Technically light can't be measured in one direction. Every time we have measured light it's been going in two directions, going one way than coming back. Einstein wrote about this long ago, he mentioned that light wouldn't be the same speed going in one direction than coming back. Veritasium made a video on this very issue
This reminds me of the Quote by Sir Terry Pratchett: "Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it."
One of the best videos of TIFO I have seen, I can't wait for you to tackle other physics topics in the same funny yet accurate matter (I should know I am a physicist). Very well written and delivered as always!
The GPS satellites travel at 14 million meter/HOUR, not per second. It would be quite a feat if we managed to get satellites to a speed of about 5% the speed of light ;)
\(^_^)/ U seem to know your stuff... If as he says at about 19:38 ish, that we would APPEAR to slow down, at near the speed of light, I always assumed that we would not notice it. Like in the twin paradox, neither would FEEL like their day to day life had sped up or slowed down? One would not feel like he was moving in ffw?
@@noahway13 That’s the general idea. This is even observed in certain unstable particles, as they’re able to travel much further than their half-life would suggest, because they’re experiencing slowed time.
DJ Cummerbund with yet another banger! I've watched a few of these types of mashes from several other artists on here and I gotta say this guy has the most spot on mixes of all. Beats all smoothly locked together, all pitches perfectly matched, seamless vocal transitions, each mix sounding like it was written as one song start to finish, well done good sir, well done!
The way I heard that story before was that James Clarke Maxwell calculated the speed of propagation of electromagnetic wave and because it was pretty much spot on the experimental measurements of value of light he surmised that visible light is indeed a form of EM radiation. Simon, did you do ADR in the bathroom?
I'm thinking Einstein must have been pleased to find out about the Lorentz-Fitzgerald transformation since it would have followed from his thought experiment. I also didn't realize that Galilean relativity played such a vital role for him (and is still valid).
as i sit here on the toilet besides the massive amount of energy I contain, there is something else that is about to be released and uncontained. Thanks for the vid Simon, always a good watch.
Light (or any electromagnetic radiation) is weird stuff. If you wiggle the electric field of nothingness, that wiggles the magnetic field of nothingness, which wiggles the electric field of nothingness, and thus the wiggle propagates forth through the nothingness. c depends on how fast those wiggles can wiggle each other.
I was indeed wondering, where and how did we originally devise or calculate the speed of Light; Perhaps more accurately called "the speed of Causality"
As a man of exquisite passion within radiology profession (CT Technologist), with a good knowledge of EM waves, XRay creation, photon behavior, etc, etc, etc, very good job.
One interesting side note, if Einstein is right then we can't know the speed of light with absolute certainty. The best we can do is measure the speed of a round-trip, light emitting from a source, striking a reflective object like a mirror, and returning to the point of origin. The reason why we couldn't measure the speed of light in one direction is to do so we'd need two perfectly synchronised clocks, one at the source and one at the destination, and that would require us to be able to communicate between the source and the destination instantaneously, which is impossible thanks to the speed of light being finite (in a round trip, I'll get back to that later). or it would require us to synchronise the clocks in one place, then move one of them, but because of time-dilation the instant we start moving one of the clocks, it will go out of synch with the other. As previously stated, we can measure the round-trip of light with extremely high precision, but that doesn't guarantee that the speed of light is always the same in all directions. It could be, for example, that the speed of the light on the out-bound leg is 1/2 the accepted figure for the speed of light, and that on the return leg its speed is infinite. That would give a round trip that matches the accepted figure for the speed of light, but we would have no way of knowing for sure that the light was always travelling at that speed for its entire journey. Intuitively, it would seem that the speed of light should be a universal constant in all directions, but it's been demonstrated that the laws of physics don't operate in an intuitive way more than once (for example, the weight of an object has nothing to do with how fast it will fall, though intuitively you'd think that heavy objects would fall faster than light ones). There is no observation you could make or no experiment you could conduct that would prove one way or the other whether the speed of light remains constant.
Fundamental flaws in physics: - Time = "what the clock reads" - Gravity = General Relativity explains what it is (but actually 100% doesn't) - Due to aforementioned misunderstanding of time: wave-particle duality appears to be a 'principle'. Likely more an aberration/flawed measurement based around a flawed base unit (time).
Love the format of your programs. The difficulty I have with the twin dilemma is that it assumes a zero reference. Assume two ships in deep space approaching each other at nearly the speed of light. Which one is moving, and which one is standing still? There must be a universal reference for this to work.
Note to the writer: It would be more useful to talk about time dilation in units of x microseconds per an explicit unit of time. I'm sure physicists have a unitary standard, like microseconds per second, but those of us who are not deeply immersed in the field will not necessarily be aware of this convention.
I just had an interesting thought. I don't know much about the actual science of black holes but the effects of approaching light speed are remarkably similar to those of a black hole. You have the spaghettification. You have dramatic increase of mass and time dilation. It almost sounds like when a star collapses into a singularity, all that energy is transferred into acceleration and the singularity reaching near or at light speed is ergo reaching near or at infinite mass, is what creates the black hole. Once again I only know so much about the actual science so it's all speculation, but cosmic coincidences only happen so often.
