I swear this channel is a gold mine for educational and entertaining content

If the light waves from the sun were 8 minutes and 20 seconds in a past dimension of Einstein's space-time then people on Earth are just imagining the infrared warmth of the sun coming up on the horizon. The communications delay between Earth and Mars is approximately 20 minutes. We're either viewing the light from Mars in the future, Einstein's past dimensions of space-time or in real time, which do you think is more logical? Einstein's relativity is wrong light has no limitation of speed; it cannot be slowed down because it isn't moving. From every vantage point in the universe light is omnidirectional-instantaneously traveling in both directions. Light and electromagnetic waves are independent of each other. According to Einstein's relativity-time dilation's, photos taken of the Earth from the Discovery Space station traveled from the past to the future violating the laws of physics, conservation of energy and common sense. According to Einstein's projectile light particle proton light has a (constant speed) of 186,000 miles per second moving through spacetime, but if light has a (constant speed) then moving clocks cannot run slow through spacetime! :-) If a Big Bang alien astronomer just discovered our Milky Way galaxy and claimed it was 13.8 billion years in a past dimension of Einstein space-time then people on earth won't exist for another 13.8 billion years. The speed of light according to Einstein's relativity is 186,000 miles per second, but according to physics if two mechanical watches were synchronized on earth and one traveled across the universe and back, there would be no difference in time between the mechanical watches proving the speed of light is instantaneous as the only way a mechanical watch will run slow is if you tighten the main spring. Big Bang, Einstein's relativity-time dilation and nearly all of science debunked. Using optical clocks, lasers and GPS to prove Einstein's time dilation-space-time curvature is like using a metal detector to find gold at Fort Knox. The closer you are to the electromagnetic fields, mass and gravity of the earth the more light bends aka gravitational lensing. If the speed of light is constant then past and future dimensions of spacetime and an expanding universe would not be possible, obviously destroying the twins paradox as each twin cannot move faster or slower than the other. A mirror is a wave reflector that flips images from left to right, but according to Einstein the images you see are the result of projectile light particle photons being transported into past and future dimensions of space-time. Explain how particle light photons can re-converge their molecular structures in mirrors and how this is done without violating the law of conservation of energy. From every vantage point in the universe light is omnidirectional-instantaneously traveling in all directions (forwards and backwards through Einstein's space-time) while violating the law of conservation of energy. Explain how Einstein's projectile light particle proton can travel all directions having a (constant speed) of 186,000 miles per second. Einstein would have made a great used car salesman :-). Light waves can stretch, bend-curve and occupy a state of superposition, whereas the hypothetical Einstein projectile light particle (photon), a particle that has never been observed cannot. Unlike a TV or computer monitor the images we are viewing in the universe are in real time, not a series of frames that create the appearance of a moving image. There are no DCU digital convergence circuits in space yet Einstein's disciples believe the light and moving images they see in the universe aren't really there, they're just video recorded images of the past 13.8 billion years. You could lead a cult to water, but you can't make them think. Neither time, energy nor mass can create itself into nothing, reside in nothing or expand into nothing simply because nothing has no properties. Time and space are independent of each other, not material bodies or fantasy unions that magically stretch Time, energy, and matter like a rubber band into space-time dimensions. Einstein's projectile light particle proton has a (constant speed) of 186,000 miles per second moving through spacetime and because so wavelengths of light cannot stretch through spacetime! Red-shifts are simply the result of decelerating electrons, as moving electrons of charged electromagnetic waves-light travel through the plasma of the universe each lump (or "quanta") of energy in the electromagnetic waves are charged then discharged to the next lump, eventually the energy dissipates causing the delay in radio communications giving the appearance of time dilation - longer wavelengths in red shift. Will the James Webb Telescope view the birth of the first galaxies? Nope, the universe goes on to infinity. Neither time, the atom, energy nor mass can create itself into nothing, reside in nothing or expand into nothing simply because nothing has no properties. The James Webb Space Telescope is not a time machine, you can’t travel back in time to view the beginning of the universe with telescopes that were made in the future :-). Light and electromagnetic waves are independent of each other. If science uses Einstein's wrongly theorized speed of light like an odometer to calculate past dimensions of distance and time, then using that same method to calculate forward dimensions of distance and time would mean the Big Bang was created and expanded in the future before time existed. Unlike a television or computer monitor the images we are viewing in the universe are in real time, not a series of still image frames that hypothetical Einstein projectile light particles photons create to give us the appearance of a moving image :-). The speed of electromagnetic wave is 186,282 miles per second vs Einstein's projectile light particle proton at 186,000 miles per second. Is this a coincidence or did Einstein plagiarize yet another phenomenon to fit the math of relativity? Electromagnetic waves in space can neither slow down or speed up, this is consistent with the law of conservation of energy. If light slowed down, its energy would decrease, thereby violating the law of conservation of energy so the speed of light is instantaneous and cannot travel slower than it does. If Einstein's projectile light (particle photon) had mass it's light could not travel across the universe, high speed particles traveling at 186,000 miles per second would break the Hubble and James Webb telescope mirrors, debunking the speed of light, Big Bang, Einstein's relativity and any science that uses relativity in their theories. Everyone knows cell phone electromagnetic radio waves travel both ways, yet Einstein's disciples believe time energy, mass and light can only travel one way back in time. If you simply run the Big Bang theory in reverse you reveal the insanity of Einstein's relativity and Big Bang theory. If the expansion of the Big Bang were true, time, energy, mass and light would be in the future from the vantage point of an expanding singularity-Big Bang and planet Earth would now reside in a past dimension of Einstein's time dilation (moving clocks run slow) space-time 13.8 billion years ago :-). From every vantage point in the universe light is omnidirectional-instantaneously traveling in both directions (forwards and backwards through Einstein's space-time) while violating the law of conservation of energy. Explain how Einstein's projectile light particle proton can travel in both directions having a (constant speed) of 186,000 miles per second :-) It's truly amazing how the science and politics of the left are able to keep people denying reality, there are no DCU digital convergence circuits in space, yet Einstein's disciples believe the light and moving images they see in the universe aren't really there, they're just recorded images of the past 13.8 billion years. Pretending not to notice the gross contradictions-pseudoscience in Relativity is typical of Einstein's disciples, devaluing the source of any information that's in contradiction with their beliefs-theories. You could lead a cult to water, but you can't make them think. If the light from the universe travels to past dimensions of time then it's light is also traveling into future dimensions of time (instantaneously). “And God said, Let there be light: and there was light.” a state of superposition where time and gravity run inwardly, outwardly, in all directions in the same time frame, similar to the electromagnetic field having no beginning and no end. "I am the Alpha and the Omega, the First and the Last, the Beginning and the End" Revelation 22:13. Disciples, remember thy 1st commandment, thou shalt not question thy lawgiver of relativity for blasphemers are the devil's pawn. Let thee not dwell in dissension of our Lord Albert, shun them, drive them back to their jungle lair amen. Albert Einstein, an autistic violinist patent clerk that had access to more papers than Suzanne Somers litter box yet creates theories with more bugs than Terminix- Magnetron

@Automatiic I just got your message at the same time! Wait can we measure this?

Educational?? You’ve got to be kidding..

love your name xD

Beware! an element of truth and it can be interpreted

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.

