My bank uses the same theory, but vice versa. When the money leaves my debit card, it goes really fast. When something is to be repaid, it takes much longer.
It is, for bank, a convenient model to embrace. You'd be a banker, you'd do the same ! Now , of course, you don't believe Einstein really had any clue what was the speed of light. The number just fell into his hat. Actually Morley and Michaelson were trying in 1887 to measure the speed of light. But the 'ether" screwed up everything. Einstein just took M&M experiment result and declared that "ether" does not exist, and that froze everything in place including the speed of light.
LOL my bank is involved in this inverse of equities and is complicit as far as I'm concerned....I speak into existence and impose the maximum penalty for their impetulance with the application of the converse of consequence to the algorithms restricting my transactions and unleash the acholaids of irreverence to expand and proliferate the funds available to be unlimited everyday and to exponentially grow... please and thank you :)
This was a very fun present to unwrap. When you called me and told me to turn the camera on I knew something weird was going to happen and you certainly delivered. As long as I’ve known you Derek you’ve been destroying assumptions. Thank you for this friendship. It’s certainly enjoyable from my perspective.
Great video. Despite getting a physics degree and teaching physics for years, I never came across this or thought about it. I was treating the video mostly as a 'fun to think about' sort of video, but your point at the end is really intriguing.
Even after watching the video, I have a few questions. What terrifies me the most about the questions, isn't that I think that they'll find a way to solve the one way speed of light; but the fact that if I am thinking about these questions, someone else likely has already, and there is a reason these questions don't answer it, and when I try thinking of the reasons, it makes the whole concept seem even more bizarre than it already is. For instance, we are trying to measure the speed of light in a vacuum. But we could also measure the speed of light in a medium; intuitively there should be a relation between them. But the intuition must be wrong right? Or at least unverifiable. Which means even with an instantaneous vacuum speed of light one way, and a 0.5c vacuum speed of light the other way, there is some very strong asymmetrical physics going on when light goes through a medium. Even if I have a medium that slows light down to a crawl, there has to be a reason it doesn't show the asymmetricity in the speed of light. There also has to be a problem with colliding objects at relativistic speeds, due to the vastly changed special relativity formula. Two objects with the same insane kinetic energy relative to their stationary mass, can be travelling at two vastly different speeds depending on which direction they are traveling. One could be moving near instantaneously, while the other can be moving just below half c. Intuitively there must be some way you could use this information to solve the problem; but the intuition must be wrong, otherwise it wouldn't be an open ended problem. Probably the reason things act so asymmetrically weird if the speed of light in a vacuum is asymmetric, is because that isn't "just the speed of light", it is the speed of causality. It means cause and effect acts different speeds in different directions; and there is no experiment you can do that can get past the limitations of cause and effect. All physics basically goes bonkers such that the asymmetrical speeds will always work out. ---------------------------------------------- Anyways, other than my mind breaking, I do agree that the end of the video is very intriguing. A solution to figuring out if the speed of causality is asymmetrical or not, could exist in a unifying theory. So the mind breaking isn't all for not. Or perhaps the concept turns out to be pointless. As what does it mean if the speed of causality is different in two different directions? What is differences in time and space even mean if causality is different in two directions, aren't time and space dependent on causality. Perhaps the entire paradox of asymmetric speed of light is dependent on our own ignorantly rigid view of space and time? And thus unifying theory will have nothing to do with answering our fallacy of a question? Ugh, my head. Anyways, I can always find solace in that Hexagons are the bestagons.
I made a separate comment, but no one replied so ...here it goes: "I honestly have no idea what I am talking about, but ... can you use quantum entanglement to measure the speed of light somehow? The entangled particles are "already synced", so "hit" the one "far away" with "something" that changes it's state and observe it/measure the time on the one "near" you... and do the same speed of light test from/in all "directions", then just compare the times to see if it's the same. Only objection I could find to this not working is that I have no idea what breaks entanglement, so stuff like lasers, photons, whatever ... might not break it. In rest, it seems like a good idea. Obviously I am wrong, or else it would of been tried by now, but I would really like an answer for this, if someone could educate me. Like I said I have no idea what I am talking about, so don't jump me. :)"
Okay, I have a question is the solution of 10:00 in multiple ways correct to verify de one-way speed of light okay hear me out. 1. If you do this and film both the clocks you can see which one turned on the fastest. Or which one is further. Once again you need to time it perfectly by turning on the cameras at the same time. But this one could be possible 2. If you move the middle clock to the left or the right you would get another result out of it if the speed of the light is different if not you have done it. To this correct you nee to set the clock on both sides at 300 meters away from the middle I hope my English wasn’t that bad and that you understood my brain thoughts
Think one more time: "are distances AB and BA the same or they are measured in terms of light traveling time?" and you will get your sanity back. You can easily simulate the entire special relativity universe defining your (name A) causal boundary as now. It looks like "c0 towards you is \inf", and "c1 away from you is c/2" and for every BA synchronization event all time travel distances pointing to you are just zero, and still (c0 dt0)^2 = dr^2 = (c1 dt1)^2 the metric invariant your coordinates must obey. This kind of "absolute" distance independent from your speed of light choice came from you actually postulated the object B being at the same location for AB and BA synchronization events but how can you define "the same point" within the experiment? Observer from Pluto will surely note your signals were sent and received at different points of space. And here comes the answer: how can you measure any kind of "directional" speed of light if you can not provide the same distances in different directions?
I am an RF engineer. We use the two way speed of light to determine the wavelength of a radio wave. We use the wavelength to define the lengths of transmission lines to do things like impedance transformation. Although, these applications only involve the one way speed of light, the applications still function as if the one way speed of light were exactly the same as the two way speed of light.
That's actually a proof itself. This video doesn't make much sense to me. There was also synchronized pendulum that can be used to time clocks together as pendulums sync by mechanical energy
@@InsaneSibs The pendulums wouldn't be perfectly synced. The pendulums would always be slightly not synced up just because they transfer energy to each other at the speed of sound, way slower than the speed of light.
Lets be honest or make a bet... when the time comes, it will be proven that the speed of light is same for both directions, its pretty obvious. Right now "Veritasium" got the free hall pass for making wild assumptions since speed of light can't be measured with synced clocks.
@Steven Moore Since I am the moving observer, it's my timepiece that runs slower. Only when traffic is unusually light can these relativistic effects be mitigated. It's just physics.
Would like but your count fits into 8 bits exactly, don't wanna be the one to change that :) *Edit* Damn someone changed it, oh well, added the like now it no longer fits into a perfect 0xFF
The part where you talked about distant objects, since we see the same type of galaxies in their early life in all directions. That proves that if there is any difference, it would be extremely small.
I had the same thought, but it still has the same issue. Unless we're wrong about the big bang, it means any galaxies 13+ billion light years away started more or less at the same point as the matter that comprises us. If the ancient galaxies off our north pole are instantly sending their light back to us, they've also been under severe time dilation as they've moved away from us for 13+ billion years, which means they've evolved far more slowly than the galaxies off our south pole. Our real time view of them shows them in their proto stages, which is exactly what we would see if the speed of light was the same in all directions. There's just no way to avoid a two way trip and maintain any kind of certainty about simultaneity. Even if we assume the big bang didn't happen, everything is still moving away from us, which serves to counteract any lopsided c shenanigans.
Also redshift being the same in all directions would be another "one way" measurement proving there is no preferred direction. A preferred direction would show up as one side of the sky redshifted more than the other. Redshift is an analog of travel time because it takes time for the space between the star and here to expand, causing the redshift.
@@ninehundreddollarluxuryyac5958this is the answer to this video. The redshift being basically homogeneous means light must travel the same from all directions.
I know for a fact that the speed of light depends on direction, because sometimes when I sit at a traffic light I can see the BMW driver behind me flashing before I see the light turning green.
Light from distant stars is red shifted the same amount in all directions. If you are seeing light from one direction instantaneously, it wasn't travelling long enough to get red shifted at all because the space between us and the star would not have expanded at all in that (lack of) time. Even a small "preferred direction effect" would add redshift to one side of the sky and lessen it on the other. This is a one-way analog that allows comparison in all directions. You're welcome, I hope this puts your mind at ease on the topic. If you are still skeptical, explain why, because redshift requires time as far as I know.
Have a big clock display of a super accurate clock suspended on a roof or tower. Aim two cameras at this display. Let the clock run, its start time doesn.t matter. Have the first camera triggered instantly, the second camera triggered by a beam of light activated the same time as the first camera. Compare the photos to see yhe time difference. Depending on how powerful the camera, depends on how far away you could feasibly place the static clock and second camera
@@Raythe but because the speed of light is different for different directions, two cameras will see differently delayed images so that the time difference you see in the images will be c.
Get two clocks that are 100 meters away from each other. Start them at the same time. Shoot a light across from one clock to the other. When the light reaches the first clock it will stop. When the light reaches the second clock it will stop. You have 2 times and you subtract them to find one. And convert to the larger scale
They probably don't even have the intelligence to understand what you are telling them so it's easier for their little brains to consider you crazy than to accept that they are stupid.
@@r3kpwner303 Not true. People have different things to focus. No one has the capability to be smart in every thing. Debunk this: There is no way to measure a people's intelligence.
They couldn’t care less about figuring stuff out. All of these stupid ideas are absolutely incorrect, and have been put to grave with actual experiments over 100 years ago All they care about is showing their sponsors how many people watch their anti scientific horseshit Go buy some kiwico and support the huckster
@@MusicNewb absolutely, there were two brilliant scientists who set out to measure the difference of the speed of light in different directions over 100 years ago. Their names were Michelson and Morley and if you search “Michelson-Morley experiment” you will find many articles because what they have measured was an important stepping stone in the history of Physics
@Science Revolution , You list SO many things which are not true here that I won't bother to point them out. You might as well be traveling instantaneously.
@Science Revolution If you write an article and prove that mathematically, you could actually become a reputed scientist. Go ahead and do that. That's the beauty of science, all scientist have that in their minds, a sentence that says: "we could be wrong, and we probably are". We have like 3 centuries of science and look around you, look what they've already done! 300 hundred years is nothing compared to the time that our species is in the planet and absolutely nothing compared to the age of Earth itself. Stop comparing Science to Religions, they have nothing to do with each other.
Guys don't reply to that revolution guy,he/she literally mass spams this exact paragraph on all science related channel nowadays along with bunch of his flat earther friends, Well he's/she's literally questioning the very science which is allowing him/her to watch this video on his/her device, it's like if Elon Musk's son starts saying neuralink is fake. I was watching a video where a psychiatrist explains why these kinda people exists who claim the earth that it's flat or all the theories are bs , it's like they want to feel special as if they possess a knowledge which is hidden from the general public,it's like the film 2012 where only few people knew about what will happen actually in the start ,these want to get a feeling like that forgetting the difference between real life and Christopher Nolan's fiction scriptures , however this is also a state of mental illness which must be treated and not like back in 1700s when if someone started seeing ghosts , people started excorism or drowned him/her in the water lol
If the pulse to start the second clock us traveling at the speed of light(2:27), then why can't you just subtract the number of seconds the second clock has been running for from the first? I feel like this is a stupid question and I'm missing something...
