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.
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 :)
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.
@@DownToTheWire0you use one clock. Just two mirrors. But that assumes the universe doesn’t average different speeds at different directions to keep the OBSERVER synchronized
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
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.
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.
Also, what about balck holes ? From the BH perspective, if there is a prefered direction with an instentaneous speed, this means we would be able to see the singularity, therefore breaking physic ? Right ?
Take a uniform solid of appropriate length. Attach light timers at either end such that the timers calibrate when disturbed to a particular amplitude. Propagate a wave of appropriate amplitude starting at the center of the uniform mass. Now your timers should be calibrated. Shoot your light both ways and find C. Repeat until N is meaningful.
well, not exactly no, we cant see the singularity, as in a black hole space is infinite but time is finite, which means therefor a singularity is not right infront of us, it is in our futures, so if we can see them physics is broken. but no we cannot see the singularity. or we shouldn't be able to.
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.
@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
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
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
Why not have two light sources in middle both aimed at opposite directions at their respective clocks. We fire both lights up at the same time and see if there’s a difference in time on both clocks. Would that work?
@@michalw6965doesn't instant travel violate conservation of energy? Light just somehow got enough energy to instantly travel back to its exact spot where that star or thing might not even be meaning it would need to remember the x,y, and z coordinates
Absolutely LOVE Ur Channel !! Especially episodes like this 1, when U bend my brain into complex knots ! Thanx for being so Amazing, and showing Us all the inner workings of this reality we live in.
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 :)
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)....
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.
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.
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🧠
🎯 Key points for quick navigation: 00:00:31 *📏 The speed of light (299,792,458 meters per second) defines the length of a meter but hasn't been measured in the same way as other speeds.* 00:02:07 *⏱️ Measuring the one-way speed of light requires synchronized clocks, which is complicated by relativity since moving clocks experience time dilation.* 00:03:34 *🔄 The speed of light has only been measured for round trips, like in Fizeau's 1849 experiment, not for one-way journeys.* 00:04:34 *🤔 It's theoretically possible that the speed of light varies by direction, affecting communication without being detected.* 00:06:37 *⚖️ Einstein's synchronization convention, assuming light speed is the same in both directions, is a matter of definition, not experimental proof.* 00:10:35 *⚡ Even systems like GPS assume equal speed of light in all directions; alternative speeds would disrupt clock synchronization but are undetectable.* 00:12:38 *🕒 Synchronization methods break down if light speed is unequal, causing discrepancies in perceived simultaneity across distances.* 00:14:08 *🌌 The concept that events happen "now" across vast distances is ambiguous without a constant one-way light speed.* 00:16:06 *🧠 One-way light speed's empirical indefiniteness poses intriguing questions about time, space, and future physics paradigms.* 17:13 *🎁 KiwiCo sponsors the video, offering educational project kits that foster learning and creativity, with a discount for viewers.* Made with HARPA AI
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
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.
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
How about firing the stopwatch on two ends twice? Like first one starts by sending light, then sends second light at exactly 10 seconds. The second one starts when catching light, and then we subtract 10 seconds from the final result when second beam of light is received?
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
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?
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.
@@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 😅).
@@giacomogroppi5768 No, the shadow is not instantaneous. The light that passed the object before the rest is blocked will still be visible until the last unblocked light reaches the surface of the observation.
You suggest measuring the two-way speed of light using a mirror. My question is - a mirror is a physical object, reflecting back the light is some physical process or reaction, doesn't it take some time too? Maybe the total time we then measure is T1 a to b + T2 mirror reaction time + T3 b to a.
Since light, in a vacuum, always travels at c, there’s no turnaround time. The photon travels at c towards the mirror, then either it’s direction is reversed and the velocity of c is going the other way or the photon penetrates the mirror and goes through to the other side or the photon is absorbed by the mirror
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?
9:05 assumes that all directions lights travels in is calculated in the study. When considering how fast it takes for light to travel to the camera, it is not 2 way. The camera is just recording an event. The distance between Point A and point B have nothing to do with the perpendicular distance between the photons of “a laser” being recorded to calculate the speed of light using a camera.