In the past, we had the duration of the "second" and tried to measure how much distance it travelled. Nowadays we have the "distance" of light travelled, and we chose a whole number. Now the duration of the "second" itself, is measured by how much "distance" light travels. EXACTLY (whole number) 299 792 458 Metres. Because the Earth does not orbit exactly on time, we chose distance as the better measure of things.
What about the time dialation/slowing effect when observing light arriving at the suface of a gravity object, and/or observing light emitted from at gravity object into vacuum? How is the measured speed of light affected?
I thought as much too; there do seem to be a few typos/errors in the script; its 14,000 km/HOUR, or 14 million meters per hour, only 3600 times faster than said. In due fairness, he recited speeds in "per second" many, many times in a single speech so whether the script had the error or he just misspoke is a job for the editor to slap in an on-screen annotation "Woops I meant to say per hour here" (EDIT: I even wrote 'per second' instead, supporting my hypothesis! Oops)
All light. Any massless particles, really. They must be massless to travel at that speed. Otherwise it would require an infinite amount of energy. Also, field perturbations, such as gravitational waves. The only “thing” I can think of that’s faster is the expansion of the universe.
@@BDB78 Since the expansion of the universe is an observed effect, not an object, it doesn't violate causality for its value of apparent motion to be greater than the speed of light. We could probably come up with a lot of "things" that are faster than the speed of light. If I point my finger at a star, and we define that point in space as the distance from my finger in that direction, and then quickly move my finger somewhere else in the sky, that 'finger point' moved faster than the speed of light at that distance. But the finger point isn't a physical object, and the expansion of the universe is just an observed effect from a huge universe full of tiny changing values.
We humans are made out of matter and all matter contains atomically bound energy. There's no way we have to tap that energy though. Only certain radioactive isotopes can make atomic energy. Which we humans do not possess. If you did you'd die quickly. It's a fairly popular assassination technique in certain circles to inject victims with radioactive isotopes. They usually use Polonium-210.
Interestingly, we are only "guessing" that the speed of light is c in all directions, due to it being the information speed limit of the universe its possible that it is 2c in one direction and instant in the opposite. All we know is that light makes a round trip at an avg speed of c
Actually, all we know is c-square is constant , its square root is an absolute value independent of direction. This is because "c" comes from the two-way wave equation ( a second-order linear partial differential equation) not a single one-way wave equation. Note "c" is a scalar value of the two-way wave equation so it does not make sense to ask what the direction of a scalar value is, its undefined. So the best or worst you could say is that its speed in a direction can be anything you want or nothing at all.
If we are looking back 13.5 Billion years with telescopes Today... then I wonder what has happened to all those Planets Suns and Galaxies that are all the way out over there since then. - #Universe
Time does not dilate and that’s been proven in quantum mechanics. Simon only explained the first half of the double slit experiment. The second half shows how the wave interference patter will go away depending on if the experiment was observed. See time does not dilate because it’s constant across all space. We know this because atoms would literally tear them selfs apart if it wasn’t constant. The speed of light (and all energy) changes when observed like with the double split experiment because it’s operating on a higher dimension than can be observed. The reason so many people including scientists believe that time can dilate is the super accurate clocks use lasers to keep time. Thus the change in the behavior of light is uniform leading people to think time was the only variable that could change. When in reality it’s the speed of light that is shifting when observed.
In spite of all this, we still don't know -- and can't tell experimentally -- whether light has the same velocity in opposite directions. Because *every* measurement of the speed of light somehow involves a round-trip for the light, it's just an assumption we make that the two legs of the journey take the same amount of time. It's possible that light travels at just above one half light speed on the way out, and then returns much, much faster at a much, much higher speed.
No matter how fast light travels, it could only possibly be measurable at the speed of causality "c" because of the limitations of matter to not be able to surpass reaction to light any faster than "c" - this means that any measurement of light at any point of matter = "c" or less, with each measurement at varietal points of "c" in comparitivity to each other. Meaning if lightspeed were instant, causality could never measure or react to it it beyond "c" anyway.
I accept the time dilation assertion, but I have a problem with it. It is based on the premise that is is impossible to determine which frame of reference is in motion. Imagine three spheres out in deep space with no windows, but only an incredibly accurate clock. One of these spheres does nothing. Another is going to spin, resulting in a simulated gravity of 1G. The third sphere is going to accelerate at 1G. In a couple years, both the spinning sphere and the accelerating sphere come to a complete stop. Shortly thereafter, the sphere that had been spinning begins to spin once again at 1G and the sphere that had been accelerating turns around and heads back, accelerating at 1G. They eventually arrive at the same point in space and stop. Two spheres had no linear velocity (the one totally at rest and the one that had been spinning) while the one that had been accelerating reached relativistic speeds. They get out and compare their clocks. It seems to me that if relativity is true (which it has proven to be time and time again) from this single observation they could tell whose frame of reference was in motion and whose was not.
"The third sphere is going to accelerate at 1G." Where it get all the energy? Simple calculation using Newtonian physics tell that the sphere reach the speed of light less than a year. (Of course that will not and can not happen).
Einstein would have been the best to enjoy greenery with, all his stoned thoughts were actual insights into how the universe works, rather than me and my friends with gems like, “aren’t thumbs weird?”