@@mahirshyam4127 because if the speed of light is potentially different in both directions, then how could they know how much to subtract it by? The experiment would be trying to measure the speed of light, but you’d need to know the speed of light in order to know how much to subtract the second clock by. For example, imagine trying to solve for the length of the hypotenuse of a right triangle, but the only information you’re given is the length of the bottom leg. Asking why you can’t just subtract the speed of light from the clocks to get the answer would be kind of like saying “why not use the length of the bottom leg and *the length of the hypotenuse* to find the other leg? Then from there, just use this other leg to find *the length of the hypotenuse.”* Hopefully this example makes sense, I’m not the best at explaining things.
I think a lot of people will watch this and have the attitude of "well of course it's the same in every direction, why wouldn't it be?" which I lean towards. But the point at the end is the most important part. The fact we can't measure the one-way speed of light is itself a huge clue (possibly) about how the universe works that is staring us in the face.
The answer is easy, if u wanna measure the time delay in one direction, u send an impulse between this two clock's in each of this two directions and u will see if one starts later .... Quick maths
@@babylebron6119 I'll take it you didnt watch the whole video when you wrote this. He explains that the problem is that it remains unknown if light travels the same speed in all directions.
I am an engineer and was working on time synchronization between two devices on the same network. We encountered cases where network delay from A to B is higher than from B to A and such cases resulted in inaccurate synchronization. I was working on solving this problem and after watching your video I realized it’s essentially the same concept- sending signals from earth to mars is like sending network packets from A to B. So the conclusion was, without the help of any external device it’s impossible to accurately sync time! Thanks a lot for your video :))
How does this affect the light year as a measure of distance. everyone is fascinated by it as it, because the observations of the star Betelgeuse for example, suggest that it is ready to explode into a supernova, but what we are observing occurred 600+ years ago?? I've also seen deep space observations of a binary star system when one of the stars occults it's twin for over 10 minutes, which blocked the light completely, it wasn't picked up by the sensors.. but as they eventually moved and came back to view, it was instant... i think that was 1000's of light years from earth, so why was it instantly seen and formed the same histogram reading it was prior to the occultation. I'm no expert it has all fascinated me since i was a kid, so if you have any ideas, or let me know if ive got this all wrong.
We dont need a clock at all. We shine a laser moving at the receiver at a speed of 100 km/ h and observe a Doppler shift in blue. We do the same thing from the opposite side, we observe exactly the same displacement. Congratulations! The speed of light is the same in both directions :))) Easy.
@@rainmansound1 you need clocks to measure the speed of 100km/h. And if the speed of light is different in different directions, your measured speed of 100km/h will also be “actually” different
But we can synchronize clocks across vast distances (this is the whole reason GPS works, every clock in the GPS network is Synchronized because they know their exact position and relative velocity to other satellites, thus they can adjust their internal clocks to negate time dilation... because they have synchronized time, their beams to GPS devices with their exact time stamps, allows the GPS device to exactly calculate how long it took for that beam to reach the device from the orbiting satellite and thus we have very high precision triangulation of location... all because these satellites have synchronized time.... The thing Veratsirum is blatantly ignoring is that the reason two clocks "can't" be trusted is because relative to each other, their individual velocities results in time dilation, but this time dilation can be compensated for because we have the equations for general relativity(how we can synchronize GPS)... What he's saying is a barrier to recording the speed of light in one direction, is actually proof that the speed of light is the same in all directions and not just a convention.... TIME DIALATION.... even if the speed of light in one direction is slower than the speed of light in another.... Special Relativity tells us that Time Dialation kicks in... This will expand and contract space time in either direction, so that the resulting measurement (Distance of time) will always = C... this will happen by either contracting space, or elongating time, but the result will always come out at C (and is proven experimentally, as well as the basis of much of our technology for space travel, GPS, and quantum sciences)....
When you remember that time and space are actually linked in spacetime, it's rather unsurprising that it is hard to align / synchronize time when spacial distance is large. The concepts of simultaneity and spacial proximity are the same thing in spacetime. Further, I don't think that photons actually fly through space for a specific amount of time "until" they reach us. The existance of photons is only ever relevant when we interact with them. In a way, the "observed" photons/light are the interaction between an atom of a far star and an atom in the retina. This interaction could be computed by the "universe engine" in the same "time"step /instantly.
after years of religiously watching you when i was in high school, and as i am now about to finish a computer engineering degree, i would like to thank you for rekindling my passion for physics and understanding the observable universe
@@muazshash9802 thank you!! well my major is supposed to be a combination of both, so i took a lot of electronics courses which i ended up absolutely hating lol. so i'm focusing more on personal development for the software side. wish i could take more CS courses strictly but i gotta finish my requirements. what about you?
When we look at the stars, we look back in time (at least if c is isotropically constant as usually assumed). The furthest look we can have is to observe the microwave background, isn't it? And as it changes smoothly the speed of light should change continously depending on the direction. Moreover, if we assume c is infinite for a particular direction, we should therefore be able to see indefinetly far into the universe and thus indefinelty much galaxies. So, if we compare the galaxies visible in different regions of the sky, we should be able to estimate an upper limit for deviations from an isotropically constant speed of light?
Arguably, the distance of those far away galaxies cannot be determined if C is not constant. So basing the value of C on how much more "primitive" a galaxy looks depending on how far away it is only reinforces the unknown presented in the video. If we look at different patches of the sky we see that there is no standard/constant change in the development of those galaxies, and this is generally explained as the result of gravitational lensing. However, the same observation can be explained by the variability of C as well.
I was just wondering the same thing. If direction matters, wouldn't we see parts of the sky more or less as what they were some time ago (and therefore having dark gaps in which light hasn't reached us yet) and at the same time other parts that are much much brighter since that direction is the "realtime view" (if we can call it that) and we see much much farther away (and more stuff too)? Anyway, cool video as usual :)
Have a rocket exactly half way between earth and Mars. The ship will send one message to earth and the other the Mars and then instantly back to earth. You would expect that the message that was sent to Mars first would take exactly three times as long to reach earth as the one sent straight there. If this does happen then the speed of light is the same in both directions.#big🧠
What relativity actually tells us about is that it is meaningless to even talk about "right now" for other observers, time is trully relative. Synchronisation problem only reminds it for those in doubt
This. People would understand relativity much better if they were introduced to concept of locality earlier. There is only one real "now", which is _my_ now.
Here's an experiment that I don't know has ever been tried. Set up 3 points on a line A,B, and C have them be equally spaced apart. Using the speed of light from the round trip measurement we synchronize the clocks at B and C from A that way we know that the synchronization signal only traveled in one direction to both clocks. Then measure the speed of light between B and C in each direction separately.
This is one of the things that I love about physics. As a quote from my teacher “nothing can ever be proved there can always be some thing that is impossible for us to measure. This is what makes physics and all other things related to it able to revision”. There could be thousands of things that are impossible for us to prove because our brains could not possibly comprehend it and our technology, currently, could not feasibly measure it.
When I learned that under any circumstances, some form of energy will always go to waste. Since high school, I have always done imaginations on how we can build a device where 100% energy can be used. Like creating a light bulb that emits heat but using that that heat to power another device. But then I thought I don't need all the light that the bulb is producing. So yeah my mind always boggles in these imaginations. But it's fun to invent different devices in my Brain nobody will ever know.
There is a logical answer to this dilemna ... Reflected light is still light, therefore it travels at the same speed because it is the same... Thing which is nothing more nothing less it is just "LIGHT" KISS keep it simple stupid.
But isn't the speed of light constant? The entire basis of C is that it is unchanging. If you measure it in one direction, well... you've measured it in all directions. It can't change.... unless all of that is wrong and C does indeed change. If it's not a constant, well, that breaks a lot of equations, doesn't it?
@@deydraniadiancecht8298 That's the point of the video. That it is the definition, not the fact. And that it breaks none of the current laws of physics as long as the average is 'c'.
If light is Infinitely fast on the way back wouldn't we see reflections of light from far away galaxies and there would be no observable universe barrier?
Use a ultrasonic wave in the middle to activate the 2 clocks. We know sound travels the same speed in both ways. Measure the distance of the 2 clocks based on the speed of sound and use this as the activation time for both clocks. Then shoot the beam of light.
I would guess that either time dilation or length contraction will cause the signals to arrive at slightly different times no matter how precise you are.
@@epicvillain8308 No but the dopler effect has, even though it works in the driver's favor. Far as I know this argument does not work anymore because of that factor (I just drive a truck though 😅).
Hey, just to let you know someone else in this comment section named Nihab Khan copied your exact comment word for word soon after you posted. Control + F to find the bastard. Go give him hell lmao.
Also there were two nobel prizes awarded for breaking the assumption scientists had about the charge parity and time simmetries so this wouldn't be a first but would probably be one of the best
You could just move both clocks at the same speed for half a mile then measure the exact time the light was turned on, and then the exact time it reached the destination and do the math
I got a ideas: 2: get a câmera, a lazer, 2 servo,a rod or a beam, and a timer. Set everything on top of a servo to rotate a little bit every Second and the other servo to counter-rotate the earth's day night cycle, place the Rod(or beam) in the servo and the lazer pointing (not in the Y Axis (up and down))) in the center of the contraption and the câmera on the other side pointing to the lazer but a little offset to the side (só the lazer dont hit It). Program the lazer or the câmera to shoot at a time while It rotates. You can place some flags around tô see the derections, but the places where You cant see the lazer You Will know where the light is faster
I absolutely love when people can take something ordinary and make us step back and see how much we don't actually know! Even if you can't confirm or prove the knew idea. The greatest discoveries are made when people are willing to challenge the status quo. Thanks for another amazing video
Actually they (in error) took something pretty simple and made it unnecessarily complicated. The solution: Now that we have measured the two way speed of light, we can measure it one way. An observer on Mars can be told that precisely at Noon their local time, that Earth will send a communication. Precisely at that Mars Noon (which Earth also knows on its own clock's time from a previous two-way measurement to synchronize the clocks). Earth sends the communication. Mars then records when the communication arrives and compares the speed indicated to the assumed speed of light (based on the existing two way precedent of nearly 300m M/s). This tells Mars exactly how long it took the light to arrive - and whether it matched the assumed speed of light or took longer or took less time to reach Mars. And if we furthermore allow the communication to reflect back to Earth, Earth can use the same method to record that signal's speed back to Earth and show whether it matches the traditional assumption. To verify this, all Mars needs to do is confirm later for Earth observers at exactly what time the reflection on Mars occurred. This allows us to verify the speeds each way individually and whether light was slower or faster in either direction.
This channel is awesome. It digs into fundamental issues in physics - verging on philosophy (ontology and epistemology) - within five minutes of the start of the video you’re right in the trench. But you’ve never been left behind, the issues raised are never inaccessible. Supremely good work.