If C varied directionally, wouldn't the galaxies in one direction look older than the ones in the opposite direction? Would the effect be large enough to measure? If C traveled half the speed when moving toward Earth from a certain direction, then the galaxies in that direction would appear half as old as the ones in the other direction, right?
@@everything1023 your assuming with using redshift the most extreme example of instantaneous time travel but the galaxy problem could be explained by different expansion rates of the universe or smth else
@@wolf-xf6hf but why would redshift not work? I mean in the end we can fire a laser into a photodetector and see exactly when it hit. Atomic clocks can be extremely accurate. If the barrel is long enough, we would most definitely be able to read the speed. The only real problem would be for the hit to stop a timer instantaneously, but that can be averted.
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
@@kevoramma great point! Thank you for using UA-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 👍🏻
Can there not be a detector on the other side that once it receives light sends another beam back so there are two beams of light and therefore you can deduce the speed of light total time vs the time that the secondary detector takes to hit the original side. Interested to see why this is almost certainly wrong.
"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
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.
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.
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?
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.
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.
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.
@@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.
An idea for measuring the one-way speed of light using a black hole: Create a device which will emit a pulse of light and start a timer at the same time, with a sensor on the back that stops the timer when it detects the light emitted. Find a suitable black hole and calculate at what distance from it the light would have a stable enough orbit to hit the back of the device. Send the device in, and measure. We almost definitely wouldn't be able to retrieve the data, but the one-way speed of light would be measured nonetheless. (I may be missing a fundamental problem with this solution, other than the fact that it is probably impossible to test even if the idea is theoretically sound, but it just popped into my head and I haven't had time to properly look into it yet)
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?
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.
i think a valid question here is: "does it matter?" not because pure abstract physics/math doesn't, but because once we find an application where the models may lead to different results, at the same time we find a hint to find which model is truthful. if a scenario where the models lead to different results turns out to not exist, could it be seen as "fake" artificially introduced variable? like the y in 2x + 0y = 1, i might add as many "y" variables as i want. So would that make the "different" models to be the same? i'm not sure about those last parts.
@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
I'm having trouble agreeing on 13:18 diagrams in the video. if earth sent a message containing a time stamp of 1200hrs and mark on mars receives it at 1220hrs and then immediately replies the message with a time stamp of 1220hrs and sends it, but this round with the concept that the reply is instantaneous, wouldn't earth notice the radio waves' behaviour since they themselves would compare the time stamp on the mars message with their local time as being the same that is 1220hrs? Hence they would have an accurate system to measure these waves which is " (distance/time) + infinity " example using a simple dialogue plus the math ; EARTH: [Message sent at 1200hrs] Hi Mark. MARK (From Mars): [Message received at 1220hrs] (immediately opens received message and reads, " [Message sent at 1200hrs] Hi Mark.") MARK (From Mars): [Message sent at 1220hrs] Hi Earth. EARTH: [Message received at 1220hrs] (immediately opens received message and reads, " [Message sent at 1220hrs] Hi Earth.") shortest distance from earth to mars = 54500000000meters time taken for mark to receive message = (20 * 60) seconds time taken for earth to receive reply = infinity (f) hence speed of radio wave messages to and back = (distance/time) + infinity that is; (54500000000/1200) + f therefore = (45,416,666.66666667 + f) meters per second Note: time and distance are close estimates) So unless I'm wrong, one way speed of light can be estimated or measured given that radio wave speed is equal to speed of light. I'm done. My brain hurts!
Clearly I'm missing something here! How about two identical toothed wheels at either end of a spinning shaft? Shine light through the one wheel and speed up the spin of the shaft till the light doesn't get through the second wheel. Then turn the shaft in any direction you want, and repeat the measurement.
2:54 The best thing to do is to use a refractor and you only need one clock to start and stop no interruptions. Then I probably wouldn't use a mirror I would do something more like fiber optic so when you bend the light you don't inhibit its speed
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.
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.