Really enjoyed this video, but one correction. My understanding is that the concept of "relativistic mass" (mentioned shortly after 23:00), i.e. the idea that an object's mass increases as it approaches the speed of light, is really a misconception. It originated as a sort of simplified shorthand created for pedagogical reasons to explain relativistic effects on momentum. But for instance accelerating an object to extreme speeds will not increase the gravitational force it exerts on other objects. Here is a link to video from Fermilab on the origin of the idea of "relativistic mass". ruclips.net/video/LTJauaefTZM/видео.html
Relativistic mass is not in itself a misconception (it is an extremely important concept in physics and the fields that use it) but you are right that often the way it is used and taught gives a misconception. An analogy can be made using the movie Lord of the Rings where "forced perspective" is analogous to "relativistic mass”. Force perspective is used in the movie, so a wizard appears to have a larger change in size compared to a hobbit. The concept of force perspective is not a misconception, but having a misconception about it may make someone think that a wizard has a real change in size compared to a hobbit. Just as the invariant size of a wizard does not actually change, even if the perspective does, the invariant mass of a system does not change, even if the reference frame (at a different uniform speed) changes and therefore its relative mass also does.
If light speed is the speed limit of the universe then we are never getting much past our own solar system. The closest star is Proxima Centauri and it's about 4.3 light-years away. Even at light peed it would be a nine year round trip. Short of something out of Sci -fi TV we are stuck here.
The way I understand it is that ftl travel is less about actually going faster than light and more about shortening the distance needed to travel to reach your destination.
@@Theseus77This is why you need to either fold the universe and/or generate wormholes for interstellar travel. Rather than travel as fast as possible, you can use extreme gravity to compress time or bend space in such a way that something very far is actually much closer than it shoudl be.
Here's a weird thing about light. It changes in different media. So, when light hits a piece of glass it will slow down and refract. But, when it comes out of the glass, it will speed back up. Where does that energy come from?
12:00 Thomas Young did his experiment with light in 1802. The electron wasn't used in a double slit experiment until 1960's. The graphic shows an electron gun. None the less, a nifty video.
Cool cool. Now can you send the part about the michelson morley experiment, the 5 minutes leading to it, and the information on relativity to a flat earther. That would be great.
If photons - which behave as waves and particles - have an origin source then they go from zero to C, which implies a sudden change in velocity and thus the occurrence of acceleration. Also, when light is reflected or refracted the photons alter course and change velocity, again implying acceleration.
@@TheKrispyfort Photons don't have mass, they ALWAYs travel at c. When reflecting, they change direction but not speed, in 0 time: if you want you can say they have infinite acceleration, and thus reach c in 0 seconds: remember that F = ma, or a = F/m, and since m = 0, you can have "infinite" acceleration, but that can only change its direction of course.
Yes, e.g. radar bouncing of a moving airplane. If you insist the 4 acceleration is perpendicular to the plane’s 4 velocity, you will recover the 2 way Doppler shift.
@@aaronhoney2217 What I was doing was making a small joke. If you were born after 2005 you may struggle to remember what it is, but historically people found fun in it !!
@@EamonCoyle While all I can say to you is: “Why don't you make like a tree and get out of here”, “Butthead” and “Manure! I hate Manure!” Loved your joke, that’s why I replied with a joke !!!!!!!! What do both Biff and “Mad Dog” Tannen dislike. It is another name for bullshit :) But you are right as a science teacher I should not use language so badly. I apologize, what I should have said was “The Biff Hypothesis” not “The Biff Theory”. A Theory is a well-substantiated explanation of an aspect of the natural world. A hypothesis is a tentative conjecture. "Sometimes science is more art than science." - Rick Sanchez BTW: I’m a child of the 70s , Gen-Xer. First saw BTF on VHS, watch it so much over the years the tape got corrupted. Saw 2nd two in cinema.
@@aaronhoney2217 80s N.Ireland here sir and if it helps the teacher in you I have been trying to work out all evening whether or not there was such a thing as the "Biff theory". We are all more that capable of a misreading I suppose and as someone slightly older I am glad it found the right audience. My earlier reply was in expectation that you were yourself a younger person given they tend to find humour is a bit too real lol
Albert Einstein : That's it! That's the theory of relativity! Light travels to us from the hands of the clock, to tell us the time. But, if we were to travel away from the clock at the speed of light... Marie Curie : The hands of the clock would appear to have stopped! Albert Einstein : Time would stand still! This moment *would* last forever.
If the basis of understanding something relies on the observation and measurements of an observer then it’s limited to what can be observed and measured by that observer. The lifespan of a proton is instantaneous to the proton even though we observe it differently but that doesn’t make the protons experience wrong
How do you not mention that the speed of light has ONLY been measured round trip? The one-way speed of light has never been measured, and it may be impossible to do so.
we can only measure the 2-way speed of light. we have no way and no idea how to measure the 1-way speed of light. it could very well have a different speed in each direction and we would never know
I may be mishearing, but he gives the speed of GPS satellites as 40 million metres per second, which is crazy. GPS satellites orbit at around 14000km/h.
