion when they are released from matter, then maintain that motion until they collide with something.
Yes, because of 1/r^2.
“It’s not true for light, and we know this to be true.” So true.
Is there a theoretical consequence to traveling FTL? What would happen to matter if it were to exceed the speed of light (e.g., particle breakdown, going plaid, etc.)?
Nothing would happen and time (and all else) would be normal for you. You would be moving traveling a negative length and this doesn't make physical sense, and you'd be able to send messages to yourself about events that haven't happened yet. So, it's not so much a problem as that it is meaningless.
Once you go faster than light, there are frames where you are teleporting instantly (to outside observers), and more in which you are going backwards in time. Just say no.
I'm too dumb for this video, but thanks for trying to educate me.
Also, the rotating mirror type experiments to measure the speed of light are even easier (require less than 500ft, tho bigger distances is indeed better) to do than the ones mentioned in the video and get between 10% and 1% error depending on how careful you are in setup.
We did both in Physics lab. as well as the Cavendish experiment.
If we were to take as gospal that the speed of light is the fastest speed possible then does this apply only when it comes to normal space? What happens when space bends, stretches or condensed? Of course all things are relative. Since speed has a time component influenced by these effects, does that then effect the speed that light travels? There are times when it seems the fabric of space time can cheat the speed limit by being full of holes that allows energy to seemingly exceed the speed limit by taking short cuts across the universe.
The Lorentz factor really represents projections back and forth between the two frames of reference, if you interpret it as a cosine (!) instead.
The apparent "length contraction" and "time dilation" arise from the 2D length and time "vectors" ( both complex variables ) each pointing in different directions in their respective complex planes between the two frames of reference , the more the faster an object moves relatively to the observer"s frame of reference.
Gamma^(-1) = sqrt( 1 - v^2/c^2 )
So they don't shrink (contract) or expand (dilate) at all - it's their projections (!!!) - or their "presence" if you like ! - in the frame of reference of the observer that shrink or expands.
( and the other way around as well of course ).
As v goes towards c, gamma will decrease to 0 - in which case the length dimension of the object along the axis of motion is entirely "out of" ( not present in ) the length dimension of the observer.
Think of a "unit" circle in the complex plane with radius c and v along the imaginary axis (!)
Well said.
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
@@jamesh9174 Well, there is - but then we would measure different values for the speed of light from different frames of reference - and we don't (!!!), which is very counter intuitive and weird.
So something else "has to give" so to speak for that to be true - namely the concept of a universal time and fixed spatial dimensions.
They (now) depend on the frames of reference of the observers.
From the frame of reference of the photon it reaches our eyes INSTANTANEOUSLY from the light source, since no time is passing for it, as the spatial dimension along its direction of "travel" is contracted to zero length ( v = c, in the Lorentz factors ) - or its "presence" ( the projection of its length dimension ) is reduced to zero, as I prefer to see it 😉
@@Bjowolf2 I like this "something has to give"! This is exactly how I have thought about these matters. Nothing shrinks or expands but the measurement of these parameters. It is not necessary to think of a an object actually shrinking in the direction of motion, only that the measurement of such changes with relative velocity. Of course, my view here raises the question of whatever "actually" means in these contexts.
@@daviddeutsch3392 Thank you 🤗
What if a car could travel at the speed of light. Would the light from the headlights of the car be traveling at twice the speed of light? I would guess yes, but probably not correct. 😊
Also, if a car was traveling 60 MPH would the light from the headlights of the car be traveling the speed of light plus 60 MPH? I would think so, but that probably is not correct either. 😊
Physics is so much fun. 🙃
Very good video, though I think it did not answer to the question in the title. I saw another video about this topic on PBS SpaceTime where they tried to explain this question. If I got that correctly (sorry, I'm not a scientist just a poor electrical engineer) the takeaway of that video was that (and they were referring to some articles there) if we make some basic assumptions about the universe (and I'm talking about real basic stuff here, like the cause must always comes first and the effect is only later). So based on these assumptions it can be derived that there must be a cosmic speed limit with which NOTHING can travel faster. This speed limit is the speed of causality. And it happens to be that the light has this speed (and as a matter of fact because its stationary mass is zero it cannot go slower - I mean, in vacuum.).
Perhaps some video about this topic on this channel would be useful.