Laws of this universe; -- Perfection, is Imperfection ! -- Never use the word "never" ! ************ -- Time-frames of 1*ly to 1/ly (by mathematics) -- Universe has Non-uniform properties -- Universe demonstrates effects of outside forces >>> "Perfection"
At 14:08 he says "Any other convention is hust as valid, upto and including one where the speed of light is C/2 one way and instantaneous the other way.". Is there anything stopping you from going further? Like a 20 minute round trip taking 30 minutes one way and going back in time 10 minutes the other way. Does anything break or does it cancel out the differences and still just work?
You could know how much the clocks are off from eachother before you shoot the beam you are assuming 1 real observer observing two objects. Just take off the difference between the clocks... which was taken prior to the test where there is more than one controller.... There is much better tech now to test this, I could set this up with a couple of arduinos rofl. Likely the ray out has more momentum then the ray back....
@64PINK256 @Sciece Revolution. This is kinda a pun related thread. You're certainly welcome to comment here but you'll likely get more visibility at the top level, because, as we all know, everything depends on your flame of reference.
@@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 :)
Do we agree sound waves propagate at the same speed in all directions? What’s stopping a central point from emitting a sound and light at the same time, then measuring the delay between the two from observation points in all directions? If the speed of light is different in some directions then some observation points would measure a different delay, right?
In the late 1870's two scientist Michelson and Moreley spent a year measuring the speed of light. They measured the speed of light in the direction of the Earth's motion around the sun and in the opposite direction. They measure the speed of light as a light source coming at them and a light source moving away from them. In all situations the speed of light remained the same. As a result of this experiment Einstein developed the theory of Relativity. To explain the Michelson-Moreley experiment of speed of light remaining constant Einstein showed that time was not constant and varied to each observer.
Einstein claims to have come to the conclusion of special relativity without knowledge of the result of the Michelson-Morley experiment, also they performed it year round, to attempt to measure the 'ether' drag. Ideally this would be greatest in opposite directions, but without knowing which way it flows they wouldn't know which times of year they would be moving directly in the direction of the ether current or directly against it. If you ever want a really good summary of many of these experiments, AP French's special relativity book which is still an MIT special relativity staple has a great chapter on the subject matter :)
@Shina Well as a physicist I'd love for you to enlighten me. Do explain! Additionally, could you explain why the movement of the galaxy rules out Earth's movement around the sun? Is your claim that the galaxy moves anti-symmetrically with the Earth to eliminate drag in any direction?
@Shina What you wrote is not the definition of "calibration", and that you did not realize that may be why @Karkess asked you the other question, to discuss how you know the earth movement is moot because no one knows how fast or in what way the galaxy is moving. (Hint: yes, "people" do know, and so can you if you knew how to do it)
@Shina I am out of my depth? Well that's a nice way to have a dialog. Your attempted insult is not very nice and indicates maybe you just want to put others down to build yourself up. Not a way to actually engage in a healthy discussion. Nevertheless, what you describe "lining up mirrors till a result is observed" is not calibration, it is the experiment itself. Calibration is assuring all the equipment used is working to specification, within the range of accuracy and uncertainty. Once this is all calibrated, specifically here the time and distance and other physical attributes, the experiment begins and the result found, within the accuracy of the equipment. Is this not how you have performed experiments? Or did your university state when you observe a result it is "calibrated"? (which is not true; one can get a result without the equipment being calibrated). As for reference point for the universe, well that's what's cool about science; sometimes you get to define your reference point and say things like "the velocity relative to the location XYZ" which is what we do, because the universe has no center. So we define some location and relate velocity to that, and all is well. That's how most people do it, how do you do it?
17:51 - why not put a single clock in the center and fire two lasers at the clock with the beams traveling 180 degrees opposite of each other (both toward the center clock).
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
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
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 :)
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.
@@DownToTheWire0you use one clock. Just two mirrors. But that assumes the universe doesn’t average different speeds at different directions to keep the OBSERVER synchronized
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
This is amazing, I already knew this problem, but no one has ever been able to explain it so well. Congratulations to the channel.😊
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 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 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.
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.
Also, what about balck holes ? From the BH perspective, if there is a prefered direction with an instentaneous speed, this means we would be able to see the singularity, therefore breaking physic ? Right ?