@@Sharmajay69 We know the speed of light in a vacuum to a specific approximation, and we know the average distance from the sun to the earth. So we can say that light leaving the surface of the sun reaches the earth in about 8 minutes. This video is about how our measurement of this speed can never be exact because it’s physically impossible to set up such a measurement. But we can work it out approximately. I did it at school using a 100m electrical cable haha
@@jam-trousers i mean light travel in one direction in vaccum and we know the distance and time to reach the earth. So we can measure speed of light in one direction. But versatium is saying its not possible. Can you pls explain me in simple layman's term. I am novice Thanks in advance brother
Found this on @Brian Koberlein's blog: "Then in 2010 Jason Lisle revived the idea of anisotropic light. If light moving toward us travelled at infinite speed, and away from us at half the traditional speed of light, then it would allow the most distant light in the young universe to reach us while still agreeing with relativity. As crazy as that might sound, Lisle is right in claiming that such an effect would be indistinguishable from relativity, and this has made the work popular with young Earth supporters. However agreement with relativity isn’t enough. If light did actually reach us from distant galaxies instantly, we would expect galaxies at all distances (or more formally redshifts) to all look the same age. In fact, what we see is that more distant galaxies are younger than closer ones. If Lisle’s idea was correct, we wouldn’t see the magnification of distant galaxies due to cosmic expansion, nor fluctuations in a cosmic background, nor galaxy clustering in agreement with dark energy, nor a host of other observational results."
This is exactly what I was thinking. I'm curious if Derek has an explanation as to why we still observe distant galaxies the same way in every direction if lightspeed would vary based on direction?
The notion of instantaneous light speed breaks all of physics, unlike as is reported in this video. SR and maybe even GR would remain the same, but QM would explode instantaneously. You have to realize c is better understood as the rate of causality, not just the upper limit for relative object motion, let alone the ‘speed of light’. Much more likely then, if an asymmetry exists, it is a very subtle one, otherwise you’d run into CPT violations, and also have to extinguish the conservation of linear momentum - which itself predicates all other conservations.
@@joshandromidas The thing is, that if lightspeed fluctuates depending on which direction it travels, we'll still see different age of galaxies, because of the difference in speed, so it'll look the same as if lightspeed is constant.
So wouldn't your comment then prove that there is no direction in which light moves instantaneously? Also, considering the uniformity of the cosmic microwave background, wouldn't that show that the speed of light is indeed isotropic? Any directionality of the speed of light would then show in the CMB, right?
You can synchronize 3 clocks, put two of them at point A and one at point B; let the first one turn off as the light leaves it to point B, the second one turns off as the light reaches it from A (connected with a light sensor), and the last one turns off as the light reaches it from B (also connected with light sensor)
"To measure the one-way speed of light, we have to know it" has a ring of Gödel to it - a self-referential truth that can never be proven within the system. Keeps me up at night...
i think self reference contributed to many unsolvable things we have currently. turns out we need to start to look more into ourselves to know everything out there
It is easy - set 2 sensors that send pulse when light passes thru them to perpendicular single clock, so there is no need for synchronization. Path from each sensor to clock and path direction should be same, so delay betwedn pulses will express exzctly time that took light to travel from first sensor to second - that's it, you will measure one direction light speed. Can make a such measurment in several dirdctions just to verify that result is same
you don't need to know when exactly they send it - you just need to measure delay between 2 pulses. Since each sensor sends its pulse in same direction for same distance , so time of travel of each pulse to clock will be same and delay measured by clock will express exactly time that took light to travel from sensor to sensor
Well, c has a defined value, so the formula will allways be correct. The video is about measuring the speed of light in one direction. C is just dividing by 2 the time used by a ray of light going from here to there and returning here. So if from here to there light travels at 2c and from there to here at 1/2 of c, the average is.. c
Have a rocket exactly half way between earth and Mars. The ship will send one message to earth and the other the Mars and then instantly back to earth. You would expect that the message that was sent to Mars first would take exactly three times as long to reach earth as the one sent straight there. If this does happen then the speed of light is the same in both directions.#big🧠
@@jontisaurusrex9851 In order to measure that, the clocks on the ship and on earth would have to be perfectly synchronized. How are you going to do that?
@@Anton-cv2ti Maybe one way would be to accurately calculate at what time exactly the ship would be in a specific place between mars and earth and when the ship knows it's in the correct spot, just set the time to the predetermined on earth time, then proceed with the experiment suggested above.
Rotate a tube or a some type of gear with slits on opposite sides and have a detector to see if light made it through. At a certain velocity of rotation light won't be able to traverse it. That speed and however large the slit is (the distance it would need to rotate to stop the light from making it through) gives you the time. Use that time and distance between the slits to get the speed of light
i was stumpped by this video at first for a long time. thinking there was a dire need to confirm lights single direction speed. but i don't think there's any need to do that, I've realized this video is misleading. there are tons of examples in physics that confirm the speed of light is the same in all directions, DESPITE not being able to measure it as of yet. the most notable being if the speed of light were different from different directions, black holes would represent that, as the event horizon would elongate toward one direction and be flatter in the other. making cone-like, egg-like, or junior mint like (a dimple on one side and a crest on the exact opposite side of the dimple) shape pointing to the fastest direction light can travel, because it would take more energy to suck in light in from that direction. instead we observe the event horizon to be perfectly spherical confirming light travels in all directions and polarizations with the same amount of energy and mass.
@@Ae3lolz I don't believe that is correct. Link? Misleading? Everything he said is true, you can't measure it , sheesh. What are the tons(misleading?) Other examples out there?
All these factors suggest that time is the determinant of the speed of light, and it is well-known that time moves in one direction. Consequently, the direction of time is directly proportional to the speed of light. As such, light should travel faster when following the direction of time and slower when moving in the opposite direction or making an angle greater than 0 degree.
Why is Donald Trump pretty and I am not? But why does he only have a wife but I have TWO HOT GIRLFRIENDS who I show off in my masterpiece YT videos? Do you know the answer, dear pat
To quote or at least paraphrase the late great Douglas Adams: Nothing travels faster than light - except for bad news, spacecraft powered by this technology were rather unpopular when they arrived at their destination.
Okay, I've got a few reactions to this: 1. I feel like Michelson-Morley should have been brought up at some point. I want to say, "But didn't the Michelson-Morley experiment disprove the existence of a preferential direction for the speed of light?" but I'm guessing either something about the measured directions being orthogonal rather than parallel or something about the fact that both directions were using round-trip light would destroy that notion. 2. How do you explain something like the CMB if the difference in the one-way speed of light is as extreme as c/2 and instantaneous? Wouldn't that mean that one end of the Universe was extremely hot and dense 26 billion years ago and the other end is identically hot and dense right now? How does that make sense? 3. Could we measure the one-way speed of light if we could make use of some egregiously curved spacetime? Like, measuring light orbiting in the photon shphere of a black hole, or if we could manage to create the 3D equivalent of a torus (I suspect that might require exotic matter, though)?
I asked myself the same thing. Similar to your question 3: Imagine a supernova in a galaxy far away. Now imagine a black hole between us and the supernova. We will observe the light twice: Once on the left and once on the right side since the light will be bent by the black hole due to gravitational lensing. Now if light was traveling faster in one direction of space, shouldn't we see a delay between the light on the left and the right side?
Regarding the second point This is something that bothered me as well. I'm pretty sure that can be ruled out if we remember that The Observable Universe is bound to speed of light and where the speed of light is infinite the whole infinite universe would equal The Observable Universe. And that's why it looks that hot and dense? Does that make sense??
@@matthiaskuhr8417 yes, you would see it twice with a delay. We are currently observing a star the went supernova on the other side of a black hole and so far 4 images of it have appeared and they were able to predict the week the next one would show up.
@@matthiaskuhr8417 draw the diagram. The light bends one way and then bends back to reach you; on the opposite side of the black hole, it bends in the second direction first, and then back in the first direction. You’re measuring the two way speed again.
If you think speed of light is different for two directions, it’s your job to prove it. Not just telling people to prove the speed of light is the same. You raise a hypothesis, you prove it. So what if I say there is a ghost standing right next to you, and tell you to prove me I’m wrong otherwise the ghost is true ?
This is an awesome, very thought inducing video. A follow up video on what could be causing this potential asymmetry would be fascinating as well. However the centered clock synchronizer at 9:50 doesn't exactly equate to the GPS example he introduces next because in the first example, the A/B clocks agree (correctly) that they are stationary relative to the other. In GPS, the clocks are in relative motion. This creates a larger problem when trying to keep the satellite clocks running at the same "rate" as the ground clocks. They in fact have to run at the same ongoing rate for the system to function accurately but this (like it or not) is in contradiction with special relativity. I cover this in my twin paradox video.
So here is an idea. Two mountaintops. On one you make a light blink. On the second one, where you are, you place another light and you synchronize the blinking. So now, they are blinking exactly the same. Now take a hike to the other mountaintop. The lights won't blink exactly the same. Measure the time difference, measure the distance. Calculate the speed. Do this in a few different directions and compare the outcomes. Voila. Happy to help.
@@Future__martian Fair point. I made a poor choice of words. I was referring to laser-based detectors. In addition to radar, police commonly use laser guns as well. These are completely different than radar guns. They function differently from the police officer’s standpoint, they have a number of advantages and limitations compared to radar, and they require completely different tools to combat as a driver. Thank you for point that out.
There's 2 types of devices used by police to determine a car's speed. Radar measures the doppler shift in the signal and uses the shift to determine the speed of the vehicule. Laser ones, fire a laser at your car and it bounces back and then it does it again and measures the difference between both interval. So it's measuring the 2 way speed (going to and coming back) and not single way. So even if light was slower in one direction it wouldn't change the final result.
Here’s a way to, if not disprove it, make it demonstrably less likely: Interstellar astronomy. It’s a one-way trip for the photons in all directions towards Earth. If c was meaningfully different in different directions, we would expect to see a very distinct difference in what we see from each side of the sidereal universe. One side would appear substantially younger to us than the other, in terms of types of stars and galaxies we’d see. One side would also be substantially denser with visible objects, because the Observable Universe would be longer in that direction. Which to my understanding is not what we see at all. That only rules out a really significant difference, but it’s a start.
I’d love to hear thoughts on my hypothetical here: If you were to take a circular object of a known circumference, then wind a specific length of fibre optic cable around this object, send a pulse of light at the same time as beginning a clock, with the clock being at the same location on the object as the laser pulsing the light. Using this, you would be able to average the speed of light based on the direction the circular object is parallel to. If you were to then rotate the circular object about the Z-axis to an angle that is different than the absolute value of the starting angle, then measure again, you would be able to conclude whether or not the speed of light is the same in a given direction.
@Florentin sound happens because of pressure waves, which happen because of the fluid (air?) Moving, which is made of various particles, that interact with each other by means of electrical forces. And those are linked to electrical fields, which propagate.. at the speed of light... 🙈 Therefore I guess it's checkmate again
Brow if they send massage to Mars at 12:00 and send another massage to Mars after 20 earth minutes. So the man in the Mars kan take the first massage at 12:10 and he can take time and he can se how long it will take to get the other massage so he can find the light speed. It is to easy. Believe me
@@kevoramma great point! Thank you for using TH-cam comments to help correct my grammar to be more in line with your taste. Tell you what, give me your email address and I’ll send over some other comments I want to write and you can give me some more feedback before I post them 👍🏻
Without reading all of the comments. My suggestion is to use 2 lasers and time each direction. separately.Not being a Smarter Every Day or a Veritasium, I am however an Every Day a Verispasium. Obviously this has already been thought of. The 2 of you play off one another very well, it's a pleasure watching both of you.
only by asking a dumb philosophical question that reality refutes on every level... This is why philosophy is garbage. Possabilities dont matter, reasonable probabilities do.