I don't know who is writing these now, maybe it's because of Thanksgiving break ... Simon almost always sounds really smart, you know, when his writer has actually done the research; for example, I am not sitting on the toilet.
The speed of light in a vacuum is the same for all frequencies/"colours" of light. But the relative Doppler Effect will make light have a shift in frequency/colour when moving at different uniform speeds in different reference frames. The sun would appear bluer the faster your speed is towards it and redder away, relative to someone at rest on the Earth.
So the speed of light is not constant. According to light the speed limit changes. It moves at difference speeds depending on density of matter. Light moves slower through water or gas. But time does not move slower in water or gas. Time is just the measurement of change. If matter is in water slowing light down does that mean that matter in water has less energy? It would make so much more sense to call light a radiation. As it reflects off of matter showing different colors. Uv rays, infrared, x rays, gamma rays. All radiations. So what is visible light? Is there some certain spectrum? Some animals see in other spectrum of light. Maybe it's how we look at light and light we don't look at. What spectrum of light is the fastest? Full spectrum is different with each star. Light don't leave black holes but gamma rays and x rays do. Are they faster than light or have less mass? Or just increase or decrease of lights energy, frequency, and vibration? And wouldn't that all differ because of density of matters. What if we saw light only as heat? Black holes make more sense as being a bubble of no matter. The way we think of light is weird.
The energy in atoms can only go the speed of light which means the atoms move slower relative to their local state as they accelerate. In other words if you got to the speed of light your atoms would break their bonds. And you would become a mass of protons neutrons electrons. What happens when you slow down who knows what it would look like. Probably gas.
@@DrDeuteron i don't accept relativity its author spent his life trying to fix it. And if your not moving relative to space than what's moving? I think you mean you cant measure it. Which isn't the same thing
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Technically light can't be measured in one direction. Every time we have measured light it's been going in two directions, going one way than coming back. Einstein wrote about this long ago, he mentioned that light wouldn't be the same speed going in one direction than coming back. Veritasium made a video on this very issue
Space, can travel faster than the speed of light..it's called inflation!
"Thus, despite just sitting there on the toilet watching this video" I've been called out 😂
🙋♂️too
How did he know?
It’s spooky how he caught so many of us, hey?!? 🤣😂
No shit.....pun intended
Wow you'll on the toilet for 25 or more minutes.
No wonder John cries.
This reminds me of the Quote by Sir Terry Pratchett:
"Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it."
He should have got a Nobel Prize for that observation! 😆
One of the best videos of TIFO I have seen, I can't wait for you to tackle other physics topics in the same funny yet accurate matter (I should know I am a physicist). Very well written and delivered as always!
Sailor... not a physicist. Lol... Simon is awesome.
The GPS satellites travel at 14 million meter/HOUR, not per second. It would be quite a feat if we managed to get satellites to a speed of about 5% the speed of light ;)
\(^_^)/
U seem to know your stuff... If as he says at about 19:38 ish, that we would APPEAR to slow down, at near the speed of light, I always assumed that we would not notice it. Like in the twin paradox, neither would FEEL like their day to day life had sped up or slowed down? One would not feel like he was moving in ffw?
@@noahway13 That’s the general idea. This is even observed in certain unstable particles, as they’re able to travel much further than their half-life would suggest, because they’re experiencing slowed time.
It might seem that it has taken a very long time to figure this out, but on the grand scheme of things, we figured it out pretty damn fast!
DJ Cummerbund with yet another banger! I've watched a few of these types of mashes from several other artists on here and I gotta say this guy has the most spot on mixes of all. Beats all smoothly locked together, all pitches perfectly matched, seamless vocal transitions, each mix sounding like it was written as one song start to finish, well done good sir, well done!
Huh. I didn't think I'd get a refresh on physics from Simon today. Someone definitely did their homework.
Some easy listening at 6:31am haha.
You’re awesome Simon!
It's only 4.49am
Are you a time traveller from hours into the future?
@@mikeharris5681 i’m in Australia. So from your perspective, yes I am!
@@MLG85 that explains it, your clock is upside down
The way I heard that story before was that James Clarke Maxwell calculated the speed of propagation of electromagnetic wave and because it was pretty much spot on the experimental measurements of value of light he surmised that visible light is indeed a form of EM radiation.
Simon, did you do ADR in the bathroom?
I'm thinking Einstein must have been pleased to find out about the Lorentz-Fitzgerald transformation since it would have followed from his thought experiment. I also didn't realize that Galilean relativity played such a vital role for him (and is still valid).
Hi Simon, this is one of my favorites. Compliments to the writer on this episode.
as i sit here on the toilet besides the massive amount of energy I contain, there is something else that is about to be released and uncontained. Thanks for the vid Simon, always a good watch.
Well done Gilles, great script, well done all of you, good work, i really enjoyed video
Light speed knowledge being illuminating....I can't say it was the best knowledge given in the video, but it made the entire video worth it!
Light (or any electromagnetic radiation) is weird stuff. If you wiggle the electric field of nothingness, that wiggles the magnetic field of nothingness, which wiggles the electric field of nothingness, and thus the wiggle propagates forth through the nothingness. c depends on how fast those wiggles can wiggle each other.