Also light is bent by gravity from Galaxies so it goes Further than it would in a straight line.
The expansion of the universe causes redshift (it's related to distance the light travelled, not the time which is hypothetically variable)
Take a uniform solid of appropriate length. Attach light timers at either end such that the timers calibrate when disturbed to a particular amplitude. Propagate a wave of appropriate amplitude starting at the center of the uniform mass. Now your timers should be calibrated. Shoot your light both ways and find C. Repeat until N is meaningful.
well, not exactly no, we cant see the singularity, as in a black hole space is infinite but time is finite, which means therefor a singularity is not right infront of us, it is in our futures, so if we can see them physics is broken. but no we cannot see the singularity. or we shouldn't be able to.
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
4:06 - "Or have they?"
I feel like this was a missed chance to put the vsauce theme on
Also noticed VSause referenceh
Here
ua-cam.com/video/dQw4w9WgXcQ/v-deo.html
this is depressing here the right url ua-cam.com/video/xuCO7-DLCaA/v-deo.html
Moon Men by Jake Chudnow
(Vsauce theme) - ua-cam.com/video/TN25ghkfgQA/v-deo.html
ua-cam.com/video/YgiyWGyJcIc/v-deo.html
"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
As usual, a brilliant, thought provoking video. Thanks and I look forward to more.
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
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
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
Why not have two light sources in middle both aimed at opposite directions at their respective clocks. We fire both lights up at the same time and see if there’s a difference in time on both clocks. Would that work?
But you would need to synchornise both clocks and it is imoossibke with diferent speeds of light
@@michalw6965doesn't instant travel violate conservation of energy? Light just somehow got enough energy to instantly travel back to its exact spot where that star or thing might not even be meaning it would need to remember the x,y, and z coordinates
@ I didn’t say it has to be instant travel, it can be just a little bit faster one way than the other
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
"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
"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...
Absolutely LOVE Ur Channel !!
Especially episodes like this 1, when U bend my brain into complex knots !
Thanx for being so Amazing, and showing Us all the inner workings of this reality we live in.
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 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 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.
Happy Birthday, Derek! You are a beacon of light in this dark, dark world.
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.
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.
"Stars look exactly as they are right this instant." Gave goosebumps.
ua-cam.com/video/nRGCZh5A8T4/v-deo.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🧠
🎯 Key points for quick navigation:
00:00:31 *📏 The speed of light (299,792,458 meters per second) defines the length of a meter but hasn't been measured in the same way as other speeds.*
00:02:07 *⏱️ Measuring the one-way speed of light requires synchronized clocks, which is complicated by relativity since moving clocks experience time dilation.*
00:03:34 *🔄 The speed of light has only been measured for round trips, like in Fizeau's 1849 experiment, not for one-way journeys.*
00:04:34 *🤔 It's theoretically possible that the speed of light varies by direction, affecting communication without being detected.*
00:06:37 *⚖️ Einstein's synchronization convention, assuming light speed is the same in both directions, is a matter of definition, not experimental proof.*
00:10:35 *⚡ Even systems like GPS assume equal speed of light in all directions; alternative speeds would disrupt clock synchronization but are undetectable.*
00:12:38 *🕒 Synchronization methods break down if light speed is unequal, causing discrepancies in perceived simultaneity across distances.*
00:14:08 *🌌 The concept that events happen "now" across vast distances is ambiguous without a constant one-way light speed.*
00:16:06 *🧠 One-way light speed's empirical indefiniteness poses intriguing questions about time, space, and future physics paradigms.*
17:13 *🎁 KiwiCo sponsors the video, offering educational project kits that foster learning and creativity, with a discount for viewers.*
Made with HARPA AI
Great, ai garbage in the comments
"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!
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
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
How about firing the stopwatch on two ends twice?
Like first one starts by sending light, then sends second light at exactly 10 seconds.
The second one starts when catching light, and then we subtract 10 seconds from the final result when second beam of light is received?
“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
“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.
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?
What about Maxwell's equations? Don't they contain the speed of light within themselves? Aren't they valid for each system in each orientation?
"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....