@@terryfuldsgaming7995 bro my mans said Einstein himself did the two way measurements and he has many points in this video based on relativity not philosophy
@@terryfuldsgaming7995 Reasonable? Take a good, hard look at our current understanding of physics and come back when you're ready to call it reasonable. The very reason philosophy _is_ interesting is precisely because there are possibilities about reality that sound completely bonkers to us, and yet there's strictly nothing explicitely fordidding those possibilities... so what rational reason could you possibly have to dismiss them entirely? Symmetry? That sounds like a good argument, but there are plenty of situations in the real world where symmetries are broken. You could say that, on a purely a priori basis, more symmetrical options are more likely, but because it's a continuum between being completely symmetrical and being completely asymmetrical, without changing anything about causality, physics or your everyday experience (since if there was a difference you could measure it), the probability that the situation is _perfectly_ symmetrical would be zero. Even as a thought experiment, this entire thing is fascinating because it completely breaks our intuitions.
Don't you just love it how Destin was spelling out how they measured that ball's speed and immediately realized what you were up to? 😸 Can't help but love that guy
How about trying a game of mirrors? Place the clock and the mirror at distance X and measure. Then, add another mirror, where the first reflects to the second and then to the clock, keeping the same initial distance X between them. In the end, you can subtract 2 paths from the first test from the 3 paths of the second test. Leaving only one part remaining.
But he answered the question himself... around 13min he explains how it is possible to measure if the speed of light goes faster one way than the other...
14:01 actually explains why it's unknowable since all the possibilities can actually be possible. Light could move at the same speed in all directions and light could move a certain speed in one direction and almost instant coming back. There's no way to prove which is correct hence it's called a convention. Meaning everyone just agrees that light moves in a certain speed equally in all directions to make things easier.
@@kelvinnueveanimeguitar1983 To be honest it almost broke my brain too but I'm happy to say I finally solved the light measurement puzzle and posted a video on it.
Doesn't he solve the problem with the mars example? When we travel to mars that experiment can be done. The clocks and be reunited on earth and if they are the same we know the speed is same in both directions, right ??
@Meggion Well, yes... Thorne was credited as the scientific consultant for the movie. Of course Nolan didn't invent the scientific concepts for Interstellar. What's the point of your comment?
Use camera A for a live video call from camera 2 to view clock 2. Record the moment light leaves at point A from camera 2’s clock and when it reaches clock 2 in the live video feed from camera 2. If you are only observing clock 2 from a live video feed and recording the time when the light reaches it, you would be eliminating the need for precise clock synchronization between clock 1 and clock 2.
@@av8077 To understand why ig I mean, if I as panicking on a way to save my loved one and the doctors outright told me it's impossible, that would not bring me any closure or explanation to the reason. So in the same way we ask why and we get the answer being impossibility, we aren't brought closure and explanation on a major physics study. Now wooosh me :)
Everything travels at the speed of light through spacetime so there is always that discrepancy, but it can NEVER change the result of an experiment. It also might not even make sense to ask the question in other words it may be a "confused question". I for one believe that it is a "confused question", but that still may be "just a convention".
My bank uses the same theory, but vice versa. When the money leaves my debit card, it goes really fast. When something is to be repaid, it takes much longer.
XD
Underrated comment lol
Oh, same here
It is, for bank, a convenient model to embrace. You'd be a banker, you'd do the same !
Now , of course, you don't believe Einstein really had any clue what was the speed of light.
The number just fell into his hat. Actually Morley and Michaelson were trying in 1887 to measure the speed of light. But the 'ether" screwed up everything.
Einstein just took M&M experiment result and declared that "ether" does not exist, and that froze everything in place including the speed of light.
LOL my bank is involved in this inverse of equities and is complicit as far as I'm concerned....I speak into existence and impose the maximum penalty for their impetulance with the application of the converse of consequence to the algorithms restricting my transactions and unleash the acholaids of irreverence to expand and proliferate the funds available to be unlimited everyday and to exponentially grow... please and thank you :)
This was a very fun present to unwrap. When you called me and told me to turn the camera on I knew something weird was going to happen and you certainly delivered. As long as I’ve known you Derek you’ve been destroying assumptions. Thank you for this friendship. It’s certainly enjoyable from my perspective.
Aaand subscribed
First
13 seconds ago
hey Dustin!
Use quantum entanglement
Great video. Despite getting a physics degree and teaching physics for years, I never came across this or thought about it. I was treating the video mostly as a 'fun to think about' sort of video, but your point at the end is really intriguing.
Even after watching the video, I have a few questions. What terrifies me the most about the questions, isn't that I think that they'll find a way to solve the one way speed of light; but the fact that if I am thinking about these questions, someone else likely has already, and there is a reason these questions don't answer it, and when I try thinking of the reasons, it makes the whole concept seem even more bizarre than it already is.
For instance, we are trying to measure the speed of light in a vacuum. But we could also measure the speed of light in a medium; intuitively there should be a relation between them. But the intuition must be wrong right? Or at least unverifiable. Which means even with an instantaneous vacuum speed of light one way, and a 0.5c vacuum speed of light the other way, there is some very strong asymmetrical physics going on when light goes through a medium.
Even if I have a medium that slows light down to a crawl, there has to be a reason it doesn't show the asymmetricity in the speed of light.
There also has to be a problem with colliding objects at relativistic speeds, due to the vastly changed special relativity formula. Two objects with the same insane kinetic energy relative to their stationary mass, can be travelling at two vastly different speeds depending on which direction they are traveling. One could be moving near instantaneously, while the other can be moving just below half c. Intuitively there must be some way you could use this information to solve the problem; but the intuition must be wrong, otherwise it wouldn't be an open ended problem.
Probably the reason things act so asymmetrically weird if the speed of light in a vacuum is asymmetric, is because that isn't "just the speed of light", it is the speed of causality. It means cause and effect acts different speeds in different directions; and there is no experiment you can do that can get past the limitations of cause and effect. All physics basically goes bonkers such that the asymmetrical speeds will always work out.
----------------------------------------------
Anyways, other than my mind breaking, I do agree that the end of the video is very intriguing. A solution to figuring out if the speed of causality is asymmetrical or not, could exist in a unifying theory. So the mind breaking isn't all for not.
Or perhaps the concept turns out to be pointless. As what does it mean if the speed of causality is different in two different directions? What is differences in time and space even mean if causality is different in two directions, aren't time and space dependent on causality. Perhaps the entire paradox of asymmetric speed of light is dependent on our own ignorantly rigid view of space and time? And thus unifying theory will have nothing to do with answering our fallacy of a question?
Ugh, my head. Anyways, I can always find solace in that Hexagons are the bestagons.
Hexagon = Bestagon
I made a separate comment, but no one replied so ...here it goes:
"I honestly have no idea what I am talking about, but ... can you use quantum entanglement to measure the speed of light somehow?
The entangled particles are "already synced", so "hit" the one "far away" with "something" that changes it's state and observe it/measure the time on the one "near" you... and do the same speed of light test from/in all "directions", then just compare the times to see if it's the same.
Only objection I could find to this not working is that I have no idea what breaks entanglement, so stuff like lasers, photons, whatever ... might not break it.
In rest, it seems like a good idea. Obviously I am wrong, or else it would of been tried by now, but I would really like an answer for this, if someone could educate me. Like I said I have no idea what I am talking about, so don't jump me. :)"
Okay, I have a question is the solution of 10:00 in multiple ways correct to verify de one-way speed of light okay hear me out.
1. If you do this and film both the clocks you can see which one turned on the fastest. Or which one is further. Once again you need to time it perfectly by turning on the cameras at the same time. But this one could be possible
2. If you move the middle clock to the left or the right you would get another result out of it if the speed of the light is different if not you have done it. To this correct you nee to set the clock on both sides at 300 meters away from the middle
I hope my English wasn’t that bad and that you understood my brain thoughts
Think one more time: "are distances AB and BA the same or they are measured in terms of light traveling time?" and you will get your sanity back. You can easily simulate the entire special relativity universe defining your (name A) causal boundary as now. It looks like "c0 towards you is \inf", and "c1 away from you is c/2" and for every BA synchronization event all time travel distances pointing to you are just zero, and still (c0 dt0)^2 = dr^2 = (c1 dt1)^2 the metric invariant your coordinates must obey.
This kind of "absolute" distance independent from your speed of light choice came from you actually postulated the object B being at the same location for AB and BA synchronization events but how can you define "the same point" within the experiment? Observer from Pluto will surely note your signals were sent and received at different points of space.
And here comes the answer: how can you measure any kind of "directional" speed of light if you can not provide the same distances in different directions?
I am an RF engineer. We use the two way speed of light to determine the wavelength of a radio wave. We use the wavelength to define the lengths of transmission lines to do things like impedance transformation. Although, these applications only involve the one way speed of light, the applications still function as if the one way speed of light were exactly the same as the two way speed of light.
Do the 3 way speed of light to get a rough estimate to prove that it dosen't travel instantly on some bend.
That's actually a proof itself. This video doesn't make much sense to me.
There was also synchronized pendulum that can be used to time clocks together as pendulums sync by mechanical energy
@@erlindar7410 The three way speed of light has the same problem as the one-way speed of light. How do you synchronize the clocks?
@@InsaneSibs The pendulums wouldn't be perfectly synced. The pendulums would always be slightly not synced up just because they transfer energy to each other at the speed of sound, way slower than the speed of light.
Should have wrote this in my physics exams, "It is neither a supposition, nor a hypothesis, but a stipulation that I can make of my own free will"
i still believe that 1 is prime
@@gasun1274 0 is odd
Definitely would have gotten your word count up
0 is positive
Lets be honest or make a bet... when the time comes, it will be proven that the speed of light is same for both directions, its pretty obvious. Right now "Veritasium" got the free hall pass for making wild assumptions since speed of light can't be measured with synced clocks.
My real takeaway is that two clocks, regardless of precision, will never be truly synchronized. This explains why I am frequently late.
@Steven Moore
Since I am the moving observer, it's my timepiece that runs slower. Only when traffic is unusually light can these relativistic effects be mitigated. It's just physics.
That’s what I told my boss for getting late at work, and I got fired...
Would like but your count fits into 8 bits exactly, don't wanna be the one to change that :)
*Edit* Damn someone changed it, oh well, added the like now it no longer fits into a perfect 0xFF
@@markm8188 ...but are you...or are you the observed standing still...
I think about that all the time, how two things can’t be happening at the same time, EXCEPT for two things touching each other.
Light: "My speed is immeasurable, and my time is ruined"
That's..... actually quite brilliant 😐
Underrated comment!
@@sinpi314 yes it is
Lmao 🤣😂🤣
You made me laugh so much 😂😂😂
WOW
The part where you talked about distant objects, since we see the same type of galaxies in their early life in all directions. That proves that if there is any difference, it would be extremely small.
Direction of light is the same - its moving towards you and not away.
I had the same thought, but it still has the same issue. Unless we're wrong about the big bang, it means any galaxies 13+ billion light years away started more or less at the same point as the matter that comprises us.
If the ancient galaxies off our north pole are instantly sending their light back to us, they've also been under severe time dilation as they've moved away from us for 13+ billion years, which means they've evolved far more slowly than the galaxies off our south pole. Our real time view of them shows them in their proto stages, which is exactly what we would see if the speed of light was the same in all directions.