@Hugh Perkins originally, yes, you are correct. Since the original experiment, many different configurations, geometries, and gases have been tried

Well, you forget the Lorenz contraction. If, in the slow direction the measuring device contracted (due to some physical force from the rather) the results would be the same. However, combine MM measurements with the double-slit, nuclear, cyclotron, and photovoltaic experiments and it’s very difficult to posit anything other than constant C.

@sam The problems seems to be related to the direction the light travel. In the case of the 2 robots, the signal from the switch will travel to each robot in a different direction and we are back to the problem of "maybe the direction affect the speed". But if you repeat the experiment with the 2 robots with different orientations; like pointing north-south then east-west, etc, I would guess that if the measurement is always the same, then direction is not a factor.

@sam Definitely different things! Go check out the Michelson and Morley experiment on the wikipedia and you can get the gist from a quick read.

@Karkess I thought it was called dark matter, or are we talking about different things?

This reminds me of my aviation days when I would work roundtrips between Toronto and Vancouver. It would always even out to a solid 10-hour day, but the trip was always way faster in one direction and way longer coming back (which varied daily). You would never know it if you were only consistently measuring the roundtrip. The sum of both flight-times was always the same.

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I have watched this video several times within the past 2 years and it has never failed to make me wonder. There is obviously a way that the universe communicates to itself. A way in which it handshakes with itself to keep the laws and the rules of its existence intact. Could it be that there is an instantaneous corridor of communication that light utilizes to convey the rules of existence throughout the universe. To keep everything playing by the same rules. Great video keep it coming and keep twisting Justin's brain. 😂😂😂😂

Mee too !!!

Hey Derek, Particle Physics student here, I never thought about this. Wouldn’t the CMBR have a directional bias if the speed wasn’t the same in all directions? We might also be able to observe some periodicity in the sun and it’s processes as we moved around in our orbit?

Hello anonymous person. I agree with you! If we get our exact position on space, it would be possible to notice the speed of light by finding the exact position of the sun right now and then within 6 exactly months, allowing us to figure out whether the speed of light is or isn't the same in both directions And we could call it the late sun hypothesis, given the sun would shine 16 minutes late and then immediately half a year ago hehehehaha

@Pierre Dunn The video poses an interesting problem, but it’s conclusion is a little overstated. It is not possible to know the one-way speed perfectly. However, it is possible to know the one-way speed to 0.00001% or so. Interestingly enough, we can know the average 2-way speed (round-trip time) to only a little bit more accurately. It is true that the speed could fluctuate wildly during its trip and we would not know it. So far, no experiment performed shows any hint of this extreme fluctuation. If C was not constant then 300 years of physics would need redoing. While I hate Occam’s razor for its constant misuse, this is a case where it applies - all else being equal, the simpler theory is usually the correct one. A constant C is the simpler theory. As for time-traveling photons-as far as photons are concerned, there is no time. However, we are not photons, so time applies to us, and time only flows in one direction.

@Sid1138 Excuse me, but could you tell me if what is told in the video is true, it us possible that light might even go back in time by -x in some directions and c+x in opposite directions? It still would be c to go both ways and we still would not know it since it would be impossible to notice or measure woudn't it?

@Abyss oh, I forgot. I am not saying the variance is constant or directional. What I am saying is there are a large number of ways that have nothing to do with round trip time to prove C is constant in any and all directions and locations. Note, there is some evidence (slim evidence) that C was different and in the distant past. But that’s for another discussion.

@Abyss nice reply and excellent questions. The video did not explicitly mention gravity. However gravity and light are tightly coupled. For example, the Schwarzschild radius is the radius where a mass turns into a black hole R = 2MG / c^2 Where R is the Schwarzschild radius, G is the universal gravitational constant, M is the mass under consideration, and c is the speed of light. If c is not constant then fast light could escape black holes. Since we do not see that, no fast light. As for general relativity, light is always the same speed. Gravitational fields just bends the light. Note, the Hubble telescope has photographed this effect on galactic scales. Look for gravitational lending online for some interesting pictures.

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.

@Cédrick Greenoak how do you verify that it's the same time on both devices?

@Lindorosso if we could send information with these entangled electrons, I wonder if we could ever "know" that entanglement happens at the same moment since al the observations or confirmations would be round trip to transfer the information. All the proofs and experiments about entanglement probably make the same assumption about C being the same in all directions.

quantum entanglement it can be use?

Dustin finally broke through the ice with his submarine. ;)

As someone who never even took physics in school I find this interesting. I actually assume there would be a difference due to us traveling through space. Light may find it easier to travel one direction than the other.

if the speed of light is just defined as the propagation rate of an electromagnetic wave, can’t we just rely on the equation maxwell used to relate it to the electric and magnetic constants for the one way speed of light (which is presumably independent of direction)?

Yeah we can...but still it would be a pure mathematical proof of one-way speed of light and this video only covers the experimental part.

Good point, I am surprised he didn't mention that. That said, for that reason, a constant speed in all directions is called for, until someone can show the permittivity and permeability vary, well, I think it's safe to say Einstein got it right.

I kinda of agree completely with Derek on this, although this had my brain buzzing at first. Also it reminded me how we do things or tend accept a conventional means till we don't doubt them while it kinda of affects the way think and learn.... really love the info and concept

You are a great educator. Thanks for this video. And maybe in fact this is the one things that ties everything together!

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.

The reason you never thought of it, is because it is nonsense click bait. If you were “intrigued” by it, then I feel very sorry for your physics students..

damn.

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Are you a shill? This puzzle has been circulating for years and it is just as stupid as it was originally. Either c can be affected by external conditions or it can't, but if it can, it certainly can not be altered to the degree indicated in these stupid puzzles.

See my series crushing atheist myths. I proved the big bang wrong, racist macro-evolution wrong, and quandumb wrong. Also: ice ages never existed, dinosaurs never existed.... but you guys don't question what you're taught, almost invariably. I get it... THe truth is not welcome.... to most of you. But maybe one of you cares.

I've been wondering about something along these lines while watching Star Trek. Does the concept of "stardates" make any sense if, as you say, the concept of simultaneity, considered across vast stretches of spacetime, may be absurd or unattainable?

Is it possible to subject two particles to quantum entanglement (call them "twins"), separate them 1km apart, shoot a beam of light at the twin 1km away and measure the change in the excitation state of the twin at the origin of the beam? As I understand it, the information ought to travel faster-than-light (if a delay exists).

@kungfreddie It is not the change of the spin but the collapse of the probability function of the spin. Quantum entanglement is instantaneous but it doesn’t transfer information.

@Loisel Loiselus ? I've always heard that the change in spin is instantaneous...

Sadly there is no way to send information faster than light. Quantum entanglement does not transfer information.

Love your videos. It's a great academic question. I assume you are only questioning the constant value of C and not the validity of E=MC Squared. If Einstein's equation is valid, and light travels at different speeds in different direction then damage from a nuclear weapon would be different in different directions from ground zero.

I really enjoyed this. It does bring up a lot of things to consider. It also means that there could be an inherent flaw in computing. Especially when it comes to synchronization over distances. The simple fact that two computers across town from each other could be getting their time from a NTP server centered between them and be out of sync. It would be impossible to know they are out of sync for the same reason that Mark and mission control where unaware. A very interesting 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.