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
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
I always love these types of videos, they always show just how little we actually know about the universe we all live in!
"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?😢
“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 😅).
Everyone gangsta until someone calculated the speed of shadow
Heyyyy vSauce, Michael here
Its istantaneous because it doesnt carry information (so it could go above c)
Hey Michael, vsauce here
@@giacomogroppi5768 No, the shadow is not instantaneous. The light that passed the object before the rest is blocked will still be visible until the last unblocked light reaches the surface of the observation.
@@ozciva but it’s still the same thing... how do you measure the speed of the shadow accurately?
The fact that the video lasts exactly 19:05, the year Einstein wrote his article.
"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
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?"
Lol
But the aliens can't know what a monkey is and they probably won't be able to speak English (I know it is just a joke)
@@shivannapv4262 nasa would like to hire you
@@omniyambot9876 why (I still know its a joke)
@@shivannapv4262 because biden is gonna be the new president😄😄😄😄
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
You suggest measuring the two-way speed of light using a mirror. My question is - a mirror is a physical object, reflecting back the light is some physical process or reaction, doesn't it take some time too? Maybe the total time we then measure is T1 a to b + T2 mirror reaction time + T3 b to a.
And of course, thank you for creating this wonderful and interesting video.
Since light, in a vacuum, always travels at c, there’s no turnaround time. The photon travels at c towards the mirror, then either it’s direction is reversed and the velocity of c is going the other way or the photon penetrates the mirror and goes through to the other side or the photon is absorbed by the mirror
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?
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
"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????
9:05 assumes that all directions lights travels in is calculated in the study. When considering how fast it takes for light to travel to the camera, it is not 2 way. The camera is just recording an event. The distance between Point A and point B have nothing to do with the perpendicular distance between the photons of “a laser” being recorded to calculate the speed of light using a camera.
The moment when Destin realized "Oh snap, Derek is going relativity• is Golden!
Where does the quotation end?
17:01
"And we'll wonder, why we didn't c it before?"
Amazing!
g, I'm not sure...
If C varied directionally, wouldn't the galaxies in one direction look older than the ones in the opposite direction? Would the effect be large enough to measure? If C traveled half the speed when moving toward Earth from a certain direction, then the galaxies in that direction would appear half as old as the ones in the other direction, right?
Yes. This is what I was thinking.
Yeah I feel like there are a lot of problems with what this guys says.
Wouldn’t this also mean redshift shouldn’t exist?
@@everything1023 your assuming with using redshift the most extreme example of instantaneous time travel but the galaxy problem could be explained by different expansion rates of the universe or smth else
@@wolf-xf6hf but why would redshift not work? I mean in the end we can fire a laser into a photodetector and see exactly when it hit. Atomic clocks can be extremely accurate. If the barrel is long enough, we would most definitely be able to read the speed. The only real problem would be for the hit to stop a timer instantaneously, but that can be averted.
Someone said , "There is no time, only clocks and none of them agree". Thanks, I always enjoy this channel!
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
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)))
That was actually one of the best things I’ve ever seen on UA-cam. Excellent work!
I see no reason to use the word “actually” here.
@@kevoramma great point! Thank you for using UA-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?? 😂😂😂
Can there not be a detector on the other side that once it receives light sends another beam back so there are two beams of light and therefore you can deduce the speed of light total time vs the time that the secondary detector takes to hit the original side. Interested to see why this is almost certainly wrong.
The problem is how would you sync the clocks.
"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
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?
A micro millisecond: The time between when you shut, and lock your car door, and realize you left your keys inside.
What if the realization happens before the door shuts, but too late to stop it?
@@davidpowers746 We are talking reverse space time continuum. Way past my realm of comprehension.
@@treeguyable The physics isn't ripe yet.
The onosecond
@@WilliamSmithIV oh, … OH, NOoo! Seconds, …
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.
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.
"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
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?
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.
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.
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 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.
An idea for measuring the one-way speed of light using a black hole:
Create a device which will emit a pulse of light and start a timer at the same time, with a sensor on the back that stops the timer when it detects the light emitted. Find a suitable black hole and calculate at what distance from it the light would have a stable enough orbit to hit the back of the device. Send the device in, and measure. We almost definitely wouldn't be able to retrieve the data, but the one-way speed of light would be measured nonetheless.