THE SPEED OF LIGHT IS THE SPEED LIMIT, BECAUSE NOTHING TRAVELS FASTER THAN LIGHT.❤
Rather than the speed of light it might be more accurate to label it the speed of energy.
I'd be really interested in a quantitative analysis of the risk associated with mercury in the Michelson-Morley experiment. I suspect that it would accord more with Michelson and Morley, rather than the modern practices. I suspect that Mercury is dangerous at elevated temperatures or when complexed in bio-chemically active compounds, but that room temperature mercury is far safer than smoking and driving cars, let alone rock climbing or hang gliders. Probably safer than living in Colorado.
My question is this: if photons have no mass then why would they be subject to the universal speed limit? As i understand it, the reason you cant go faster is that you gain an almost infinite amount of mass which would take an almost infinite amount of energy to move you at that speed. If photons have no mass then what would prevent them from going faster? Obviously it wouldn't be energy constraints. What did Einstein have to say about that?
It still does have energy constraints, but instead of mass, a photon gets its energy from momentum, its wave travel.
They actually follow a different version of the formula, E=pc, rather than the more famous one, with p being momentum.
Please tell your video editor that those side camera recordings are really horrible... they make these videos very awkward. Just use the front camera.
I advocate jail time for directors who do this. They would occupy cells near the people who do countdowns for everything.
PLEASE RESPONSE IF YOU ARE GOOD IN PHYSICS
At 23:00 it is mentioned as a conclusion that the photon is travelling at the speed of light to both, me and to the electron. But where does the conclusion come from that it travelled at the speed of light to the electron? Theres no indication for this, neither in Michelson-Morley experiment nor in the observations of the particle accelerators.
Imagine the electron flying above a still lake with the speed of light, dipping into the lake. The wave travels at the speed of light right beside the electron above. I don't get where the conclusion comes from that the wave travels at the speed of light away from the electron.
It is no the speed of light that is the limit, but the speed of causality that is the limit. The speed of light can vary depending on the material properties of the medium it is passing through.
This guy is a good teacher. Altho beyond the scope, my understanding is that measuring the speed of light in one direction is not achievable. It’s measured by round trip b/c of a problem with keeping two separate clocks perfectly synchronized.
In the experiment with the electron and the photon, both traveling the same, it has nothing to do with the “observer.” It has to do with the fact that the photon has no mass, therefore there’s no inertia, or centripetal force as pertaining to gravity. You can’t sling, or throw something that has no mass. Nothing to do with “the observers.”
The most elaborate effort I have come across so far to explain to the '"average Joe" why the Speed of Light is Constant for all reference frames
Wrt the final GRB, why was there ANY difference in arrival times?
Romer's discovery was a brilliant bit of work.
So I've always wondered. If you were traveling just 1 mph below the speed of light , and you take a baseball and bat that are traveling with you thru space at 1 mph below the speed of light. What would happen if you hit that baseball with the bat in the direction you are moving? Because from your vantage point you and the ball would be at rest but physically you and the ball are both moving thru space at just below the speed of light. So would the ball exceed the speed of light or would it just not move and shatter the baseball bat?
To the stationary observer it might travel at .1 mph less than c. To you, 100mph because of length contraction and time dilation.
@@AMC2283 To you, 100mph; to the stationary observer it might travel at .1 mph less than c because of length contraction and time dilation.
Nice explanation.
My only question:
This experiment to measure the speed of light with 2 electronic timers, is it not too simplistic?
(1) How far need they be placed apart knowing that the c = 300 000 km/s?
(2) How do we synchronize the 2 clocks at the start?
We can never know the one way speed of light, no matter what the method is. Let along with the method mentioned here. I feel you, bro.
Great presentation! as usual.
As far we know at the moment , at quantistic level there are many speed unesplained
Maxwell method of deriving the wave equation is in correct. Electromagnetic fields are generated by sources and the sources can not be set to zero as Maxwell did. This is because Gauss"s law and Amperes law have source terms. When the sources are included, this yields a inhomogeneous PDE wave equation, where the wave equation is set equal to a source term. Solving this PDE is difficult but has been solved by many researchers, yielding a nonlinear phase shift vs distance from the source dispersion curve. Applying well known operators to the dispersion curve, inversely proportional to the slope of the curve, shows that the phase speed and group speed are both instantaneous in the nearfield and reduces to about speed c in the farfield starting at about 1 wavelength from the source. From there the speed asymptotically approaches c but never becomes exactly c even at astronomical distance from the source. So the speed of light is nowhere a constant. It is just a good approximation in the farfield.