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😂😂😂

😂

🤣🤣🤣

😂🤣😂. We always have that funny guy in every class who doesn’t care about anything and becomes the future billionaire

The speed of light is important because it shows up in Maxwell's equations (among other places). I believe that the best way to check for anisotropy is to formulate an anisotropic version of Maxwell's equations, and ask what experimental predictions it makes. And you can do the same thing for quantum mechanics. If it doesn't make any experimentally testable predictions, then we (OK, physicists) wouldn't care. If it, does, anisotropy could be ruled in or out. Has anybody done that? (I heard a talk once where somebody was suggesting that the phycsical constants may be different in different parts of the universe, but that was years ago, and I don't know if people think that's possible now.)

the kind of anisotropy suggested here would break many conservation laws.

I agree with everything, but with my limited knowledge I have one main challenge to it. This is that wave speed is equal to wavelength x frequency, so in order for the speed of light in one direction to be instantaneous, it's wavelength or frequency would have to be infinite. Furthermore, any difference in the speed of light in both directions could be found by observing the change in wavelength or frequency of the returning wave vs the initially projected wave. We would perceive a sort of red or blueshift in the lightwave. There is also no plausible way in which the wavelength or frequency of a light wave could be infinite. Let alone become infinite after reflection for no apparent reason. You're a smart guy so you've probably thought of this, but it seems like a fairly valid point. I'd love to hear your explanation as to why this isn't the case if it is in fact not the case.

any color shifting or wavelength shifting is based on c. therefore it would shift the same amount regardless of direction because you would actually be measuring a round trip. So let's say in one direction it were twice as fast as in the other, light would shift more per kph in the slower direction - therefore compensating for the speed difference.

Start the two clocks in the middle and transport the clocks and a person or device that can document the time of arrival on their clock to either end, then transport them both back to the middle. If the times documented at the ends are different, would you know relativity was affected differently based on direction, meaning light was traveling slower or faster in one direction?

you'd still be measuring the 2 way speed in this example. The clocks going one way and then back the opposite way to where they started

Yeah there has to be some reason that doesnt work, I was just wondering the same thing and went to look in the comments.

So, how about entangled electrons. Something that happens to one of them, simultaneously happens to the entangled particle. So if you hit one of them with a laser, you could see it being hit by observing the other particle. If you shine the laser at particle A from particle, and then shine the laser at particle B from particle As' position, you should be able to determine if light travels at the same speed in all directions.

There's definitely a major consensus that entanglement cannot be used to send information. You still have to take the measurement at each end, the entangled particle won't just let you know its pair particle has collapsed. also as @Matthew Cornelisse said the result is probabilistic for each observer anyway, so they have to communicate at light speed or slower in order to compare results, so we're back at square one measuring the two-way speed again

@Philip in this case it's not a matter of our technology but the rules of the Univers. So unless we are very wrong it's just completely impossible to use entanglent or any other method to send data faster then the speed of light.

@Rob Olde Agterhuis yes they are. But you don't send the message through the entangled particles. You use the entangled particles as a streem of random data for OTP encryption which is unbreakable.

@Matthew Cornelisse I’m not a physicist, just a chemical biologist. So I’m not sure what’s possible yet. But I’m sure it’ll be a possibility soon, the field is advancing quickly and quantum computing is advancing too. I have no doubt that you can couple some electrons in a quantum computer and get something out of it at some point.

@Philip doesn't work that way. There is no clever trick to send data through entanglement. You will only ever see randomness in results. There are useful features of entanglement but breaking the speed of cosality is not one of them.

If the speed of light were not the same in every direction, then wouldn't the cosmos look very different in different parts of the sky? For instance we would look in one direction and see early quasars and a warmer cosmic microwave background, and in the other direction see nothing but red dwarfs. Of course, the universe might not be isotropic, but if it isn't then we have bigger theoretical problems.

Exactly what I was thinking; though I think that only rules out extremes in the difference of one way c, right? It could still vary by just a smidge, I guess. Since the CMB we observe is fairly homogeneous, I feel like that would have to mean c is, too.

@Ripcord I don't think anyone really believes the speed of light differs in different directions, but Relativity implies there's no way to prove that, unlike in a Newtonian universe where time is absolute everywhere. In a relativistic universe, I think the combination of expansion and isotropism provide good empirical evidence but there's no local experiment you can perform. And if the universe turns out not to be as isotropic as we think it is, that makes the case even weaker.

@Thomas Horne you miss the major problem with the theory. The universe is expanding in all directions evenly (based on our perception). If light travelled differently in different directions that would mean catastrophic things for the universe, and would make the problem of what the universe really is a lot more complicated than it already is. Because you are basically saying, "no the universe doesn't look like it's expanding because the amount of light reaching us is equal on all sides, it looks like it's expanding because it literally is magically expanding." Just think about how dumb that sounds and try to still believe what this video is saying. Take some advice from a photonics graduate. The guy couldn't be more misinformed. If you are genuinely curious go study photonics too.

@Siddhant Kanoi no, they can't elaborate because they didn't think before they commented.

We don't know anything first-hand about the distant universe. We also don't know, with certainty, the behaviour of light that is a million years old. Maybe we need to get a distant probe to get closer (or farther) from the gravity-lensed supernova that we expect to see again in a few months? years?... and take measurements. Unless we can't synchronize our clocks. Uh oh.

"Why is there so much matter relative to anti matter" is kind of a crazy assumption, Veri. See the observable universe may be a corner of the universe as physically and geographically arbitrary to the centre f the ACTUAL universe as a terrestrial grain of sand is to the milky way, or much, much more arbitrary - and irrelevant to the greater sum. The asymmetry of antimatter is utterly unknowable until we have measured the ENTIRE universe, so maybe let's revisit this when you're uploaded to vertiasiumbot 5000 AD. We'll find that to the Planck, to a fraction of a Planck, the combined sum of anti matter and energy (using -E=-MC^2 and E=MC^2) is completely 0, of that I am sure. That's the only way something comes from nothing. I don't see a way around that.

could you use entangled pairs to measure the one way speed of light?

Idk, think about this. How do we know that the air it's self that the light has to travel through, doesn't change in density? Would that change the speed of the light getting to its objective? What about objects in the air? If not, then could we not time an image of light? Set up a flash light on one side, put a camera on the other side. Then time how long it takes for the light to show up on the camera.

Speed = Distance / Time. So, if gravity affects time/space (distance), how can we really measure speed? Wouldn't speed be so relativistic that it would be impossible to measure it? Doesn't the perception of speed depend on the observer? If one thinks about it, the human brain is always experiencing the past, never the true present (a moment where all matter and energy are probabilistically static), because of the "time" it takes to process electrical impulses. All the stimuli our brains perceive has already occurred.

Light: "My speed is immeasurable, and my time is ruined"

You got me

I think I did it: If we build a system of communicating vessels of the same size and both within the same distance of a source that pours a fluid in the system at a constant flow the two vessels would fill at the same speed, right? Even if the distance from the source is 1/2 Km. So if we put a reader at each vessel they would read the same level between them at any given time. We program the readers to start a clock when the level reach X and that would happen at the same time in each vessel. Also when the level reaches X one of the readers would activate a lazer, that would stop the other clock when it reached it.

corret

We dont know your time tho

@Mailcs06 there have been approximations of the “life expectancy” of a photon. If it does in fact degrade at all, after 100 trillion years, it would have experienced the passage of time. Just on a scale that’s experientially incomprehensible. Second possibility is that if 100 beings are moving at the speed of light they might experience a level of subtly in time that we aren’t aware of it. How much of a difference would it be moving 1/10 of a m/s slower and 1/5 m/s slower. They would likely experience a relative difference. Relative to us, it’s still functionally the speed of light. To them, not so much. Everything we know that is factual, is only approximately and currently so.