There's just no way to avoid a two way trip and maintain any kind of certainty about simultaneity. Even if we assume the big bang didn't happen, everything is still moving away from us, which serves to counteract any lopsided c shenanigans.
@@foop145This answered my remaining questions about that scenario, thank you! Time dilation is such a wild concept to me I love it!
Also redshift being the same in all directions would be another "one way" measurement proving there is no preferred direction. A preferred direction would show up as one side of the sky redshifted more than the other. Redshift is an analog of travel time because it takes time for the space between the star and here to expand, causing the redshift.
@@ninehundreddollarluxuryyac5958this is the answer to this video. The redshift being basically homogeneous means light must travel the same from all directions.
I swear this channel is a gold mine for educational and entertaining content
Indeed
True
Very much so
Why are you watching this on the same day I am
@@hiruharii the comment man works in mysterious ways
I love how he called it right off the bat, “oh you’re talking relativity, you’re gonna something weird aren’t you?”
"You're gonna something weird"
This sentence makes me confused and or scared.
So is the speed of shadow the same as the speed of light?
Quay
@@Chadwicktrumpet No
@@Kristian-ql8zw but why is it not that speed. That is the question
I know for a fact that the speed of light depends on direction, because sometimes when I sit at a traffic light I can see the BMW driver behind me flashing before I see the light turning green.
I don't think the difference can be felt/measured through humanly senses. That bmw guy is flashing before it turns green.
@@yogi30303 that is the joke.
@@glinchdk yeah I guess among all the serious comments I took this seriously too.
@@yogi30303 r/swooosh
@@Majesticbro r/slamdunk
Light from distant stars is red shifted the same amount in all directions. If you are seeing light from one direction instantaneously, it wasn't travelling long enough to get red shifted at all because the space between us and the star would not have expanded at all in that (lack of) time. Even a small "preferred direction effect" would add redshift to one side of the sky and lessen it on the other. This is a one-way analog that allows comparison in all directions. You're welcome, I hope this puts your mind at ease on the topic. If you are still skeptical, explain why, because redshift requires time as far as I know.
I like the extra effort you put into the short acting parts to visualize the concepts.
Have a big clock display of a super accurate clock suspended on a roof or tower. Aim two cameras at this display. Let the clock run, its start time doesn.t matter. Have the first camera triggered instantly, the second camera triggered by a beam of light activated the same time as the first camera. Compare the photos to see yhe time difference. Depending on how powerful the camera, depends on how far away you could feasibly place the static clock and second camera
@@Raythe But how both cameras will activate in the same time?
@@Raythe but because the speed of light is different for different directions, two cameras will see differently delayed images so that the time difference you see in the images will be c.
I love when Destin is presented with something he genuinely didn't know/understand before. His face lights up with extreme excitement and intrigue.
That moment led me to evaluate my whole existence on whether I could share something interesting enough to impress Destin that much.
THAT is EXACTLY how scientists should reackt and be, and not make something a constant because they can't understand it.
"So someone has measured the speed of light...or have they?"
Huge Vsauce moment right there
They both never really were the same after the "Is anything Random?" collab.
Or were they?
*vibrophone intensifies*
what about quantum entangle ment to start the two clocks on both sides
@Windigo Jones that is why you watch flat earth videos lol
This is amazing, I already knew this problem, but no one has ever been able to explain it so well. Congratulations to the channel.😊
4:06 - "Or have they?"
I feel like this was a missed chance to put the vsauce theme on
Also noticed VSause referenceh
Here
th-cam.com/video/dQw4w9WgXcQ/w-d-xo.html
this is depressing here the right url th-cam.com/video/xuCO7-DLCaA/w-d-xo.html
Moon Men by Jake Chudnow
(Vsauce theme) - th-cam.com/video/TN25ghkfgQA/w-d-xo.html
th-cam.com/video/YgiyWGyJcIc/w-d-xo.html
This is the best explanation of "WHEN WILL THEN BE NOW?" I've ever seen.
Isnt it the best 'lack of explanation' of 'WHEN WILL THEN BE NOW'?
**i really like your point
Soon.
Get two clocks that are 100 meters away from each other. Start them at the same time. Shoot a light across from one clock to the other. When the light reaches the first clock it will stop. When the light reaches the second clock it will stop. You have 2 times and you subtract them to find one. And convert to the larger scale
@@jordanammons4851 How do you start them at the same time?
@@jordanammons4851 2:07
thanks for giving me another thought I can't talk to most people about cause they'll just say I'm crazy.
yeah xD also with the gravity video
They probably don't even have the intelligence to understand what you are telling them so it's easier for their little brains to consider you crazy than to accept that they are stupid.
Toooo true
This is just him wanting to think is so smart conjecturing that c is different one way than the other
@@r3kpwner303 Not true. People have different things to focus. No one has the capability to be smart in every thing.
Debunk this: There is no way to measure a people's intelligence.
As usual, a brilliant, thought provoking video. Thanks and I look forward to more.
I love that all these guys are friends and all they care about is figuring stuff out, learning and showing us.
They couldn’t care less about figuring stuff out. All of these stupid ideas are absolutely incorrect, and have been put to grave with actual experiments over 100 years ago
All they care about is showing their sponsors how many people watch their anti scientific horseshit
Go buy some kiwico and support the huckster
@Zach Comstock me and 11K other people who actually studied Physics
The rest of you should go buy kiwico
@@MarchelloMastrayani I'm actually interested in reading the experiment. Do you have any reference to papers that I could follow through?
@@MusicNewb absolutely, there were two brilliant scientists who set out to measure the difference of the speed of light in different directions over 100 years ago. Their names were Michelson and Morley and if you search “Michelson-Morley experiment” you will find many articles because what they have measured was an important stepping stone in the history of Physics
@@ENikolaev huh
Thank you for putting a camera on Destin when you had this conversation with him. I wanted to see his pondering/puzzled face so much! 😁😁😁
We* wanted
When a physicist comes to an engineer with a question: "OH you're gonna do something weird arent ya?"
+Science Revolution I see but the whole religion thing is better than science is defunct
Thing this deep makes me question the existence of this very video. Really.
@Science Revolution , You list SO many things which are not true here that I won't bother to point them out. You might as well be traveling instantaneously.
@Science Revolution If you write an article and prove that mathematically, you could actually become a reputed scientist. Go ahead and do that. That's the beauty of science, all scientist have that in their minds, a sentence that says: "we could be wrong, and we probably are". We have like 3 centuries of science and look around you, look what they've already done! 300 hundred years is nothing compared to the time that our species is in the planet and absolutely nothing compared to the age of Earth itself. Stop comparing Science to Religions, they have nothing to do with each other.
Guys don't reply to that revolution guy,he/she literally mass spams this exact paragraph on all science related channel nowadays along with bunch of his flat earther friends,
Well he's/she's literally questioning the very science which is allowing him/her to watch this video on his/her device, it's like if Elon Musk's son starts saying neuralink is fake.
I was watching a video where a psychiatrist explains why these kinda people exists who claim the earth that it's flat or all the theories are bs , it's like they want to feel special as if they possess a knowledge which is hidden from the general public,it's like the film 2012 where only few people knew about what will happen actually in the start ,these want to get a feeling like that forgetting the difference between real life and Christopher Nolan's fiction scriptures , however this is also a state of mental illness which must be treated and not like back in 1700s when if someone started seeing ghosts , people started excorism or drowned him/her in the water lol
Happy Birthday, Derek! You are a beacon of light in this dark, dark world.
"so someone has measured the speed of light... or have they?" Hey, Vsauce... Michael here
Hahaha exactly!
You look like vsauce but mexican
Lol
xD
VSalsa
He said "or have they?" I was kinda sad no vsauce music played
yea
If the pulse to start the second clock us traveling at the speed of light(2:27), then why can't you just subtract the number of seconds the second clock has been running for from the first? I feel like this is a stupid question and I'm missing something...
I know, right?! At 4:05 I thought I was watching a Vsauce video. lol
@@mahirshyam4127 because if the speed of light is potentially different in both directions, then how could they know how much to subtract it by?
The experiment would be trying to measure the speed of light, but you’d need to know the speed of light in order to know how much to subtract the second clock by.
For example, imagine trying to solve for the length of the hypotenuse of a right triangle, but the only information you’re given is the length of the bottom leg.
Asking why you can’t just subtract the speed of light from the clocks to get the answer would be kind of like saying “why not use the length of the bottom leg and *the length of the hypotenuse* to find the other leg? Then from there, just use this other leg to find *the length of the hypotenuse.”*
Hopefully this example makes sense, I’m not the best at explaining things.
yeahhhh
"We've invented an FTL drive but you can only turn left."
Lol
If you turn right you go backwards.
It's not an ambi-turner!
Douglas Adams Likes this comment!!!
NASCAR is going to have to build bigger tracks...
I think a lot of people will watch this and have the attitude of "well of course it's the same in every direction, why wouldn't it be?" which I lean towards. But the point at the end is the most important part. The fact we can't measure the one-way speed of light is itself a huge clue (possibly) about how the universe works that is staring us in the face.
That’s why going to work feels like a drag and coming home feels quick.
Lol
Hahaha
I know this is a witty joke but there's a video about this kinda time where u feel vs time that is real in vsauce
The answer is easy, if u wanna measure the time delay in one direction, u send an impulse between this two clock's in each of this two directions and u will see if one starts later ....
Quick maths
@@babylebron6119 I'll take it you didnt watch the whole video when you wrote this. He explains that the problem is that it remains unknown if light travels the same speed in all directions.
"Speed of light is the universe's refresh rate." -Stephan Wolfram
Has that got to do with his physics project?
speed = distance/time
refresh rate = 1/time
YES LOL
I haven’t got to the end yet but can you use some kind of quantum entanglement trigger in the future.
Are we living in a simulator?😢
I am an engineer and was working on time synchronization between two devices on the same network. We encountered cases where network delay from A to B is higher than from B to A and such cases resulted in inaccurate synchronization. I was working on solving this problem and after watching your video I realized it’s essentially the same concept- sending signals from earth to mars is like sending network packets from A to B. So the conclusion was, without the help of any external device it’s impossible to accurately sync time! Thanks a lot for your video :))
How does this affect the light year as a measure of distance. everyone is fascinated by it as it, because the observations of the star Betelgeuse for example, suggest that it is ready to explode into a supernova, but what we are observing occurred 600+ years ago?? I've also seen deep space observations of a binary star system when one of the stars occults it's twin for over 10 minutes, which blocked the light completely, it wasn't picked up by the sensors.. but as they eventually moved and came back to view, it was instant... i think that was 1000's of light years from earth, so why was it instantly seen and formed the same histogram reading it was prior to the occultation. I'm no expert it has all fascinated me since i was a kid, so if you have any ideas, or let me know if ive got this all wrong.
We dont need a clock at all.
We shine a laser moving at the receiver at a speed of 100 km/ h and observe a Doppler shift in blue. We do the same thing from the opposite side, we observe exactly the same displacement. Congratulations! The speed of light is the same in both directions :))) Easy.