(I may be missing a fundamental problem with this solution, other than the fact that it is probably impossible to test even if the idea is theoretically sound, but it just popped into my head and I haven't had time to properly look into it yet)
where can I buy a black hole to test this theory with a lamp?
@@sal_playz6029 I think they might have some left on the intergalactic black market...
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?
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*
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
i think a valid question here is: "does it matter?"
not because pure abstract physics/math doesn't, but because once we find an application where the models may lead to different results, at the same time we find a hint to find which model is truthful.
if a scenario where the models lead to different results turns out to not exist, could it be seen as "fake" artificially introduced variable?
like the y in 2x + 0y = 1, i might add as many "y" variables as i want.
So would that make the "different" models to be the same? i'm not sure about those last parts.
"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
@@فكرة.في.دقيقة Stop spamming this.
Veritasium basically is VSauce nowadays
This was the most elaborate, philosophical, mind-boggling, brain bending, insightful, confusing way of saying: We Can’t.
"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*
I'm having trouble agreeing on 13:18 diagrams in the video. if earth sent a message containing a time stamp of 1200hrs and mark on mars receives it at 1220hrs and then immediately replies the message with a time stamp of 1220hrs and sends it, but this round with the concept that the reply is instantaneous, wouldn't earth notice the radio waves' behaviour since they themselves would compare the time stamp on the mars message with their local time as being the same that is 1220hrs? Hence they would have an accurate system to measure these waves which is " (distance/time) + infinity "
example using a simple dialogue plus the math ;
EARTH: [Message sent at 1200hrs] Hi Mark.
MARK (From Mars): [Message received at 1220hrs]
(immediately opens received message and reads, " [Message sent at 1200hrs] Hi Mark.")
MARK (From Mars): [Message sent at 1220hrs] Hi Earth.
EARTH: [Message received at 1220hrs]
(immediately opens received message and reads, " [Message sent at 1220hrs] Hi Earth.")
shortest distance from earth to mars = 54500000000meters
time taken for mark to receive message = (20 * 60) seconds
time taken for earth to receive reply = infinity (f)
hence speed of radio wave messages to and back = (distance/time) + infinity
that is;
(54500000000/1200) + f
therefore = (45,416,666.66666667 + f) meters per second
Note: time and distance are close estimates)
So unless I'm wrong, one way speed of light can be estimated or measured given that radio wave speed is equal to speed of light.
I'm done. My brain hurts!
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.
Cop: Do you know how fast you were going?
Werner Heisenberg: No, but I know where I am.
Cop: You were going 80 in a 60.
Heisenberg: Oh great! Now I'm lost!
Phoetonic pike pressure at destination
Einstein solved the uncertainty principle right?
@@sangeethasivan3025 I don't think there is a solution to the uncertainty principle? It's, as far as we know, a fundamental facet of quantum physics.
Clearly I'm missing something here! How about two identical toothed wheels at either end of a spinning shaft? Shine light through the one wheel and speed up the spin of the shaft till the light doesn't get through the second wheel. Then turn the shaft in any direction you want, and repeat the measurement.
"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💥💥💥
2:54 The best thing to do is to use a refractor and you only need one clock to start and stop no interruptions. Then I probably wouldn't use a mirror I would do something more like fiber optic so when you bend the light you don't inhibit its speed
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.
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.
Law zero of physics: Einstein always has the last laugh.
Until Veritasium was born.
Very unscientific
@@ebrelus7687 How is it unscientific if it's based on all evidence so far and is testable?
As a general theorie of relativity nerd i agree
Laws of this universe;
-- Perfection, is Imperfection !
-- Never use the word "never" !
************
-- Time-frames of 1*ly to 1/ly
(by mathematics)
-- Universe has Non-uniform properties
-- Universe demonstrates effects of outside forces
>>> "Perfection"
At 14:08 he says "Any other convention is hust as valid, upto and including one where the speed of light is C/2 one way and instantaneous the other way.".