What about 1 clock connected to 2 sensors? The first sensor, when triggered, will complete a circuit starting the clock, and the second sensor will break the circuit stopping the clock. The laser would move in one direction, and the signals sent from the sensors to either complete or break the circuit can be perpendicular to the direction of the laser. Then you can turn the whole device around in different orientations to check for any fluctuations.

or just shoot 2 laser beams...

Couldn't you just do the fiber test, but use multiple lengths and forms as well as measuring the light whilst traveling in both directions? With enough varying data and repeatable results, you should be able to come to a very accurate conclusion on the general speed of light, as well as wether or not outside forces or directions have any influence. If I were to do that, I'd likely also want to test the same idea in a vacuum. I feel like the vacuum test would be arguably the most important measurement as much of our understanding of time and space outside of the earth is based on light that travels in the vacuum of space. Jusy my opinion and thoughts. Interesting video.

Since in the fiber optic cable the light leaves and returns at the same point, the amount light travels in any direction will perfectly cancle each other out making it a measurement of the two-way speed of light

I have a solution. Take two clocks at the same place and start both timers at the same time. Then move them apart so that each would travel the same distance in opposite directions. As soon as the distance goal (let’s say 0.5 km) is reached – stop the timer. Now you can compare both timers to see the diffrence in duration.

If the speed of light is faster in one direction, time dilation will be different in that direction as well, so your clocks are only synced if c is the same in both direction. (discussed at 10:45 I just realised)

I'll have to watch the video when I get back from work, but as to an instantaneous signal used to synchronize the clocks, do we know how fast the information from quantum entanglement travels? Does it, too, seem to propagate at the speed of light?

This channel always makes me feel smarter when I actually have basically learned nothing.

@Ujjawal Yadav What's more funny is how people are unaware that speed of light was discovered about 40000 years ago (earliest available writing is 8000 years old). It's in Rig Veda, one of the 4 vedas of sanatan dharm (Hinduism).

go to school. this video is very misinformed

Finding out that something is not known IS itself learning, or hopefully at least gaining curiosity for further learning. :)

without synchronizing the clocks, I think I found out a way of calculating the speed in one way. Please check my comment today.

Nothing in the universe can travel at the speed of light, they say, forgetful of the shadow's speed. Howard Nemerov (American poet)

Wouldn't we see a inconsistent red shifting on further away stars from different directions if C isn't the same? Perhaps that's a different case because red shifting due to the expansion of space seems to break the first thermodynamic law (might be wrong here)

Of course you would. This video is total BS..

Wait, but what about the CMB? If light would travel instantly in one direction, wouldn't we get an abrupt hole in the CMB? Given that the light that was emitted in the "instantaneous" direction would instantly zoom through the then existing universe.

@Cole Slayden But THEN it means the other "half of c" half of the universe IS showing what happened eons ago, and that just doesn't make sense to me. I haven't been able to find anything on the matter, and that's what's bothering me

This episode made me unsubscribe from Veritasium. This is beyond stupid.

The theory is that we would be seeing that in real time, meaning everything we observe there is actually there right now rather than eons ago like we think?

Brilliant thought. Now think of this. If the photon field is travelling at C , it does not experience time. To the photon which left the surface of a quasar across the observable universe, its journey arrived at the telescope at the same time it was emitted.

Ole Rømer's calculations of lightspeed were pretty amazing for 1675, he was one clever guy.

I love that all these guys are friends and all they care about is figuring stuff out, learning and showing us.

He should have called a quantum physics YouTuber like Matt O'Doud.

Maybe the real speed of light is the friends we meet along the way

@nik sullivan hahahaha lol

@Sonja Schellevis yeaaaa delete your comment and then play victim, ok

Perhaps, time is relative to our solar system. Let's say that the plane our solar system orbits the sun is the X and Y axis, and our sun orbits our black hole on the Z axis. With this concept, we may always record the same speed of light along the X and Y axis, but speed of light may be different along the z axis. I believe this would make the most sense as light gets trapped in a black hole so perhaps light itself is being pulled into our black hole and that force slows down the speed of light moving in the opposite direction. Here's my idea on how to measure speed of light in one direction: Step 1) As mentioned in the video, have nasa tell an astronaut on Mars to set their clock for a set time to match the time on earth (do this assuming the speed of light is the same in both directions). Step 2) Intentionally use an explosion set exactly in between the planets during a rendezvous and examine this event from humans with telescopes on both planets. Step 3) Write down the exact time this event was witnessed by both parties and compare times. P.S. doing this during different times of the year may also change the results, if both planets are moving in the same direction, this may provide false results during a rendezvous but accurate results while the planets are moving apart from each other.

I came to the same idea sorta. I was thinking with how he was talking about the message times from mars to earth. We could do a scaled down version where on earth set 2 digital stop watches at the same time on earth and send someone to space or the moon. You have a program coded to stop the stop watch when the person on the moon receives the message , and also need to stop earth stopwatch as soon as it was sent. I think you could duplicate it the other way with another 2 and see if they are the same. I believe this makes since I need someone to try and deebunk it.

Can't you use a material with high refractive index to pass light and signal the detector at light speed? Knowing the material and travel time we could add up to get the speed? I don't know if that counts as a one way speed. Or how about using a Laser on a semiconductor and comparing the momentum energy of the photon with the charge produced?

Yep. I have thought of that a lot. The true problem is that shooting light from one source will be different than the light that is changed by the reflector. It is obviously different. Perhaps the only true test is in shooting light far enough away that it takes time to reach the receiver. Distance. Also light will go through differences in atmosphere, etc… Nothing is ever exactly the same at any time.

Okay, I have an idea. What if we send 2 identical pulses of light? Both the light pulses travel in the same direction towards two identical clocks at adjacent distance same as the sources, but one clock is further away than the other. The difference between the clocks could tell us the speed of light. A - - - - - - - - - - - - - - - - - - - - - - - - - - -> B | A - - - - - - - - - - - - - - -> B' Here, the direction for each light pulse is the same. Similarly, we could let the clocks send a new pulse as soon as each of them receives the original pulse, but in the opposite direction. Could the differences in the clocks & distances between B and B' tell us the actual one-way speed of light?

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.

Honestly I'm more intrigued by how much delay the mirror is adding to the duration of the trip. Have we ever observed anything that could suggest the speed of light is different in each direction? Is there anything in the laws of the physics that could allow that? Does one half of the universe look older than the other? Have we ever launched a satellite, slowed down its clock to match its speed with clocks on the earth, and still it would end up out of sync by any amount of time even if it's just during one section of its orbit? How could this speed of light issue even work on a 3D space? Because all examples here were in one single dimension. How could the speed of light be different in 3 dimensions and still everything works as if c is a constant value?

we can start 2 clocks and walk in opposite directions for when the clock reaches 1 hour then we measure the distance between the two clocks and the starting point. if the distance is different then the speed of light is not the same in different directions if the distance is the same then the speed of light is the same

Is it possible to use a large gravitational force to bend the light in a circle and measure it that way? I'd think when a black hole can bend ligth it should be possible to make a perfect circle. I don't know if the same would be possible with a light conducter like glass fibers.