@@rainmansound1 you need clocks to measure the speed of 100km/h. And if the speed of light is different in different directions, your measured speed of 100km/h will also be “actually” different
But we can synchronize clocks across vast distances (this is the whole reason GPS works, every clock in the GPS network is Synchronized because they know their exact position and relative velocity to other satellites, thus they can adjust their internal clocks to negate time dilation... because they have synchronized time, their beams to GPS devices with their exact time stamps, allows the GPS device to exactly calculate how long it took for that beam to reach the device from the orbiting satellite and thus we have very high precision triangulation of location... all because these satellites have synchronized time.... The thing Veratsirum is blatantly ignoring is that the reason two clocks "can't" be trusted is because relative to each other, their individual velocities results in time dilation, but this time dilation can be compensated for because we have the equations for general relativity(how we can synchronize GPS)... What he's saying is a barrier to recording the speed of light in one direction, is actually proof that the speed of light is the same in all directions and not just a convention.... TIME DIALATION.... even if the speed of light in one direction is slower than the speed of light in another.... Special Relativity tells us that Time Dialation kicks in... This will expand and contract space time in either direction, so that the resulting measurement (Distance of time) will always = C... this will happen by either contracting space, or elongating time, but the result will always come out at C (and is proven experimentally, as well as the basis of much of our technology for space travel, GPS, and quantum sciences)....
That a crazy good example! Network delays could definitely be different in each direction.
When you remember that time and space are actually linked in spacetime, it's rather unsurprising that it is hard to align / synchronize time when spacial distance is large.
The concepts of simultaneity and spacial proximity are the same thing in spacetime.
Further, I don't think that photons actually fly through space for a specific amount of time "until" they reach us. The existance of photons is only ever relevant when we interact with them. In a way, the "observed" photons/light are the interaction between an atom of a far star and an atom in the retina. This interaction could be computed by the "universe engine" in the same "time"step /instantly.
after years of religiously watching you when i was in high school, and as i am now about to finish a computer engineering degree, i would like to thank you for rekindling my passion for physics and understanding the observable universe
Congrats man
Aye congrats! Just finished my first year of computer engineering. Did you choose to go into hardware or software?
i think derek is wrong becasue light reflects back in mars so mars lights speed conventional.
@@OasisMilo thank you!!!
@@muazshash9802 thank you!! well my major is supposed to be a combination of both, so i took a lot of electronics courses which i ended up absolutely hating lol. so i'm focusing more on personal development for the software side. wish i could take more CS courses strictly but i gotta finish my requirements. what about you?
Lol when Destin realizes Derek is about to drag him into relativity
yeah, that was hilarious.
That got me good when he realized what was about to come up XD
When we look at the stars, we look back in time (at least if c is isotropically constant as usually assumed). The furthest look we can have is to observe the microwave background, isn't it? And as it changes smoothly the speed of light should change continously depending on the direction. Moreover, if we assume c is infinite for a particular direction, we should therefore be able to see indefinetly far into the universe and thus indefinelty much galaxies. So, if we compare the galaxies visible in different regions of the sky, we should be able to estimate an upper limit for deviations from an isotropically constant speed of light?
Came to the comment-section just to point this out as well.
This exactly, an interesting video nonetheless but this was not mentioned
they had that tired photon theory
Arguably, the distance of those far away galaxies cannot be determined if C is not constant. So basing the value of C on how much more "primitive" a galaxy looks depending on how far away it is only reinforces the unknown presented in the video. If we look at different patches of the sky we see that there is no standard/constant change in the development of those galaxies, and this is generally explained as the result of gravitational lensing. However, the same observation can be explained by the variability of C as well.
I was just wondering the same thing. If direction matters, wouldn't we see parts of the sky more or less as what they were some time ago (and therefore having dark gaps in which light hasn't reached us yet) and at the same time other parts that are much much brighter since that direction is the "realtime view" (if we can call it that) and we see much much farther away (and more stuff too)? Anyway, cool video as usual :)
I always love these types of videos, they always show just how little we actually know about the universe we all live in!
"Stars look exactly as they are right this instant." Gave goosebumps.
th-cam.com/video/nRGCZh5A8T4/w-d-xo.html
We saw past of star coz it take millions of year to reach star's light to earth
@@ABHEEeeee Watch the video
@@ABHEEeeee how do you know? Are you saying you can prove the return trip isn't instantaneous?
Have a rocket exactly half way between earth and Mars. The ship will send one message to earth and the other the Mars and then instantly back to earth. You would expect that the message that was sent to Mars first would take exactly three times as long to reach earth as the one sent straight there. If this does happen then the speed of light is the same in both directions.#big🧠
The moment when Destin realized "Oh snap, Derek is going relativity• is Golden!
Where does the quotation end?
What relativity actually tells us about is that it is meaningless to even talk about "right now" for other observers, time is trully relative.
Synchronisation problem only reminds it for those in doubt
Basically, the problem is the invention of language and our definition of "Now" lol, the math works, words dont
but is relativity a constant or relative to itself?
This. People would understand relativity much better if they were introduced to concept of locality earlier. There is only one real "now", which is _my_ now.
@Science Revolution your spam will be reported
@@dan7291able yes, this 👌
Language is older than maths/logic and physics
Here's an experiment that I don't know has ever been tried. Set up 3 points on a line A,B, and C have them be equally spaced apart. Using the speed of light from the round trip measurement we synchronize the clocks at B and C from A that way we know that the synchronization signal only traveled in one direction to both clocks. Then measure the speed of light between B and C in each direction separately.
You wont know long it takes for the light beam to travel from A to B (and equivalently B to C) and therefore cant synchronize them
Dude! Your cinematography is killer! The shots of you on top of that hill with the Belt of Venus visible in the sky was positively cinematic!
If using not 2 timers, but 3 timers. Possible to get real speed)))
This was the most elaborate, philosophical, mind-boggling, brain bending, insightful, confusing way of saying: We Can’t.
"So some one has measured speed of light"
"Or have they??"
*Vsause theme plays*
I kinda expect there's a theme song... But left disappointed
*vibrophone intensifies*
Is he even alive
Vsauce must have run out of topics. Loved his channel.
yes what a garbage clickbait channel this has become....
Someone said , "There is no time, only clocks and none of them agree". Thanks, I always enjoy this channel!
This is one of the things that I love about physics. As a quote from my teacher “nothing can ever be proved there can always be some thing that is impossible for us to measure. This is what makes physics and all other things related to it able to revision”. There could be thousands of things that are impossible for us to prove because our brains could not possibly comprehend it and our technology, currently, could not feasibly measure it.
When I learned that under any circumstances, some form of energy will always go to waste. Since high school, I have always done imaginations on how we can build a device where 100% energy can be used. Like creating a light bulb that emits heat but using that that heat to power another device. But then I thought I don't need all the light that the bulb is producing. So yeah my mind always boggles in these imaginations. But it's fun to invent different devices in my Brain nobody will ever know.
There is a logical answer to this dilemna ... Reflected light is still light, therefore it travels at the same speed because it is the same... Thing which is nothing more nothing less it is just "LIGHT"
KISS keep it simple stupid.
But isn't the speed of light constant? The entire basis of C is that it is unchanging. If you measure it in one direction, well... you've measured it in all directions. It can't change.... unless all of that is wrong and C does indeed change. If it's not a constant, well, that breaks a lot of equations, doesn't it?
@@deydraniadiancecht8298 That's the point of the video. That it is the definition, not the fact. And that it breaks none of the current laws of physics as long as the average is 'c'.
If light is Infinitely fast on the way back wouldn't we see reflections of light from far away galaxies and there would be no observable universe barrier?
“We don’t you reply quicker?”
“Sorry babe I’m at Mars rn”
That's the way to measure the one-way speed of light. Send babe to Mars.
@@majidaskari8306 it doesn't matter; no matter if light is same or different in all directions, it will take 20 mins.
"Or have they?"
**strong flashback of Vsauce*
Why didn't he queue the song?! haha
@@KingR787 He'd need a colab and permission to use the song =)
It's a shame Vsauce doesn't really do these types of videos anymore
Us to aliens: "We measure a meter as the distance a light takes to travel in 1/299 792 458 seconds"
Aliens: "Which way monkeys?"
Ok
Use a ultrasonic wave in the middle to activate the 2 clocks. We know sound travels the same speed in both ways. Measure the distance of the 2 clocks based on the speed of sound and use this as the activation time for both clocks.
Then shoot the beam of light.
I have a kind of similar idea, but don't know where to verify???
I would guess that either time dilation or length contraction will cause the signals to arrive at slightly different times no matter how precise you are.
“No Officer. I was not speeding. You see, the speed of light different depending on the direction.”
Officer:
“lol. Here’s your ticket.”
Actually this argument has held up in court. Google it, it’s pretty awesome.
@@epicvillain8308 I tried to but couldn't find it. Mind sharing?
@@epicvillain8308 you are lying
@@lilsabin 🤣
@@epicvillain8308 No but the dopler effect has, even though it works in the driver's favor. Far as I know this argument does not work anymore because of that factor (I just drive a truck though 😅).
4:07 *Vsauce music starts* and im anticipating a round head will pop from the bottom of the screen.
Hey, just to let you know someone else in this comment section named Nihab Khan copied your exact comment word for word soon after you posted. Control + F to find the bastard. Go give him hell lmao.
I’m glad someone else thought this😂
IKR
Or is it,,😂😂
yeah my brain stopped working.
I long for the days of before I saw this video
"Ok, let's synchronize our watches!" - 2070 Nobel Prize winner
SEND THE REINFORCEMENTS THIS GUY IS LOW ON LIKES
Also there were two nobel prizes awarded for breaking the assumption scientists had about the charge parity and time simmetries so this wouldn't be a first but would probably be one of the best
You could just move both clocks at the same speed for half a mile then measure the exact time the light was turned on, and then the exact time it reached the destination and do the math
i meant move them In opposite directions
I thought this said witches... Happy Halloween!
I got a ideas:
2: get a câmera, a lazer, 2 servo,a rod or a beam, and a timer.
Set everything on top of a servo to rotate a little bit every Second and the other servo to counter-rotate the earth's day night cycle, place the Rod(or beam) in the servo and the lazer pointing (not in the Y Axis (up and down))) in the center of the contraption and the câmera on the other side pointing to the lazer but a little offset to the side (só the lazer dont hit It).
Program the lazer or the câmera to shoot at a time while It rotates. You can place some flags around tô see the derections, but the places where You cant see the lazer You Will know where the light is faster
I absolutely love when people can take something ordinary and make us step back and see how much we don't actually know! Even if you can't confirm or prove the knew idea. The greatest discoveries are made when people are willing to challenge the status quo. Thanks for another amazing video
Measuring the speed of light doesn't seem ordinary to me even if it's the same in all directions.
Actually they (in error) took something pretty simple and made it unnecessarily complicated. The solution: Now that we have measured the two way speed of light, we can measure it one way. An observer on Mars can be told that precisely at Noon their local time, that Earth will send a communication. Precisely at that Mars Noon (which Earth also knows on its own clock's time from a previous two-way measurement to synchronize the clocks). Earth sends the communication. Mars then records when the communication arrives and compares the speed indicated to the assumed speed of light (based on the existing two way precedent of nearly 300m M/s). This tells Mars exactly how long it took the light to arrive - and whether it matched the assumed speed of light or took longer or took less time to reach Mars. And if we furthermore allow the communication to reflect back to Earth, Earth can use the same method to record that signal's speed back to Earth and show whether it matches the traditional assumption. To verify this, all Mars needs to do is confirm later for Earth observers at exactly what time the reflection on Mars occurred. This allows us to verify the speeds each way individually and whether light was slower or faster in either direction.