Achtually 🤓that’s a common misconception. The relations between the fields are not causal. See: Jefimenko’s eqs.
But c does depend on how hard the couple. Not how fast.
@@DrDeuteron Fair enough. It's even weirder because it's one wave that's always both electric and magnetic.
Are these intellectual jokes?
I'm not going to pretend I understood half of that... but I still found it fascinating. Great doc.
What an amazing AHA! moment that must have been!!!! To realize that when Jupiter is farther away the light takes longer to get here
For a bit around seventeen mins in, with Simon's accent, I found myself singing Monty Python's Galaxy Song :P
I was indeed wondering, where and how did we originally devise or calculate the speed of Light; Perhaps more accurately called "the speed of Causality"
As a man of exquisite passion within radiology profession (CT Technologist), with a good knowledge of EM waves, XRay creation, photon behavior, etc, etc, etc, very good job.
24 minutes just so Simon can do a light pun
Thank you Simon this has truly brighten my day
One interesting side note, if Einstein is right then we can't know the speed of light with absolute certainty. The best we can do is measure the speed of a round-trip, light emitting from a source, striking a reflective object like a mirror, and returning to the point of origin. The reason why we couldn't measure the speed of light in one direction is to do so we'd need two perfectly synchronised clocks, one at the source and one at the destination, and that would require us to be able to communicate between the source and the destination instantaneously, which is impossible thanks to the speed of light being finite (in a round trip, I'll get back to that later). or it would require us to synchronise the clocks in one place, then move one of them, but because of time-dilation the instant we start moving one of the clocks, it will go out of synch with the other.
As previously stated, we can measure the round-trip of light with extremely high precision, but that doesn't guarantee that the speed of light is always the same in all directions. It could be, for example, that the speed of the light on the out-bound leg is 1/2 the accepted figure for the speed of light, and that on the return leg its speed is infinite. That would give a round trip that matches the accepted figure for the speed of light, but we would have no way of knowing for sure that the light was always travelling at that speed for its entire journey.
Intuitively, it would seem that the speed of light should be a universal constant in all directions, but it's been demonstrated that the laws of physics don't operate in an intuitive way more than once (for example, the weight of an object has nothing to do with how fast it will fall, though intuitively you'd think that heavy objects would fall faster than light ones). There is no observation you could make or no experiment you could conduct that would prove one way or the other whether the speed of light remains constant.
Fundamental flaws in physics:
- Time = "what the clock reads"
- Gravity = General Relativity explains what it is (but actually 100% doesn't)
- Due to aforementioned misunderstanding of time: wave-particle duality appears to be a 'principle'. Likely more an aberration/flawed measurement based around a flawed base unit (time).
15:50 Our boi Galileo flexin' on EVERYONE.
There was a song about the twin paradox written by an Astrophysicist called Brian. That's the song '39' by Dr. Brian May of Queen fame.
Love the format of your programs. The difficulty I have with the twin dilemma is that it assumes a zero reference. Assume two ships in deep space approaching each other at nearly the speed of light. Which one is moving, and which one is standing still? There must be a universal reference for this to work.
They are only moving relative to each other. There is no moving through space.
Hey, that was a good condensation of the matter. I'd never heard about Galileo's initial proposition of reference frames. Nice!
Note to the writer: It would be more useful to talk about time dilation in units of x microseconds per an explicit unit of time. I'm sure physicists have a unitary standard, like microseconds per second, but those of us who are not deeply immersed in the field will not necessarily be aware of this convention.
I just had an interesting thought. I don't know much about the actual science of black holes but the effects of approaching light speed are remarkably similar to those of a black hole. You have the spaghettification. You have dramatic increase of mass and time dilation. It almost sounds like when a star collapses into a singularity, all that energy is transferred into acceleration and the singularity reaching near or at light speed is ergo reaching near or at infinite mass, is what creates the black hole. Once again I only know so much about the actual science so it's all speculation, but cosmic coincidences only happen so often.
In the past, we had the duration of the "second" and tried to measure how much distance it travelled. Nowadays we have the "distance" of light travelled, and we chose a whole number. Now the duration of the "second" itself, is measured by how much "distance" light travels. EXACTLY (whole number) 299 792 458 Metres. Because the Earth does not orbit exactly on time, we chose distance as the better measure of things.
How he know I'm sitting on the toilet watching this video?!
I had a double take at 21:22. 14 million m/s...wouldn't that be something? Little bit above earth's escape velocity, yes?
What about the time dialation/slowing effect when observing light arriving at the suface of a gravity object, and/or observing light emitted from at gravity object into vacuum? How is the measured speed of light affected?
Illuminating? This presentation was lit.
We technically can't measure light one way, but can going one way than coming back, but light isn't the same speed going both directions.
Light might not travel the same speed in all directions (but probably does). ruclips.net/video/pTn6Ewhb27k/видео.html
Love it!
Space tells mass how to move and mass tell space how to shape, something like that.
Albert E. is my hero.
This was a really fantastic video
I'm so old, I remember doing something similar to Galileo's experiment at school, on the playing field.
I found it illuminating! Excellent!
I don't think the speed of light is actually a limit.