Thanks for the detailed explanation of the Michelson - Morley experiment.
And for mentioning that it was conducted in my home time of Cleveland. Ohio at The Case School of Applied Sciences now Case Western Reserve University.
I contend, whenever and wherever the opportunity arises, that, in a very real sense, my hometown is the birthplace of Einstein's theory of relativity.
There is a mismatch between the title of the video and the contents. There is nothing in the video to describe why the speed of light is the ultimate speed.
@ 0:13 what happened? Unexpected teleport side shifting is most jarring
How did you synch the two clocks on those light detectors that you used to measure the speed of light?
Yes! I wondered the same. It is my understanding, that we can only measure the "two-way" speed of light. This video seems to suggest different, that the "one-way" speed of light can also be measured. I believe that is in error. Great observation. 👍
The standard method is Einstein synchronization.
You just use the NIST signal.
"The speed of light, being the same for all frequencies and wavelengths, and the same for all observers says something very deep and fundamental about the universe. Mind you we don't know exactly what it is, but it is clearly telling us something." That is a profound and essential observation.
I do know exactly what it is telling us. It is that the speed of light is a boundary phenomenon between two different levels or regions or planes of the universe. On our side of the speed of light, everything travels at or below that speed. On the other side of that speed, everything travels faster, up to the light of that region, which is another boundary.
There are seven such boundaries, all held in the overall gravitation, which may be one of the things that can leak through these boundaries, and my guess is that may account for dark energy and dark matter.
What it tells us is that frequency and wavelength are not properties of light. They are consequences of the frame in which the light is observed. It really is that simple.
Always nice to see dr. Lincoln.
Speed of light is ultimate speed limit due density of space which impeeds motion of EM. Waves.
19:00 How does that disprove the aether? Doesnt it just show that the aether is uniform in all directions? Why would we have assumed that the aether would produce a different speed of light from different directions in the first place? Havent we just renamed the aether to "spacetime" in the 21st century?
Don Lincoln is wrong. The MM null result only shows that the ether is unnecessary. All that is needed is the existence of the gravitational field, which is not an aether, which is a magical entity that lives on top of spacetime.
@@kylelochlann5053 Every McGuffin in physics is just "magic" rebranded. Dark matter, dark energy... unproven, unwitnessed. Its a "thing", an entity, that stands in for ignorance. And they contradict. We came up with dark matter because we see saw too much gravity in the universe for the matter, and then we came up with dark energy because we saw too little gravity in the universe for the matter. Instead of questioning the gospel of Newton and Einstein, we merely took a dump on Occum instead. The amount of blind faith that the current cosmological community embraces is astonishing to me. Take 100 years of questionably-accurate galactic motion observations, and extrapolate it into the past thousands of orders of magnitudes beyond what any statistician would ever allow if accuracy were even a concern, and call the result "big bang". Lets also ignore all the hard evidence taken from observation that contracts the basic tools we use such as red shift (NGC 7603), the 10 B yo star, and other observations that challenge the scientism narrative. Then brand it as a theory when in fact its barely a hypothesis, just to give it a little extra pop culture credibility. Dont like spontaneous generation of life? Too religious for you? Supplant it with evolution, and then "invent" a "whole new idea no ones ever thought of before" that we call abiogenesis instead, to explain the origins of life. Hush, its the same thing as spontaneous generation. Quit calling concepts "magic" to distance yourself pseudointellectually from them, when youre just going to replace them with other magical things.
If I learn, in a relative and practical way that makes sense, what a light year is, watching this video will be the best 30 minutes use of my time. Look out universe and the Big Bang Theory 🎆 because I’m coming for you now.
Are you assuming the electron emits a photon in the same direction it is traveling? Surely the photon could equally be emitted backwards or sideways?
Seeing how we've left reflectors on the moon during the Apollo missions. When we shine lasers at them do we, like a sniper trying to hit a moving target, have to lead the shot?
I liked this video faster than the speed of light⚡️
Another very well explained upload - thank you.
I knew you were alive!
@@Rasta426 How did you know?
@@AmyWinehouse.914 when is youre next single coming out?
@@Rasta426 The day after you become funny.
Don Lincoln should NEVER talk about relativity.
Every video contains misinformation. In this one we have electrons moving at the speed of light. Seriously, wtf? He never gets to why there is a speed limit because he doesn't have the slightest idea how relativity works.