This channel is awesome. It digs into fundamental issues in physics - verging on philosophy (ontology and epistemology) - within five minutes of the start of the video you’re right in the trench. But you’ve never been left behind, the issues raised are never inaccessible. Supremely good work.
So what does they mean when they say it takes 8.2 minute for sun light to reach eart pls can someone explain
Rich Simpson: A very very good observation.
@@Sharmajay69 We know the speed of light in a vacuum to a specific approximation, and we know the average distance from the sun to the earth. So we can say that light leaving the surface of the sun reaches the earth in about 8 minutes.
This video is about how our measurement of this speed can never be exact because it’s physically impossible to set up such a measurement. But we can work it out approximately. I did it at school using a 100m electrical cable haha
@@rumlia haha thank you fellow youtubonaut
@@jam-trousers i mean light travel in one direction in vaccum and we know the distance and time to reach the earth. So we can measure speed of light in one direction. But versatium is saying its not possible.
Can you pls explain me in simple layman's term. I am novice
Thanks in advance brother
Found this on @Brian Koberlein's blog:
"Then in 2010 Jason Lisle revived the idea of anisotropic light. If light moving toward us travelled at infinite speed, and away from us at half the traditional speed of light, then it would allow the most distant light in the young universe to reach us while still agreeing with relativity.
As crazy as that might sound, Lisle is right in claiming that such an effect would be indistinguishable from relativity, and this has made the work popular with young Earth supporters. However agreement with relativity isn’t enough. If light did actually reach us from distant galaxies instantly, we would expect galaxies at all distances (or more formally redshifts) to all look the same age. In fact, what we see is that more distant galaxies are younger than closer ones. If Lisle’s idea was correct, we wouldn’t see the magnification of distant galaxies due to cosmic expansion, nor fluctuations in a cosmic background, nor galaxy clustering in agreement with dark energy, nor a host of other observational results."
This is exactly what I was thinking. I'm curious if Derek has an explanation as to why we still observe distant galaxies the same way in every direction if lightspeed would vary based on direction?
The notion of instantaneous light speed breaks all of physics, unlike as is reported in this video. SR and maybe even GR would remain the same, but QM would explode instantaneously. You have to realize c is better understood as the rate of causality, not just the upper limit for relative object motion, let alone the ‘speed of light’. Much more likely then, if an asymmetry exists, it is a very subtle one, otherwise you’d run into CPT violations, and also have to extinguish the conservation of linear momentum - which itself predicates all other conservations.
It's travelling one way to us though isn't it?
@@joshandromidas The thing is, that if lightspeed fluctuates depending on which direction it travels, we'll still see different age of galaxies, because of the difference in speed, so it'll look the same as if lightspeed is constant.
So wouldn't your comment then prove that there is no direction in which light moves instantaneously? Also, considering the uniformity of the cosmic microwave background, wouldn't that show that the speed of light is indeed isotropic? Any directionality of the speed of light would then show in the CMB, right?
You can synchronize 3 clocks, put two of them at point A and one at point B; let the first one turn off as the light leaves it to point B, the second one turns off as the light reaches it from A (connected with a light sensor), and the last one turns off as the light reaches it from B (also connected with light sensor)
Even if we figured out the exact speed of light and KNEW what it was, it doesn’t change the fact that I have to go to work tomorrow
and that's facts
the speed of work is always c
@@rsolsjo unless it's Monday. On Monday it is C/2
@@michaeldivens7570 bruh in a maths lecture its c/5
When's the lay off?
"To measure the one-way speed of light, we have to know it" has a ring of Gödel to it - a self-referential truth that can never be proven within the system. Keeps me up at night...
i think self reference contributed to many unsolvable things we have currently. turns out
we need to start to look more into ourselves to know everything out there
“So someone has measured the speed of light......or HAVE they?”
*Vsauce intro starts
I heard that music start...
Im your 69th like
Agreed - thought this felt like a Vsauce video the whole time.
It is easy - set 2 sensors that send pulse when light passes thru them to perpendicular single clock, so there is no need for synchronization. Path from each sensor to clock and path direction should be same, so delay betwedn pulses will express exzctly time that took light to travel from first sensor to second - that's it, you will measure one direction light speed. Can make a such measurment in several dirdctions just to verify that result is same
you don't need to know when exactly they send it - you just need to measure delay between 2 pulses. Since each sensor sends its pulse in same direction for same distance , so time of travel of each pulse to clock will be same and delay measured by clock will express exactly time that took light to travel from sensor to sensor
E=mc2. E and m are scalar quantities and have no direction. Basically, general relativity won't work if c is anisotropic.
Well, c has a defined value, so the formula will allways be correct. The video is about measuring the speed of light in one direction. C is just dividing by 2 the time used by a ray of light going from here to there and returning here. So if from here to there light travels at 2c and from there to here at 1/2 of c, the average is.. c
"Or have they?" --- Thanks VeritasiumSauce.
Destin was probably having a perfectly fine, normal day and then the phone rings. Now he has a broken brain.
Have a rocket exactly half way between earth and Mars. The ship will send one message to earth and the other the Mars and then instantly back to earth. You would expect that the message that was sent to Mars first would take exactly three times as long to reach earth as the one sent straight there. If this does happen then the speed of light is the same in both directions.#big🧠
@@jontisaurusrex9851 In order to measure that, the clocks on the ship and on earth would have to be perfectly synchronized. How are you going to do that?
And that makes it an even better day.
@@Anton-cv2ti Maybe one way would be to accurately calculate at what time exactly the ship would be in a specific place between mars and earth and when the ship knows it's in the correct spot, just set the time to the predetermined on earth time, then proceed with the experiment suggested above.
Rotate a tube or a some type of gear with slits on opposite sides and have a detector to see if light made it through. At a certain velocity of rotation light won't be able to traverse it. That speed and however large the slit is (the distance it would need to rotate to stop the light from making it through) gives you the time. Use that time and distance between the slits to get the speed of light
I spent a year putting this episode on hold without realizing how important the concept is. Time to wrestle with this concept now.
I NEED MORE VERTIASIUM IN MY BODY!!
i was stumpped by this video at first for a long time. thinking there was a dire need to confirm lights single direction speed. but i don't think there's any need to do that, I've realized this video is misleading. there are tons of examples in physics that confirm the speed of light is the same in all directions, DESPITE not being able to measure it as of yet.
the most notable being if the speed of light were different from different directions, black holes would represent that, as the event horizon would elongate toward one direction and be flatter in the other. making cone-like, egg-like, or junior mint like (a dimple on one side and a crest on the exact opposite side of the dimple) shape pointing to the fastest direction light can travel, because it would take more energy to suck in light in from that direction. instead we observe the event horizon to be perfectly spherical confirming light travels in all directions and polarizations with the same amount of energy and mass.
@@Ae3lolz but the deformation could be unmeasurable from Earth. The video just shows the most extreme example.
@@m.j.v.4463 nah its spherical. theres proof and pictures, recent ones
@@Ae3lolz I don't believe that is correct. Link?
Misleading? Everything he said is true, you can't measure it , sheesh.
What are the tons(misleading?) Other examples out there?
All these factors suggest that time is the determinant of the speed of light, and it is well-known that time moves in one direction. Consequently, the direction of time is directly proportional to the speed of light. As such, light should travel faster when following the direction of time and slower when moving in the opposite direction or making an angle greater than 0 degree.
Me a smol brain: light travels at 1 lightyear per year.
edit: turns out, this aint smol brain; this is big brain
r/3likecomment
Jk you don’t get a subreddit
@@LargestLuke 😀😭
in fact that smaller size of brain is the faster neuron work on brain Wich make it more smarter
@Waldel Martell even if it small it has 1 Petabyte or 1 million Gigabyte of room
One thing we can know: Click-bait travels at superluminal speeds.
Why is Donald Trump pretty and I am not? But why does he only have a wife but I have TWO HOT GIRLFRIENDS who I show off in my masterpiece YT videos? Do you know the answer, dear pat
True
someone's about to get reported
To quote or at least paraphrase the late great Douglas Adams: Nothing travels faster than light - except for bad news, spacecraft powered by this technology were rather unpopular when they arrived at their destination.
@@freds2150 I did report him. This dude keeps on spamming on a lot of channels, probably hired a program to it.
Okay, I've got a few reactions to this:
1. I feel like Michelson-Morley should have been brought up at some point. I want to say, "But didn't the Michelson-Morley experiment disprove the existence of a preferential direction for the speed of light?" but I'm guessing either something about the measured directions being orthogonal rather than parallel or something about the fact that both directions were using round-trip light would destroy that notion.
2. How do you explain something like the CMB if the difference in the one-way speed of light is as extreme as c/2 and instantaneous? Wouldn't that mean that one end of the Universe was extremely hot and dense 26 billion years ago and the other end is identically hot and dense right now? How does that make sense?
3. Could we measure the one-way speed of light if we could make use of some egregiously curved spacetime? Like, measuring light orbiting in the photon shphere of a black hole, or if we could manage to create the 3D equivalent of a torus (I suspect that might require exotic matter, though)?
I asked myself the same thing. Similar to your question 3: Imagine a supernova in a galaxy far away. Now imagine a black hole between us and the supernova. We will observe the light twice: Once on the left and once on the right side since the light will be bent by the black hole due to gravitational lensing. Now if light was traveling faster in one direction of space, shouldn't we see a delay between the light on the left and the right side?
Regarding the second point
This is something that bothered me as well. I'm pretty sure that can be ruled out if we remember that The Observable Universe is bound to speed of light and where the speed of light is infinite the whole infinite universe would equal The Observable Universe.
And that's why it looks that hot and dense? Does that make sense??
@@matthiaskuhr8417 yes, you would see it twice with a delay. We are currently observing a star the went supernova on the other side of a black hole and so far 4 images of it have appeared and they were able to predict the week the next one would show up.
@@matthiaskuhr8417 draw the diagram. The light bends one way and then bends back to reach you; on the opposite side of the black hole, it bends in the second direction first, and then back in the first direction. You’re measuring the two way speed again.
Thank you. I was asking 1 and 3 myself.
If you think speed of light is different for two directions, it’s your job to prove it. Not just telling people to prove the speed of light is the same. You raise a hypothesis, you prove it. So what if I say there is a ghost standing right next to you, and tell you to prove me I’m wrong otherwise the ghost is true ?
So you propose the speed is the same both directions? it's on you to prove it now 🤷♂️
No that was albert einstein my guy, who tf are you?
Notice how he says the debate has been going on since 1905 and the video is 19:05 long...
Coincidence? No!
Coincidence?? Yeah coincidence
100% not intended, it takes people with no time to think like this
19:04
I stopped watching it after 13min, coincidence?
This video really changed the way I look at “simultaneously”
haven’t seen the video yet, but based off psychedelic experience i know exactly what you mean
@@vast5853 could you explain ?
Simultaneity*
Now when i do simultaneous equations, i do the calculation for one, and i instantly get the other one.