I also don't think the edge of the observable universe is actually the edge.
14,000,000 m/s seems a little fast for a satellite.
I thought as much too; there do seem to be a few typos/errors in the script; its 14,000 km/HOUR, or 14 million meters per hour, only 3600 times faster than said. In due fairness, he recited speeds in "per second" many, many times in a single speech so whether the script had the error or he just misspoke is a job for the editor to slap in an on-screen annotation "Woops I meant to say per hour here" (EDIT: I even wrote 'per second' instead, supporting my hypothesis! Oops)
Well done with this video lot of info well presented
I have always wondered, is the absolute speed for visible light or some other light, or do ALL types of light travel at the same speed?
All light. Any massless particles, really. They must be massless to travel at that speed. Otherwise it would require an infinite amount of energy. Also, field perturbations, such as gravitational waves. The only “thing” I can think of that’s faster is the expansion of the universe.
@@BDB78 Since the expansion of the universe is an observed effect, not an object, it doesn't violate causality for its value of apparent motion to be greater than the speed of light. We could probably come up with a lot of "things" that are faster than the speed of light. If I point my finger at a star, and we define that point in space as the distance from my finger in that direction, and then quickly move my finger somewhere else in the sky, that 'finger point' moved faster than the speed of light at that distance.
But the finger point isn't a physical object, and the expansion of the universe is just an observed effect from a huge universe full of tiny changing values.
Thanks for putting a lampshade on that exposed purple light bulb :)
Fascinating tangent Simon let’s carry on
4:23 Rene, in the Afterlife he didn't believe in : "OMFG ! I HATE that picture of me so much, I look stoned, and a lecher".
Honestly, you're channels are how I detox from the stupidity of the internet... I mean that sincerely. Always interesting.
So, we humans are batteries. Where have I seen that before 🤔 😅
We humans are made out of matter and all matter contains atomically bound energy. There's no way we have to tap that energy though. Only certain radioactive isotopes can make atomic energy. Which we humans do not possess. If you did you'd die quickly. It's a fairly popular assassination technique in certain circles to inject victims with radioactive isotopes. They usually use Polonium-210.
😂 red pill or blue pill
@@mightymicroworlds4566 I don't need blue pills (yet), so I guess I take the red one.
Interestingly, we are only "guessing" that the speed of light is c in all directions, due to it being the information speed limit of the universe its possible that it is 2c in one direction and instant in the opposite. All we know is that light makes a round trip at an avg speed of c
Actually, all we know is c-square is constant , its square root is an absolute value independent of direction. This is because "c" comes from the two-way wave equation ( a second-order linear partial differential equation) not a single one-way wave equation. Note "c" is a scalar value of the two-way wave equation so it does not make sense to ask what the direction of a scalar value is, its undefined. So the best or worst you could say is that its speed in a direction can be anything you want or nothing at all.
If we are looking back 13.5 Billion years with telescopes Today... then I wonder what has happened to all those Planets Suns and Galaxies that are all the way out over there since then. - #Universe
Time does not dilate and that’s been proven in quantum mechanics. Simon only explained the first half of the double slit experiment. The second half shows how the wave interference patter will go away depending on if the experiment was observed.
See time does not dilate because it’s constant across all space. We know this because atoms would literally tear them selfs apart if it wasn’t constant.
The speed of light (and all energy) changes when observed like with the double split experiment because it’s operating on a higher dimension than can be observed.
The reason so many people including scientists believe that time can dilate is the super accurate clocks use lasers to keep time. Thus the change in the behavior of light is uniform leading people to think time was the only variable that could change. When in reality it’s the speed of light that is shifting when observed.
Quantum mechanics is nonrelativistic
Try to explain how GPS work without the time dilation!
Thanks for the reminders! It’s been a while…
Laying in a bunk on my sailboat but please continue.
Thanks for all the hardwork fact boy🎉🎉🎉❤❤❤
Simon, your beard is looking lush mate
In spite of all this, we still don't know -- and can't tell experimentally -- whether light has the same velocity in opposite directions. Because *every* measurement of the speed of light somehow involves a round-trip for the light, it's just an assumption we make that the two legs of the journey take the same amount of time. It's possible that light travels at just above one half light speed on the way out, and then returns much, much faster at a much, much higher speed.
No matter how fast light travels, it could only possibly be measurable at the speed of causality "c" because of the limitations of matter to not be able to surpass reaction to light any faster than "c" - this means that any measurement of light at any point of matter = "c" or less, with each measurement at varietal points of "c" in comparitivity to each other. Meaning if lightspeed were instant, causality could never measure or react to it it beyond "c" anyway.
It is impossible to measure the one-way speed of light.
Both synchronized measuring devices must start at the same point and move away from each other at the same speed for the same distance.