Is there anything stopping you from going further? Like a 20 minute round trip taking 30 minutes one way and going back in time 10 minutes the other way. Does anything break or does it cancel out the differences and still just work?
My physics teacher: You got an F because you wrote down the speed of light wrong.
Me:
🤣
Imagine you, saying that to your teacher, with that one punch man face
🤣👌
“and we’ll wonder why we didn’t C it before”. Perfect pun!!
Haha nice one.
I don't have time for this.
You could know how much the clocks are off from eachother before you shoot the beam you are assuming 1 real observer observing two objects. Just take off the difference between the clocks... which was taken prior to the test where there is more than one controller.... There is much better tech now to test this, I could set this up with a couple of arduinos rofl. Likely the ray out has more momentum then the ray back....
YO THERES A REAL BATTLE HERE
@64PINK256 @Sciece Revolution. This is kinda a pun related thread. You're certainly welcome to comment here but you'll likely get more visibility at the top level, because, as we all know, everything depends on your flame of reference.
“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
Do we agree sound waves propagate at the same speed in all directions? What’s stopping a central point from emitting a sound and light at the same time, then measuring the delay between the two from observation points in all directions? If the speed of light is different in some directions then some observation points would measure a different delay, right?
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...
In the late 1870's two scientist Michelson and Moreley spent a year measuring the speed of light. They measured the speed of light in the direction of the Earth's motion around the sun and in the opposite direction. They measure the speed of light as a light source coming at them and a light source moving away from them. In all situations the speed of light remained the same. As a result of this experiment Einstein developed the theory of Relativity. To explain the Michelson-Moreley experiment of speed of light remaining constant Einstein showed that time was not constant and varied to each observer.
I believe they measured the two way speed in perpendicular directions.
Einstein claims to have come to the conclusion of special relativity without knowledge of the result of the Michelson-Morley experiment, also they performed it year round, to attempt to measure the 'ether' drag. Ideally this would be greatest in opposite directions, but without knowing which way it flows they wouldn't know which times of year they would be moving directly in the direction of the ether current or directly against it.
If you ever want a really good summary of many of these experiments, AP French's special relativity book which is still an MIT special relativity staple has a great chapter on the subject matter :)
@Shina Well as a physicist I'd love for you to enlighten me. Do explain!
Additionally, could you explain why the movement of the galaxy rules out Earth's movement around the sun? Is your claim that the galaxy moves anti-symmetrically with the Earth to eliminate drag in any direction?
@Shina What you wrote is not the definition of "calibration", and that you did not realize that may be why @Karkess asked you the other question, to discuss how you know the earth movement is moot because no one knows how fast or in what way the galaxy is moving. (Hint: yes, "people" do know, and so can you if you knew how to do it)
@Shina I am out of my depth? Well that's a nice way to have a dialog. Your attempted insult is not very nice and indicates maybe you just want to put others down to build yourself up. Not a way to actually engage in a healthy discussion. Nevertheless, what you describe "lining up mirrors till a result is observed" is not calibration, it is the experiment itself. Calibration is assuring all the equipment used is working to specification, within the range of accuracy and uncertainty. Once this is all calibrated, specifically here the time and distance and other physical attributes, the experiment begins and the result found, within the accuracy of the equipment. Is this not how you have performed experiments? Or did your university state when you observe a result it is "calibrated"? (which is not true; one can get a result without the equipment being calibrated). As for reference point for the universe, well that's what's cool about science; sometimes you get to define your reference point and say things like "the velocity relative to the location XYZ" which is what we do, because the universe has no center. So we define some location and relate velocity to that, and all is well. That's how most people do it, how do you do it?
It turns out the speed of light is C/3 and the return trip goes back in time.
correct until proven wrong :D
Or irrelevant until proven right. So prove it!
@@lexxfirecore123 Nope, not how physics works. Not how *any* of this works.
Photos dont experience time.
@@rebelquadronfpv1065 it was a joke
17:51 - why not put a single clock in the center and fire two lasers at the clock with the beams traveling 180 degrees opposite of each other (both toward the center clock).
How do you know when to shoot the lasers?