This is an awesome, very thought inducing video. A follow up video on what could be causing this potential asymmetry would be fascinating as well. However the centered clock synchronizer at 9:50 doesn't exactly equate to the GPS example he introduces next because in the first example, the A/B clocks agree (correctly) that they are stationary relative to the other. In GPS, the clocks are in relative motion. This creates a larger problem when trying to keep the satellite clocks running at the same "rate" as the ground clocks. They in fact have to run at the same ongoing rate for the system to function accurately but this (like it or not) is in contradiction with special relativity. I cover this in my twin paradox video.
this video made me feel insanely smart for 19 minutes and 5 seconds.
True 😂
Um this made me feel insanely stupid for 19 minutes and 5 seconds...😂
Dunning-Kruger Effect?🤔😁
Imagine watching it high
same man wtf*
So here is an idea. Two mountaintops. On one you make a light blink. On the second one, where you are, you place another light and you synchronize the blinking. So now, they are blinking exactly the same. Now take a hike to the other mountaintop. The lights won't blink exactly the same. Measure the time difference, measure the distance. Calculate the speed. Do this in a few different directions and compare the outcomes. Voila. Happy to help.
So someone has measured the speed of light.
Or have they?
**Vsauce Music intensifies*
What is light? This feather is light.
Feathers are used by birds to fly.
*Flips you the bird* But what about this bird?
Why is this called "the bird"?
@@MatthewHughes811 accurate
Hey guys Micheal here
Thief
@@MatthewHughes811 lol this is gold hahaha
The worst part about me watching this video, is that I understand everything he says, but at the same time, I understand nothing.
Dude is too smart
@@abrahamsanchez7455 indeed
Understand the words, but not the meaning, it's what happens
He does speak English pretty well
Same here...
This certainly has interesting legal implications for speeding tickets based on laser detectors (previously mistakenly referred to as "radar guns".)
I'll try to explain this to the cop the next time I get pulled over. I might get a ride down to the station instead of a ticket.
Apparently it doesn't. Lol
@@Future__martian Fair point. I made a poor choice of words. I was referring to laser-based detectors. In addition to radar, police commonly use laser guns as well. These are completely different than radar guns. They function differently from the police officer’s standpoint, they have a number of advantages and limitations compared to radar, and they require completely different tools to combat as a driver. Thank you for point that out.
@@Future__martian soooo, you are saying radar waves are as slow moving as sound?
There's 2 types of devices used by police to determine a car's speed. Radar measures the doppler shift in the signal and uses the shift to determine the speed of the vehicule.
Laser ones, fire a laser at your car and it bounces back and then it does it again and measures the difference between both interval. So it's measuring the 2 way speed (going to and coming back) and not single way. So even if light was slower in one direction it wouldn't change the final result.
Here’s a way to, if not disprove it, make it demonstrably less likely: Interstellar astronomy. It’s a one-way trip for the photons in all directions towards Earth. If c was meaningfully different in different directions, we would expect to see a very distinct difference in what we see from each side of the sidereal universe. One side would appear substantially younger to us than the other, in terms of types of stars and galaxies we’d see. One side would also be substantially denser with visible objects, because the Observable Universe would be longer in that direction. Which to my understanding is not what we see at all.
That only rules out a really significant difference, but it’s a start.
4:18 “then that sounds like a veritasium video”. Love that destin didn’t entertain this sophistry lmao.
"so someone has measured the speed of light... or have they"
Vsauce right there caught in 4k stealing Derek's skin
*Vsauce was an imposter*
0 imposter remains
*vsauce music starts*
4:06 "... or have they?"
VSAUCE enters the chat
*Vsauce music starts*
I’d love to hear thoughts on my hypothetical here:
If you were to take a circular object of a known circumference, then wind a specific length of fibre optic cable around this object, send a pulse of light at the same time as beginning a clock, with the clock being at the same location on the object as the laser pulsing the light. Using this, you would be able to average the speed of light based on the direction the circular object is parallel to. If you were to then rotate the circular object about the Z-axis to an angle that is different than the absolute value of the starting angle, then measure again, you would be able to conclude whether or not the speed of light is the same in a given direction.
Mark the Astronaut sends a message.
Me, on mission control: "Oh hi, Mark..."
You're tearing me apart, expansion of the universe!
"So, how's your research life?"
ha ha ha what a story Mark.
"someone has measured the speed of light....
...or have they?"
Don't you VSauce us like that
Hahaha exactly! I expected Michael to pop up out of nowhere
@Florentin sound happens because of pressure waves, which happen because of the fluid (air?) Moving, which is made of various particles, that interact with each other by means of electrical forces. And those are linked to electrical fields, which propagate.. at the speed of light... 🙈 Therefore I guess it's checkmate again
Brow if they send massage to Mars at 12:00 and send another massage to Mars after 20 earth minutes. So the man in the Mars kan take the first massage at 12:10 and he can take time and he can se how long it will take to get the other massage so he can find the light speed.
It is to easy.
Believe me
@@tthozan7632 Stop spamming this.
Veritasium basically is VSauce nowadays
That was actually one of the best things I’ve ever seen on TH-cam. Excellent work!
I see no reason to use the word “actually” here.
@@kevoramma great point! Thank you for using TH-cam comments to help correct my grammar to be more in line with your taste. Tell you what, give me your email address and I’ll send over some other comments I want to write and you can give me some more feedback before I post them 👍🏻
@@tylerm.9408this is one of the best comments I've seen
@@tylerm.9408 lol
@@SquidKiller-oi3bb but is it ACTUALLY one of the best comments you’ve ever seen?? 😂😂😂
Without reading all of the comments. My suggestion is to use 2 lasers and time each direction. separately.Not being a Smarter Every Day or a Veritasium, I am however an Every Day a Verispasium. Obviously this has already been thought of. The 2 of you play off one another very well, it's a pleasure watching both of you.
We can't time any direction independently. We can only time two directions at once.
"so someone has measured the speed of light? or have they " sounds like vsauce
Veritasium, Derek here...
*Vsauce music starts playing..*
**Camera zooms to michael**
Rip vsauce
@@debo325 is michael dead????
Old Derek: makes people on the street feel stupid
Present Derek: make rocket scientists feel stupid
True
only by asking a dumb philosophical question that reality refutes on every level... This is why philosophy is garbage. Possabilities dont matter, reasonable probabilities do.
@@terryfuldsgaming7995 bro my mans said Einstein himself did the two way measurements and he has many points in this video based on relativity not philosophy
Past derek and present derek is meaningless according to this video
@@terryfuldsgaming7995 Reasonable? Take a good, hard look at our current understanding of physics and come back when you're ready to call it reasonable. The very reason philosophy _is_ interesting is precisely because there are possibilities about reality that sound completely bonkers to us, and yet there's strictly nothing explicitely fordidding those possibilities... so what rational reason could you possibly have to dismiss them entirely? Symmetry? That sounds like a good argument, but there are plenty of situations in the real world where symmetries are broken. You could say that, on a purely a priori basis, more symmetrical options are more likely, but because it's a continuum between being completely symmetrical and being completely asymmetrical, without changing anything about causality, physics or your everyday experience (since if there was a difference you could measure it), the probability that the situation is _perfectly_ symmetrical would be zero. Even as a thought experiment, this entire thing is fascinating because it completely breaks our intuitions.
Don't you just love it how Destin was spelling out how they measured that ball's speed and immediately realized what you were up to? 😸
Can't help but love that guy
"... and then your clock...... goddamn..."
How about trying a game of mirrors? Place the clock and the mirror at distance X and measure. Then, add another mirror, where the first reflects to the second and then to the clock, keeping the same initial distance X between them. In the end, you can subtract 2 paths from the first test from the 3 paths of the second test. Leaving only one part remaining.
4:04 "So someone have measured time... or have they?"
You're making me feel like you're actually Vsauce's cousin
Anything to churn out another vid, my friend, just anything......
..or is he?
Hey Veritasium, Derek here
@Alexis Degryse If the light from the nuke has reached us then it already happened an hour ago.
(Not sure what you mean by an ‘hour behind’)
My head is hurting but I'm enjoying this video not gonna lie. Things that's just unknowable is really interesting to think about.
But he answered the question himself... around 13min he explains how it is possible to measure if the speed of light goes faster one way than the other...
Correction: another way to measure it in around minute 15
14:01 actually explains why it's unknowable since all the possibilities can actually be possible. Light could move at the same speed in all directions and light could move a certain speed in one direction and almost instant coming back.
There's no way to prove which is correct hence it's called a convention.
Meaning everyone just agrees that light moves in a certain speed equally in all directions to make things easier.
@@kelvinnueveanimeguitar1983 To be honest it almost broke my brain too but I'm happy to say I finally solved the light measurement puzzle and posted a video on it.
Doesn't he solve the problem with the mars example? When we travel to mars that experiment can be done. The clocks and be reunited on earth and if they are the same we know the speed is same in both directions, right ??
Thanks you’ve distracted me from my engineering finals by making me question a convention of physics.
And this is why spooky action at a distance shouldn't be so surprising
Perfect Idea for Christopher Nolan for his next movie.
Boy that guy make any scientific concepts into blockbusters,
yessirrrr
@Meggion Well, yes... Thorne was credited as the scientific consultant for the movie. Of course Nolan didn't invent the scientific concepts for Interstellar. What's the point of your comment?
Yes!!
This video contains errors, I think Nolan has good physics advisors.
"This is breaking my brain." Exactly how I felt.
@Tyler B #2 bait lmfao
@@ameliamelton6566 Ha ha! Exactly!!!!
This guy, tony stark lookin, type, Bruce banner
How about using quantum computer entanglement to sync the two clocks and measure the light in a single direction?
Indeed
"Or have they?"
Hey VSauce! Michael Here
Tohba tohba tohba mood kharab kar diya
Abbe saale
🤣🤣🤣
That would be such a collab!
Derek already did one with Michael but not with Destin in one video.
@@NimbleBard48 We all want that to happen💥💥💥
Use camera A for a live video call from camera 2 to view clock 2. Record the moment light leaves at point A from camera 2’s clock and when it reaches clock 2 in the live video feed from camera 2. If you are only observing clock 2 from a live video feed and recording the time when the light reaches it, you would be eliminating the need for precise clock synchronization between clock 1 and clock 2.
“Why has no one measured the speed of light yet?”
the thumbnail: *”it’s impossible”*
welp my time here is done
Fr
Welp carry on
like whats even the point of watching
@@av8077 To understand why ig
I mean, if I as panicking on a way to save my loved one and the doctors outright told me it's impossible, that would not bring me any closure or explanation to the reason. So in the same way we ask why and we get the answer being impossibility, we aren't brought closure and explanation on a major physics study.
Now wooosh me :)
@@Ins1gn1f1c4nt not r/Woooosh
17:01
"And we'll wonder, why we didn't c it before?"
Amazing!
g, I'm not sure...
This tickled my brain in all the right ways.
Tickle tickle.
In all the light ways
That’s what she said
-micheal Scott
Everything travels at the speed of light through spacetime so there is always that discrepancy, but it can NEVER change the result of an experiment. It also might not even make sense to ask the question in other words it may be a "confused question". I for one believe that it is a "confused question", but that still may be "just a convention".