Once your devices begin moving, they will no longer be "synchronized."@@machinemaker2248
Nah. There’s some synchronized clock experiment with sending and receiving points that can justify the speed of light passing by.🏎️🏇😊
Not so. What you suggest isn't physically possible.@@scottrok13
I accept the time dilation assertion, but I have a problem with it. It is based on the premise that is is impossible to determine which frame of reference is in motion. Imagine three spheres out in deep space with no windows, but only an incredibly accurate clock. One of these spheres does nothing. Another is going to spin, resulting in a simulated gravity of 1G. The third sphere is going to accelerate at 1G. In a couple years, both the spinning sphere and the accelerating sphere come to a complete stop. Shortly thereafter, the sphere that had been spinning begins to spin once again at 1G and the sphere that had been accelerating turns around and heads back, accelerating at 1G. They eventually arrive at the same point in space and stop.
Two spheres had no linear velocity (the one totally at rest and the one that had been spinning) while the one that had been accelerating reached relativistic speeds. They get out and compare their clocks. It seems to me that if relativity is true (which it has proven to be time and time again) from this single observation they could tell whose frame of reference was in motion and whose was not.
"The third sphere is going to accelerate at 1G."
Where it get all the energy?
Simple calculation using Newtonian physics tell that the sphere reach the speed of light less than a year. (Of course that will not and can not happen).
Most Enlightening indeed
I saw what you did there.
kicking butt and taking names simon
Einstein would have been the best to enjoy greenery with, all his stoned thoughts were actual insights into how the universe works, rather than me and my friends with gems like, “aren’t thumbs weird?”
Really enjoyed this video, but one correction. My understanding is that the concept of "relativistic mass" (mentioned shortly after 23:00), i.e. the idea that an object's mass increases as it approaches the speed of light, is really a misconception. It originated as a sort of simplified shorthand created for pedagogical reasons to explain relativistic effects on momentum. But for instance accelerating an object to extreme speeds will not increase the gravitational force it exerts on other objects.
Here is a link to video from Fermilab on the origin of the idea of "relativistic mass".
ruclips.net/video/LTJauaefTZM/видео.html
Relativistic mass is not in itself a misconception (it is an extremely important concept in physics and the fields that use it) but you are right that often the way it is used and taught gives a misconception. An analogy can be made using the movie Lord of the Rings where "forced perspective" is analogous to "relativistic mass”. Force perspective is used in the movie, so a wizard appears to have a larger change in size compared to a hobbit. The concept of force perspective is not a misconception, but having a misconception about it may make someone think that a wizard has a real change in size compared to a hobbit. Just as the invariant size of a wizard does not actually change, even if the perspective does, the invariant mass of a system does not change, even if the reference frame (at a different uniform speed) changes and therefore its relative mass also does.
It’s passé. It makes the famous eq work in all reference frames, but scalar rest mass is better.
I feel enlightened after watching this
😏
I appreciate the content of this video.
Thanks Simon for anothe awesome informative video but I can't say God bless you as you don't believe in one.
21:00 sorry did he say they travel at 14,000,000 metres per second!? Dammmn that's quick.
May I suggest a biographic about Ole Roemer. He has a couple cool stories.
I think my brain just melted 🫠
If light speed is the speed limit of the universe then we are never getting much past our own solar system. The closest star is Proxima Centauri and it's about 4.3 light-years away. Even at light peed it would be a nine year round trip. Short of something out of Sci -fi TV we are stuck here.
The way I understand it is that ftl travel is less about actually going faster than light and more about shortening the distance needed to travel to reach your destination.
@@Theseus77This is why you need to either fold the universe and/or generate wormholes for interstellar travel.
Rather than travel as fast as possible, you can use extreme gravity to compress time or bend space in such a way that something very far is actually much closer than it shoudl be.
Here's a weird thing about light. It changes in different media. So, when light hits a piece of glass it will slow down and refract. But, when it comes out of the glass, it will speed back up. Where does that energy come from?
See Poynting vector in linear media. The energy density goes up when the light slows down, but the power density remains constant.
12:00 Thomas Young did his experiment with light in 1802.
The electron wasn't used in a double slit experiment until 1960's. The graphic shows an electron gun.
None the less, a nifty video.
You are why RUclipsrs have mental health issues
agree with the energy spent on the seat
Depends what the light is going through i suppose. And what kind? A red light won't go through water very well. A blue light does.
This gets in to another feild of light and how wavelengths can be filtered.
Cool cool. Now can you send the part about the michelson morley experiment, the 5 minutes leading to it, and the information on relativity to a flat earther. That would be great.
You also forgot how they used Einstein's idea to create a formulae for happiness in the 90s; E+MC Hammer !!
Does light experience acceleration?
Is what we think of as the Speed of Light really the terminal velocity of electromagnetic radiation?
No, anything that is massless must always travel at the speed of light, there is no acceleration, it just has to have that speed.
No mass. The only interaction it can have in the universe is E.M.
If photons - which behave as waves and particles - have an origin source then they go from zero to C, which implies a sudden change in velocity and thus the occurrence of acceleration.
Also, when light is reflected or refracted the photons alter course and change velocity, again implying acceleration.
@@TheKrispyfort Photons don't have mass, they ALWAYs travel at c. When reflecting, they change direction but not speed, in 0 time: if you want you can say they have infinite acceleration, and thus reach c in 0 seconds: remember that F = ma, or a = F/m, and since m = 0, you can have "infinite" acceleration, but that can only change its direction of course.
Yes, e.g. radar bouncing of a moving airplane. If you insist the 4 acceleration is perpendicular to the plane’s 4 velocity, you will recover the 2 way Doppler shift.