Interesting lecture. It causes me to ponder the subject.
Just one question from layman: While explaining the particle accelerator experiment at t23 you showed that the electron and the photon both reached the second detector at the same time. This showed that the speed of the photon was still c and not 2c. But how did you know that the electron observed the speed of that photon as also c instead of 0? To prove that the speed of light is same for all observers, you have to show both, right? That the stationary observer as well as the moving observer both observe the speed of the photon to be c?
The constancy of the local speed of light for all inertial observers is a consequence of the causal structure of the gravitational field and not something that can be covered in this video.
@@kylelochlann5053 OK, so shall I infer from your comment that this video does not show that the speed of light is same for all observers?
@@hanumantd That's right, it doesn't. and I disliked it for the clickbait title. Based on his other videos, I'm confident Don Lincoln never took a course in relativity and doesn't know the answer.
EDIT: Lincoln would have used relativity in his course work and professionally. In grad school the high energy group (the particle physics kids) could often calculate things in relativity quicker than we could, but they had no idea why anything was the way it was (and often had hilarious explanations of what they thought the physics was about).
Nice to have a real person explaining and not an AI voicebot.
Thank you for a your simple way of explaining complex phenomena!
Physicists had some interesting bloopers in history. One of them is naming the constant "c" the speed of light. Actually c = 1/√(ε0μ0) where ε0 is electrical permittivity of free space and μ0 is magnetic permeability of free space. Hence c is nothing but maximum speed at which vacuum allows electromagnetic wave / pulse to travel. Mind it, there's nothing called perfect vacuum in the universe.
The fact that light is an electromagnetic wave pulse (which behaves like discrete particles in some situations) is a special case of electromagnetic waveforms. Other cases like radio waves, x-ray etc. function in similar manner.
Great video👍
Thank you for your feedback, Peo.
Lucid and succinct. Strange but true. Thanks.
How would you see where you were going if you went faster than the speed of light?
Good question !
I think you wouldn't be able to even think if neurons in brain work via some sort of electricity.
Thank you sir! The speed of light made sense to me for the first time ever.
Speed of light has to do with a nature of space. We know that electric permittivity (epsilon naught) of vacuum or free space and magnetic permeability (mu naught) of free space are constant everywhere, that's why speed of light in vacuum is the same everywhere and independent of frame of reference. It is simply observed that way. It is one of the fundamental constants. The constancy of speed of light is one of two conjecture of the special theory of relativity.
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
This can't be true bc the millennium falcon made the Kassel run in only 5 parsects. but if it's on the internet it must be true.
THE PARADOX THAT DISPROVES SPECIAL RELATIVITY:
There is a triangle of lights which we will call A, B, and C. They flash simultaneously in the frame of reference that is at rest relative to these lights. There is someone moving at a high rate of speed from B to A. There is someone else moving at a high rate of speed from C to B. There is someone else moving at a high rate of speed from A to C. So A flashes first and then B flashes and then C flashes and then A flashes again. How can A flash twice? When A flashes has B already flashed or not yet flashed?
or
B flashes first and then C flashes and then A flashes and then B flashes again. How can B flash twice? When B flashes has C already flashed or not yet flashed?
or
C flashes first and then A flashes and then B flashes and then C flashes again. How can C flash twice? When C flashes has A already flashed or not yet flashed?
You start up saying that they all flash simultaneously. Then each traveler will only see one flash from each point but at different times. The travelers speed only matter to make it possible to see any difference in when the light flashes arrive and possibly also the color of the flashes.
Is this a joke?
You seem to be describing what different observers see and then asking how they can see different things. Relativity accepts that events that look simultaneous to one observer need not look simultaneous to another. Also, you could do this same experiment with Newtonian physics, or so it with sound. Or BBs.
@@vesuvandoppelganger You started up by saying that they flash simultaneously and by that I understand that if seen from a point with equal distance to all three points they would be seen as flashing simultaneously. Any person at anywhere else around will see the flashes when they come to them. Time = c/distance. None of them will see more than one flash from each point.
It is my belief that if an electromagnetic impulse (in this case photons) is emitted from a point in the universe this point is fixed meaning it doesn't move even though it is emitted from a moving object. Any movement can be noticed in the frequency of the signal but not the speed. An example it speed radar. I believe that you can't tell any difference if you check the speed of a house if tested from a moving car or if you are standing at the house and testing the speed of the car. Another example is the redshift from far away stars that supposedly move away from us.