You had me at baseball. 💪🏻 But then you blew my mind. Well played, sir.

The concept of light reaching a infinite speed on the way back is such a cool idea

Kono Dio da

ZU WARUDO

@Karoshn damn that’s disheartening

@Totodile comment threads max out at 500 comments

Trying to find the speed of light so you can outrun it and save yourself I see

If I can measure the rotation of a planet from earth, then, can't I measure the time it takes to physically get there; and once I'm there also measure the time that planet takes to rotate--thus proving, by verification, the speed of "visible" rotation which directly relates to the speed of light?

Quantum entanglement and spooky action might give an ability to act as an instantaneous reactor if a pair of entangled particles are placed at a known distance. I believe light being known gravitational interaction would have different speeds.

To know if indeed light travels at different speeds, why not point two lights coming from opposite directions , at the same clock in between them? and activate those two lights by means of a rigid mass that one end moves instantaneously as the other. (Or something using entangled particles as the trigger since it’s instantaneous too)

If the speed of light is different in different directions, then there's a part of the sky where there are no red-shifted galaxies. Of course, that might be true if that inconsistancy in light speed in different directions is the same across the whole observable Universe, and if it isn't, my brain is overheating

"So someone has measured the speed of light...or have they?" Huge Vsauce moment right there

What's more funny is how people are unaware that speed of light was discovered about 40000 years ago (earliest available writing is 8000 years old). It's in Rig Veda, one of the 4 vedas of sanatan dharm (Hinduism).

without synchronizing the clocks, I think I found out a way of calculating the speed in one way. Please check my comment today.

Ha!

no we have only tried to gain a poiint of reference ie the >> 299*

@Shomex Shome You 're remarks are easy and good. But, light travels bringing informations, and as far we know once you break that limit information won't be carried away. From you're perspective classical physic is ok, but quantun physic would have you to be on a superposition to be right or wrong. So unless you can keep your superposition argument collapses.

Accounting for the gravitational affects on space/time and thus use extremely powerful magnetic fields that can bend light through multiple fields until bending the initial photon around in a horse shoe bend directly back to the originating single clock detector from which the photon fist was emitted , will isolate the distance speed measurement to only the one clock , eliminating the non-synchronized behavior of two separated clocks.

What if you had a laser, a mirror, and a timer, situated on a right triangle, where lines A and B are equally long, let's say half a kilometre each, such that the laser and the timer are on opposite sides of line C? The laser is pointed down line A towards the mirror which reflects the laser onto line B towards the timer, which will stop when it senses the laser. The button that fires the laser is also the one that starts the timer, and this signal pulse telling the timer to start travels along line C. This in theory should produce the result of the timer counting the distance it took the light to travel C-(A+B), or roughly 292.993 metres. If there's any statistically significant deviation from that, then it might be possible to know that _c_ being a universal constant is false, at the very least. I'm almost positive I missed a few issues with that; any thoughts?

Hey Veritasium , why don't we put two photons(that can annihilate each other) in the same tube one at the start of the tube one at the end of the tube (a really long one ) and then we put two cameras at the ends of the tube. So the theory is if light goes the same speed both ways then their redshift would be negligable and if the speed of light is not the same then the one of the photons would redshift more (because the distance travelled is greater) and they would not annihilatr and we would see the light on both of cameras

How about using quantum entanglement to sync the two clocks? Changing one particle, changes the other instantaneously - regardless of distance (no time dilation).

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?

@hedare Many people make this mistake. Redshift has nothing to do with how fast light travels; it only depends on distance traveled.

@Science Revolution general relativity is wrong for only one reason. It doesn't work in conjunction with quantum mechanics. Everythng else it predicts holds as it produces accurate predictions. Let's see all the math you have to make accurate predictions on your model. You have nothing but supposition and logical fallacies. Give me the math for the relativistic correction factor of gps satellites then. Cause according to your view we don't need one.

Question? Is there such a thing as the speed of dark? In principle, shadows can move faster than the speed of light. ... If the shadow is large enough, it could move across the surface faster than light. This is an illusion that light travels faster than the speed of darkness since darkness is all around the light and it is still agreed that no physical object can travel faster — since light and darkness has no mass. Hey, how do you find a blind man on a nude beach? youu know, it's not hard. The scientists of today think deeply instead of clearly. One must be sane to think clearly, but one can think deeply and be quite insane. If you want to find the secrets of the universe, think in terms of energy, frequency, and vibration. Today’s scientists have substituted mathematics for experiments, and they wander off through equation after equation and eventually build a structure which has no relation to reality. If we only knew the magnificence of the 3, 6, and 9, then we would have the key to the universe and the understanding to view the model were in. But to believe in Space – The Impossible Frontier! That's not a blind man, it is just too hard.love this channel. Space – The Impossible Frontier! https://www.youtube.com/watch?v=VFEdPCJTwSs&list=UUXIovaBdnA4UHdd-TZ-MqRg&index=5

@Nocare Awesome, double shift enter!! Thanks for making me think for the first time in years lol and good luck with your ambitions in global robot domination :)

Can't you use two synchronized clocks 1 KM apart and instead of measuring 1 beam of light traveling in 1 direction, you use 2 beams of light aimed in opposite directions, as in A going to B and B going to A at the same time, and the clocks stop when the beam of light aimed at them is detected? Assuming, of course, both beams are fired simultaneously. Assuming the signal to fire the light starts from the same spot, half-way between both clocks, to make sure we could remove the theoretical "directional" speed of light, if it were to move at different speeds in different directions, you would also need 2 additional synchronized clocks (A' and B') with respect to the actual time of day, which would have to log the time that the signal to launch the beam of light reached the respective clock? Assuming A is 1KM away from B, and the starting signal is fired half-way between each, if the secondary clocks at A' and B' have different firing times for the light beams, we could use the results to prove or disprove a theoretical difference of speed for light in different directions? WE could go further and add in 2-6 extra beams of light in different cardinal directions: A-B could be East-West, but C-D is N-S, and then more in NW-SE and so on, to further verify that it is at least the same, or different, in different directions. Of course, I'm assuming you didn't mention this because this was already thought of and debunked, presumably due to the impossibility of actually verifying that two clocks that are synchronized, even from an equal distance, may not truly be synchronized due to the time a signal would take them to reach them might be different in different directions. Mind confirming this?

Wouldn’t it work if using the same clocks we shoot the light from both ends at different time and calculate? If not, then why not? Just a thought

What if we measured the red shifting of light from stars at some distance away from earth on one side of the universe to the other? If light is different speeds wouldn’t light from one side be redshifted, while the other isn’t?

@J Block oh that makes sense

any color shifting or wavelength shifting is based on c. therefore it would shift the same amount regardless of direction because you would actually be measuring a round trip. So let's say in one direction it were twice as fast as in the other, light would shift more per kph in the slower direction - therefore compensating for the speed difference.