FYI, it's James Clerk Maxwell, not Clark.
I do think you overlooked the later work by Doc and Marty McFly !!
What you're referring to is the "Biff Theory" . This has been shown to be a load of bullshit !!!
@@aaronhoney2217 What I was doing was making a small joke. If you were born after 2005 you may struggle to remember what it is, but historically people found fun in it !!
@@EamonCoyle While all I can say to you is:
“Why don't you make like a tree and get out of here”, “Butthead” and “Manure! I hate Manure!”
Loved your joke, that’s why I replied with a joke !!!!!!!!
What do both Biff and “Mad Dog” Tannen dislike. It is another name for bullshit :)
But you are right as a science teacher I should not use language so badly. I apologize, what I should have said was “The Biff Hypothesis” not “The Biff Theory”. A Theory is a well-substantiated explanation of an aspect of the natural world. A hypothesis is a tentative conjecture.
"Sometimes science is more art than science." - Rick Sanchez
BTW: I’m a child of the 70s , Gen-Xer. First saw BTF on VHS, watch it so much over the years the tape got corrupted. Saw 2nd two in cinema.
@@aaronhoney2217 80s N.Ireland here sir and if it helps the teacher in you I have been trying to work out all evening whether or not there was such a thing as the "Biff theory". We are all more that capable of a misreading I suppose and as someone slightly older I am glad it found the right audience. My earlier reply was in expectation that you were yourself a younger person given they tend to find humour is a bit too real lol
Nice one👍
Albert Einstein : That's it! That's the theory of relativity! Light travels to us from the hands of the clock, to tell us the time. But, if we were to travel away from the clock at the speed of light...
Marie Curie : The hands of the clock would appear to have stopped!
Albert Einstein : Time would stand still! This moment *would* last forever.
If the basis of understanding something relies on the observation and measurements of an observer then it’s limited to what can be observed and measured by that observer. The lifespan of a proton is instantaneous to the proton even though we observe it differently but that doesn’t make the protons experience wrong
That toilet comment felt like a personal attack lol
This is so enlightening
How do you not mention that the speed of light has ONLY been measured round trip? The one-way speed of light has never been measured, and it may be impossible to do so.
we can only measure the 2-way speed of light. we have no way and no idea how to measure the 1-way speed of light. it could very well have a different speed in each direction and we would never know
GPS uses the one-way speed of light. We've pretty much mapped the speed of light in every direction and every point within the earth's atmosphere.
I may be mishearing, but he gives the speed of GPS satellites as 40 million metres per second, which is crazy.
GPS satellites orbit at around 14000km/h.
Cheers for the emense volume difference between the advent and the rest of the video 🤷
This sitting there on the toilet watching this video….. I actually felt violated by that line
great video!
14 million meters per second for the GPS satellite orbit speed does not sound accurate.
It's not, that would be 14,000 km/s. It's probably closer to 140km/s .
14,000 kph, or 3.8 km/s.
Matter is a product of mortal mind. If you don't correspond with the illusion, you will escape the bondage of space/time.😊
Sorry, Simon. I'm not watching on my toilet. I'm standing in my kitchen, making a sandwich, *just like a woman!* 😂
I don't know who is writing these now, maybe it's because of Thanksgiving break ... Simon almost always sounds really smart, you know, when his writer has actually done the research; for example, I am not sitting on the toilet.
Great vid.
then is speed different in various coloured light?
The speed of light in a vacuum is the same for all frequencies/"colours" of light. But the relative Doppler Effect will make light have a shift in frequency/colour when moving at different uniform speeds in different reference frames. The sun would appear bluer the faster your speed is towards it and redder away, relative to someone at rest on the Earth.
So the speed of light is not constant. According to light the speed limit changes. It moves at difference speeds depending on density of matter. Light moves slower through water or gas. But time does not move slower in water or gas. Time is just the measurement of change. If matter is in water slowing light down does that mean that matter in water has less energy? It would make so much more sense to call light a radiation. As it reflects off of matter showing different colors. Uv rays, infrared, x rays, gamma rays. All radiations. So what is visible light? Is there some certain spectrum? Some animals see in other spectrum of light. Maybe it's how we look at light and light we don't look at. What spectrum of light is the fastest? Full spectrum is different with each star. Light don't leave black holes but gamma rays and x rays do. Are they faster than light or have less mass? Or just increase or decrease of lights energy, frequency, and vibration? And wouldn't that all differ because of density of matters. What if we saw light only as heat? Black holes make more sense as being a bubble of no matter. The way we think of light is weird.
Water and gas are made out of matter and matter has mass.
Mass slows down time.
The energy in atoms can only go the speed of light which means the atoms move slower relative to their local state as they accelerate. In other words if you got to the speed of light your atoms would break their bonds. And you would become a mass of protons neutrons electrons. What happens when you slow down who knows what it would look like. Probably gas.
Your post contradicts relativity. You can’t move relativity to space.
@@DrDeuteron i don't accept relativity its author spent his life trying to fix it. And if your not moving relative to space than what's moving? I think you mean you cant measure it. Which isn't the same thing
Good one