Some people say that electromagnetic waves (including light) are moving in some quantum field. My question is: Isn't that just another name for the eather that has been disproved to exist? I believe electromagnetic pulses (photons) are energy pulses or quanta's that can exist on their own just like a small space ship. They are pulsating giving them the appearances of waves. This in my opinion would explain the double slid performance. That free electrons supposedly also show up as both particles and waves in a double slid setup would indicate that they are also wavy particles. They are much bigger and have gained mass and as such can be accelerated but also move at much lower speed.
The speed of light is not a speed limit, it's the fastest we can currently detect.
No, it is the speed of light, it has been mathematically proven.
@dhouse Lol, really? Do you have proof of aliens going faster than the speed of light?
@dhouse witness testimony is the least credible form of evidence. If you knew anything about science you would know that.
I have yet to see a single peer reviewed paper outlining how FTL travel is possible, and includes demonstrations.
Nor are there any papers with any evidence of extraterrestrial life.
So if all you have is hearsay, you have nothing.
@@Spugler2 How about some elementary particles like tachyons or gravitional waves ? Would you consider these as aliens, lol ?
@@paulcarfantan6688 neither have been demonstrated to travel faster than the speed of light.
I don't think tachyons are even real, right? I'm pretty sure they are still entirely theoretical.
does wondrium platform have subtitles in english and other languages?
Hi Alberto, yes we do.
Was this done in a single take? My goodness… this is great.
Video exploded my brain but I😊 loved it.
ALL matter in the universe is at all times instantaneously communicating to all other matter in the universe, no matter how many millions or billions of light years away, on the quantum level, via gravity, whatever gravity is. That communication is faster than the speed of light.
It’s nuts is what it is. Tells you that there is so much we just don’t understand. It’s wild.
Love this channel
So, if a train is traveling at mach 1, and then blows the horn, the sound will travel at mach 2?
no
It was a rhetorical question prompted by the logic presented in the video... learn to have some humor.
This was a very helpful and informative video. One thing was confusing to me and it may be that my understanding, prior to watching this video, was just wrong. What I have understood the statement "the speed of light is the same for all observers" to mean is that speed is the same for each respective frame of reference. Meaning, if I'm traveling on a shuttle in the direction of a light beam at 1/2 the speed of light, that beam of light is traveling away from me at the speed of light. But, to a stationary person, that beam of light is still only traveling at the speed of light. I thought that was how time dilation occurred. After watching the final experiment here, though, I have more questions. Having a beam of light emit a photon and measuring that speed from a single point of reference does not feel the same as measuring one (or even two) beams of light from different reference points.
That is for Transverse electromagnetic waves. And we will have to go back to the aether. I think it was Oliver Heaviside who simplified JC Maxwells 20 equations in the 4 know today as maxwells equations.
All propagating modes are transverse, but it works for near field effects too, it’s just that studying those fields only adds difficulties, not elucidation
26:45 Okay, but why was there any difference at all?
On the front of an electromagnetic wave an energy front travels also and it has its equivalent relativistic mass; hence it curves space. That is, it generates gravitational waves that propagate at the speed of light, the same speed at which the EM wave that curves space travels. But the fabric of the universe has inertia that opposes its curvature, it is an opposition to its displacement that faces light and that determines the speed of light (or gravitational wave).
Thanks
Excellent. I am looking forward to your video on the speed of gravitational waves. Since they are not an electromagnetic phenomenon, there is no obvious reason why they should also travel at c.
What if there is simply a speed limit in our universe for light or anything and that is what we see in the experiment and not that light is the same speed for all observers?
@@jamesh9174 That is in fact true. Light travels at the maximum speed that the universe will allow, and so do gravitational waves.
In the electron/photon experiment, what if you move the detector towards the photon? Will you detect the photon sooner than a stationary detector does?
Speaking as a Flatusist, all that M&M at Case and the acceelerated electron vs photon proved is if there were an aether, it doesn't pass wind. How about fill the vacuum of space with neutrinos that then function as dark matter and energy as well as being the medium that allows all starlight to travel everywhere, captured wherever a mirror or retina reside. No wind, light only becomes particulate when it interacts with something, the neutrinos acting as nothing, or existing materially in a different dimension. But I'm guessing, or gassing.
Thank you for what you do.