Let’s imagine a rod of length 1 km with two pointers of equal lengths at the end pointing downwards Initially the rod is at some upward distance from clocks so are the pointers Drop the rod the clocks start once the pointers touch the clock they are in sync Now through the light beam (clocks are of type that stop the moment they detect the light) you can now measure the one way speed

Problem is, if the clocks are both on the receiving end, you can't track when the light left the origin side, preventing you from measuring the travel time. And if one clock is on each end, the clocks did not have the same movement and speeds prior to the test, meaning they are no longer synced.

that probably wouldnt be very practical

I will say it's pretty impressive that Einstein realized that this was a significant issue before he started to tackle relativity.

I would like to add that Mr Muller is not right for measurement of speed of light moving in one direction. The speed of light was measured at first, by two astronomers Ole Roemer in 1676 and James Bradley. Both astronomical observations measures the speed of light moving in only one direction. Roemer observes the eclipses of Jupier moon Io, and the observed orbital period of Io is getting slower if the Earth is moving away from Jupiter or getting faster if the Earth is moving closer to Jupiter. Stellar aberration of light observed by James Bradley in 1728, all stars makes a small ellipses during the year in the same direction as Earth orbital movement, clockwise if you look at the North pole. So astronomical observations are available long time ago and the same speed of light in all direction from everywhere is an astronomical observation fact, not a convention.

Impressive!! Is there another way to describe that man?

@Ophir Averbuch — So that means it was not *AFTER* he tackled relativity, right? It was part of what he thought about on the way to writing the theory. Thus, "before".

The paper Derek quotes from is the one where Einstein laid down special relativity for the first time, so it wasn't before he started tackle relativity

@Michael Frankel Why shouldn't it be?

Use two entangled photons from a source and send them into a buffer which keeps the consistency of both superpostioned photons in a two clock setup. Rread out the polarisation of photon A at clock A and instantanous (based upon the speed indipendence of superpositional information of entangled quantum particles) Photon B shows it's entagled state which triggers clock B. For example the polarisation beeing the switch itself in conjunction with a polarisation filter. Instantanous clock synchronisation.

Quantum entanglement and spooky action might give an ability to act as an instantaneous reactor if a pair of entangled particles are placed at a known distance. Light has been accepted to have a gravitational interaction so it should have different speeds.

Well, what if we sent a device on the moon capable of detecting signals sent from earth and with it's own clock? Sure, there would variation due to relativity but that would be a more negligible discrepancy on a distance of that scale. We'd certainly know whether or not the speed of light is closer to c or c/2

couldnt you solve for the different speeds in each direction by simply having 2 tests where one way the distance is the same, and on the way back the distance is different? if the difference in time doesnt match up to the current speed of light, then that proves that it has a different speed in separate directions

I love how he always considers variables to problems that most people would never even think of in the first place. Like the possibility that light, or a signal, may change speed based on direction. Mind blown

He over complicated things it seems incredibly easy to measure one way light speed

This may be exiting, but one should also consiider the Electromagnetic Theory by Maxwell !

@Gordon Seal measuring it going in different directions is still a two way trip, it goes from the source to where it hits something, and then to the camera after reflecting. you just watched a video that explains this in the middle of it. it is only a convention not a hypothosis or theory, and the universe doesnt make sense alot of the time anyway so thats not really a good point. i heard a saying once that dums it up pretty well "the first thing you think of isnt always the right answer". it made sense that the earth was flat or the center of the universe before we had ways to measure why thats not the case, it could be the same here.

@CGN we dont know if it does or not, thats the cool part. just as veritasium explained we have only measured the 2 way speed of light, not the one way trip.

@Tim Bordasch Because A) it makes no sense and B) it would be measurable by recording light going into different directions and C) it would probably break the universe on a fundamental level, if light just behaved totally unexpectable.

what about starting a third clock that is designed to plug in to the sensors so that the sensor clocks sync up with it. It can be done one at a time so that even if there is latency in the sync, it would be the same on both the sensor clocks allowing them to be perfectly matched.

what if you test multiple angles? Lets say you bounce light off of one mirror to another mirror and back to the source and calculated time. If you changed the initial angle as well as the placement of the other 2 objects and tested again, any different results should show if a particular angle takes longer than another one right?

Derek - I'm late to the party on this one but I have a thought on this and I don't see why it wouldn't work. Why not eliminate one of the possibilities by forcing an outcome? For instance, if the issue is that we don't know if the speed of light in one direction is C and C on the return, or C/2 in one direction and infinite on the return ... then basic troubleshooting says we should eliminate a possibility by forcing the "infinite speed on the return trip" result by tying the detector not to a clock, but to a measurement device of a single entangled particle. It's entangled partner, we keep with us back at the laser emitter. In this experiment, wouldn't we have eliminated the ambiguity of relativistic effects by rigging the collapse of the entangle particles' wave functions as a kind of ... FTL stop watch? All we'd be required to do is wait for our entangled particle to collapse out of superposition. Then, based on our own clock, we would know if that collapse occurred at C or C/2 regardless of relativistic effects at the detector because we've insured an "instant" return speed either way. Right?

Is it actually possible for something to be “instantaneous” because if there is distance, there has to be time.

This certainly has interesting legal implications for speeding tickets based on laser detectors (previously mistakenly referred to as "radar guns".)

@nobodyofnaught2 Got it, thanks.

-you were travelling at the speed of light -no, i was travelling c/2 only, you see, light travels in one direction the reflects instantly because... -oh okay, you are free to go dumb cops, amirigt?

@itSp4x Does that depend if ALL the photons are returned? The material that the light "hits" may remove or could be made to remove the first photon to hit it?

@Rob Larrikin he explained that at 10:44

At 2:41 the idea of synchronizing the two clocks next to each other and then moving one to the other end was struck down because the moved clock would tick slower than the other relative to stationary observers. How about moving both clocks - the left one towards the left; the right one towards the right, at the same speed, until they are properly spaced? That would remove the problem and they would both still be synchronized.

love the videos, going to try to get my children to watch :) thank you

What if you setup a mirror on Mars and shot a Lazer at it and when the light hit the mirror you would,at that exact moment, shot a Lazer back to earth, wouldn't you be able to measure the 2 separate beams as they returned to earth? If the light coming back from the mirror was instantaneous then it would be ahead of the light that was shot back from Mars

Oh, and photons experience no time apparently. If this is indeed true, light would always travel at the cosmic speed limit. Light would move at the same speed no matter how dim or bright it was. Photons are extra energy expelled off a neutron¿. Sorry, I've had a couple... I'm getting house projects done and listening to this on my 1701-D Bluetooth speaker. It's awesome.

A possile solution is that 2 messages will be sent to earth at different distances but coming from the same direction, if earth receives it at the same time, this would mean that the speed of light is instantaneous on that direction, however the problem again is how we get the signals to be sent in sync to earth.

This was brilliant. Thank you for this. Never stop giving us such videos and theories,etc.

You should do an episode on how the constructive and destructive interference of voids in soap bubbles mimic that of the universe's own super structure. i.e. voids and filaments.

If there was a much of a difference wouldn’t you expect that when you looked in certain directions, you could see that galaxies in general looked younger than ones in the opposite direction?

I was going to say no, because they are also affected by time dilation, just like in the example of slowly moving the clocks. But if they are moved apart from one another through the expansion of space, that doesn't really apply right? If so, could we in theory use this to separate two timers without being affected by time dilation too?

Today's technology may (does) provide a way to fully synchronize the clocks. It might also help resolve whether there is speed change related to direction of travel, which is allusion of a wave component. Great job

Two clocks connected by a wire to synchronise, with the detector for the second clock behind a polarized mirror. When A sends a pulse, you would expect A - B to be 0 since the pulse to synchronise the clocks would travel at the speed of light. A - B - A would be the 2 way speed. Without moving the clocks, sever the connection between the clocks and take half of the time it took the pulse to get from A - B - A from clock B. If A - B remains 0, then the speed light 1 way is the same as the speed of light 2 ways.

If the speed of light was different in different directions, wouldn't one side of the universe look younger than another side?

​@Catfish Billy 3.7 There are ways to determine relative amounts of energy by different star types. Stars which are older tend to collapse into white dwarfs or supernova while some smaller stars known as white dwarfs can burn for much longer. I would expect an older "direction" of the universe to have more of these types on being observed. You might also expect that one direction of the universe (that with faster light speeds) would have less constant microwave background due to more CMB being redshifted out of detectable spectrums

How exactly do you accurately determine what is a “young” universe compared to an “older” universe?

It would, but you wouldnt know if which side is younger or if there's even a difference at all

As explained in the video it would still all even out because physics and mathematics do a great job of explaining stuff but also not explaining anything at all at the very same time.

@Planet Earth After reading my comment again I have added a footnote as i think it was not getting the point across correctly. I assume them "true" for now... they most likely arent but they are the best we have.

Could you program two clocks to start in response to a sound and stop in response to the light being sensed. Considering we know the speed of sound, origin of the sound, and distance to each clock.

Why don’t we measure the 3 way speed of light? That way, if we can calculate that 2c/2 is equal to 3c/3, then we know that c is constant in all directions. If 2c/2 is not equal to 3c/3, then we know c isn’t constant in all directions. Right?

try having 2 quantumly entangled particles that change when a photon hits then put them in a perfect vacuum and have one set up to a timer that stops instantly once the particle changes then fire your photon down the pipe and the instant the particle gets hit the quantum state changes and the other particle attached to the clock changes stopping the clock

I watched videos on time dilation which seem to suggest it’s not related to the speed of light but to the shape of space time. So the clocks being synchronised in the middle of the experiment and slowly moved away shouldn’t be affected by not knowing the speed of light. Rather by the different directions they take through space time.

This is an almost entirely uneducated thought: if the speed of light were any other speed than that as we commonly define, would not both the red- and blue-shifting of light be significantly increased and reduced in the preferred and nonpreferred directions? Also, if light were to travel slower, then it would stand to reason that black holes would have a larger event horizon for light - since the speed of light would be too low to escape its gravity well; so would we not see larger black holes in one direction, and smaller in another? If it were instantaneous, then I would imagine that we would basically see near-naked singularities in the optimal direction. Tied to that point, would we also not see a larger portion of the visible universe in one direction than the other? Assuming that the preferred direction is just a single direction, and any amount of deviation is a standard amount of a reduction in the speed of light until you reach the opposite direction .. we would see ourselves off-center to the visible bubble of our universe. If we only measured by time, then we would never know - but we could surely 'sample' the occurrence of stars visible in one direction vs another and see an almost impossible result of near infinite stars in one direction, and half the standard amount in the other. Final thought. it is considered that every point in the universe is the center of the universe since expansion is happening everywhere evenly (as far as we/i know) but as a result, we can measure the CMB to be approximately equidistant in all directions and of approximately equal strength. If there were a preferred direction for the speed of light, would there not be a black-spot of CMB where there no longer exists any radiation to emit in our direction? My understanding is that the CMB is eternally being stretched and shifted so it will always be seen, just at longer and longer wavelengths. If it were to travel instantly, then from all points in the preferred direction, no shifting could occur, and no further emission would be possible unless the universe were truly infinite in at least that direction. But then, infinite speed over infinite distance ... would that be undefined (10pm post-pizza math fails me) All of these are off the top of my head, and I have done no research. I don't intend to be an armchair physicist, but I am curious as to the answers, so please feel free to correct anything i'm wrong about (probably all of it).

@Steve Different colors travel at the same speed (in vacuum), they just have different wavelengths. It doesn't matter which color we choose. It does not even matter if it is visible for us or not.

@Steve I believe I am right in saying that the classical 'speed of light' is constant for all forms of light / EM radiation. The colour of visible light is simply a small difference in the wavelength of light which is detected by light-sensing receptors in the eye that can be stimulated by a specific wavelength of light. I think you may be confused on this because of red-shifting and blue-shifting. These terms refer to light that has had to travel over vast interstellar distances while the universe was/is expanding all around, or when the subject emitting the light is moving an appreciable speed in relation to the speed of light towards us. This stretching or shrinking affects the wavelength of the light, but does not change its speed. I think it does get more complicated when it comes to 'frames of reference' and such, but I think that is beyond me to be able to effectively cliff-note and explain. I hope that helps - and I hope i've got the basics right.

I also had the same thought WRT redshifting and blueshifting - the doppler equation replies on the speed of wave propagation, so if the propagation differed by direction then the doppler effect would differ by direction and would be immediately observable... but maybe the assumption about wave speed symmetry is built into the doppler equation? WRT black holes - event horizons are already weird, even if we were in a position to observe one directly... im not we can use that as a starting point for proving the symmetry of light speed. your point about the visible universe kinda makes sense - although I'm not super familiar with it so perhaps we're making some assumptions about how far away things are based on assuming symmetry of speed of light.

So, in one direction cosmic background radiation may have been emitted only moments ago while in the opposite direction a few trillion years ago. Suddenly the universe seem both much older and much younger than I thought.

This is a fundamental misunderstanding many people make on how light doesn't escape blackholes, you're assuming that it is the gravity that the speed of light cant escape. But it is in fact (well the suggested science at least) that blackholes warp spacetime so much that other directions stop existing and the only direction that exists is towards to the middle of the blackhole.

Maybe you should spend some time looking at two: i.e. instead of one direction and the opposite, vary it continuously around a point. Would the one-way speed vary continuously with the angle?

I don’t know how you could make this into a doable experiment, but if you put a giant mirror in a distant galaxy, and the one way speed of light was different than the two way speed, couldn’t you make that observable difference by examining our planet’s apparent age compared to that distant galaxy’s

10:34 Hold on right there, what that has to do with the GPS assuming the speed of light is the same in every direction? I might missed something because english is not my primary language, but the way I see it you were heading to a very interesting point that would prove that C is the same in every direction and returned to the clock synchronization problem. The point is, how GPS would even work if the speed of light can change with direction? You need at least 3 satellites to do the trigonometry necessary to calculate your coordinates, all assuming the one-way speed of each signal is exactly c, so, if just one of the signals arrives you faster or slower than C, I assume the math wouldn't work so the resulting coordinates would be different than your actual coordinates.

Shine a laser from both planets for a set amount of time starting and stopping at the same time (as set by Einstein’s standard) and then look at the length of the beam from your perspective and if there is a difference then you could prove c is not constant in all directions. Just like a video I saw saying distance is also based on relativity (something about a ladder that is too long for a shed can fit if it moves faster) so if the light was moving faster in one direction it’s beam would appear shorter. But if it’s for a set duration it should work as a test. What do you think?

@Bob li "as set by Einstein's standards" this is not to put them at the same time but to simultaneously test whether the durations (length) of the laser beam would be different (which they shouldn't be) duration of time wouldn't change in either of the potential universes but it would if one was moving faster than the other (although I now realize this may be true of physical objects but not light so you can substitute a near light speed object for the beam of light in this scenario)

How do you "Shine a laser from both planets for a set amount of time *starting and stopping at the same time*" when it states in the video that it is impossible? If you try to carry a clock then shine the laser at the set time, then time dilation will be a problem. If you try to sync the clock on the other planet, it may take different amounts of time to reach you depending on the one-way speed of light.

Me a smol brain: light travels at 1 lightyear per year. edit: turns out, this aint smol brain; this is big brain

I have the greatest idea of all time you know the video said where when earth got mail from mars saying its 12:00 they know it takes 20 minutes so it will be 12:20 but on earth its 12:40 cant we just say it these was send at you in 12:00 so in 20 mins it goes to you and it will be 12:40 for us so put that time. then it will same time in earth as the time said on the clock on mars.

THIS IS BIG BRAIN. I NEED MORE VERTIASIUM IN MY BODY!!

without synchronizing the clocks, I think I found out a way of calculating the speed in one way. Please check my comment today.

Nothing in the universe can travel at the speed of light, they say, forgetful of the shadow's speed. Howard Nemerov (American poet)

I just like that the guy on Mars is called Mark, and Mark (iplier) wants to go to space

This was very interesting! IT got me to think about this; What if you use two clocks Who starts at zero and is started at the same point and time, then move them apart at a equal constant speed in each direction not measured as speed over ground with a speedometer, but for example with a rope that is wining up at the same spool in the middle with a wheel in both ends the rope is going through and back to the clock. Then when both clocks has moved 1km from starting point they stop. Then compare the time on both. If they are the same, isn't that a proof that time is equal in both directions? And doesn't that prove that the light also moves at the same speed in both directions since time is the relative part that defines the speed of the light? 🤔

@Jack Berrien I meant that you could stop the clocks when both has reach the end Who would be at the same time according to the midpoint. And then write down the results of each clock on a paper to compare the time the clocks has stopped at. The clocks could each have an onboard endpoint-Switch to stop itself when it reaches the end so the time it used is showing static. (stop-watch). Wouldn't that be possible? 😄

This is a good idea, but the problem here is that in order to compare the two times you will either have to move them back together, thereby undoing the possible effects of time dilation in different directions or send some sort of signal back to yourself, which would also go in the opposite direction at the speed of light, undoing what you had done by moving the clocks apart.

I'm not a physicist but I watch enough StarTalk, you can't have equal amount of matter to antimatter. This is what happened at the beginning of the universe and had it been equal. All matter would have been wiped out. You have to have a little bit more so it essentially beats out the antimatter and you get the universe we live in

I have a thought on how we could definitively measure time, while answering the question of light traveling different speeds in different directions. The only catch, is it involves using quantum entanglement. If we could find two particles that were entangled together, then we could use the original earth to mars message. "This message was sent at exactly 12:00". The person on mars would then set his clock once he received the message, and used the einstein equation to set his clock. Step 2 of this experiment would be the understanding that at exactly 1:00 earth time, the entangled particle would be "moved". The person on mars would then check his watch to see what time it was for him when his entangled particle moved. If there is a difference in time, then we would know light traveled from mars to earth faster than earth to mars.

@Armin Lutz for some reason or another the last reply you left will not show up and it is literally taking over my life lol. All i can see is what shows in my notifications and it stops at "i dug a little deeper and here's what i found". I cant read anything beyond that lol. Would you be able to try posting again? I really think i could be on to a legitimate way to measure the speed of light and if we partnered together, the next nobel prize shall be ours. But adding to it, i have always thought that time has a direction. Not in the sense of "moving forward in time" but a physical presence and direction. If this were the case, and time was a physical dimension that interacts with all other matter in some way, then with proper technology we could manipulate it. Finding the speed and direction would be a start. Ive been doing a very long term experiment where when i feel like it is one of those days that "time just seems to fly by" i put a check on the date. Put an x on the dates where "time just seems to drag and drag". Once i get enough points of data to make a legitimate graph of some sort, i want to check the positions of major celestial bodies in space relative to Earth (i.e. Jupiter, the Sun, Saturn, maybe even Andromeda?) And see if there is a correlation between the position of large bodies of matter and the "feeling of the speed of time". That was my original thought on figuring out the "direction" of flow of time. Picturing it like a river, where time is the water and we are "rocks", if the sun was directly upstream of us, and time had to flow around and collapse back in, it would hypothetically be traveling faster to catch back up to equilibrium. Where as if we were off to the side or in the "wake" of time flowing around, perhaps it would be moving slower as it lost energy changing direction? I dont know, my curious thoughts 😬

I may be wrong, i am not a career scientist in any stretch of the imagination. However, if i recall my last deep dive into the realm of quantum mechanics, entangled particles experience the reactions instantaneously. They do not "send and receive" information back and forth, they are purely bound together regardless of the distance they are separated, be it light years, and what one feels, the other does as well. Unless new light has been shed on this topic that i have not learned yet, that is how i remember them behaving before. One of the many ways the quantum realm defies the laws of physics in the macro world.

This still wouldnt work, because the transmission of information in any way cannot be faster than light. Even for entangled particles the time the second particle "knows" about the "movement" of the first is bound to the one way speed of light in that direction which could still not be noticed due to the error already made by the synchronization of the clocks befor that. In terms of "information" there wouldnt be a difference between this and sending a message. And both suffer from the same problem.

just measure the decay of a particle with a short half life or something going two different directions with a constant acceleration in both directions. That way, you can find if the decay on one particle matches the other. Or something

If light traveled instantaneously from one direction, but 2C in the other, wouldn't the universe look very different depending on the direction of the observation? Wouldn't one edge of the observable universe look very mature, as it does locally today, and the other edge look primordial as it did billions of years ago?

@ICader you kind of answered your own question. If the universe is moving in a direction at some fraction of the speed of light. It could effect the speed of light.

@ICader no but the laws of physics can dictate "flowrate" it is entirely possible the fabric of space ( the gluonfield) to only allow light to flow freely in one direction and not the other not dissimilar to a Tesla valve.

@1smallstep Would the center of the universe be where the Big Bang happened? If the Big Bang was the expansion of a point singularity, does it make sense to say that it happened everywhere? (Google ``where did the big bang happen?'') Then isn't everywhere the center of the universe?

@ICader If wonder if the speed of light would be different on a planet where a secend( to those that might live there) Is not the same as our 1 second of time. Maybe they don't measure time in seconds ,minutes and hours like we do.

It would be a disco world with instantenous speed😁🤗✌️

Could you synchronize the clocks with an audible programming device, then adjust for the known speed of sound?

What about doing the mars synchronization with two different sets of clocks. Do one set as described in this video, then do the second set when mars is “On the other side” and see if there’s any difference. If the time is 1/2 C one way and instant the other way, mars would get the second “Sent at 12:00” message when their first clock says it’s still 12:00.

What if it leaves a little trail, like an imprint or a memory that it uses to fast travel back. Like it's own fiber optic cable.

What about having two clocks that have two electrons that are in quantum coupling, have them far apart, then you can start the clocks at the same time, no signal travel time?