SR2: The Light that will Lead the Way - Time Dilation
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- čas přidán 25. 03. 2014
- Part 2 of the Special Relativity series
CORRECTIONS:
[6:20] This ending segment is a lot more emotion-filled than it is scientific. Special Relativity is not the only way to explain the Michelson-Morley experiment. It's just that other explanations have fallen out of favour due to additional research. And who knows? Maybe SR will turn out to be wrong at some point, just like Newtonian gravity did after General Relativity started making more accurate predictions.
"Are You REALLY Standing Still?"
• SR0: Are You REALLY St...
"The Light that will Light the Spark - The Michelson-Morley Experiment"
• SR1: The Light that wi...
"The Light that will Win the Race - The Cosmic Speed Limit"
• SR3: The Light that wi...
Explore more relativity (Secondary School teachers, click here):
roberta.tevlin.ca/
Music in this video (downloaded from the CZcams Audio Library):
Morning Walk
Cancun
Dusty Road
CORRECTIONS:
[6:20] This ending segment is a lot more emotion-filled than scientific. Special Relativity is not the only way to explain the Michelson-Morley experiment. It's just that other explanations have fallen out of favour due to additional research. And who knows? Maybe SR will turn out to be wrong at some point, just like Newtonian gravity did after General Relativity started making more accurate predictions.
Proving SR to be false is a matter of time. Our science is built on the paradigm: "observation, expriment, theorem".
1. We observe our world: Just like Newton did (not with the apple but with planets), and just like Michelson-Morley did with the behaviour of light. This first part gives us ideas and we start building theories. The result of an observation is usualy an axiom. Something we start building on. Like "heavy objects falls to the ground faster than light objects (in non perfect scenarios)".
2. We experience: In order to prove these theories. We create, based on axioms we observed, something that can either prove or disprove what we think is true.
3. We acknoledge: The theory becomes a theorem once an experience proved it. This theorem becomes common knowledge and can and will be used in future proofs.
This logic have many flaws:
1. We are not sure about what we "observe". Our senses are not the best and we cannot rely on them (even when using telescope, your eyes can fail you). Our hearing is not the same. Looking into a 2D cut of a human body shows a very weird red curves. Looking into the true picture in our 3D world shows a total different thing. Why are we so sure that we look just like we do. Maybe we're funnier in higher dimensions.
2. Experiments rely on sensons which were made using theories proved by same experiments. Scientists knows better, but you never know when you miss something since the error comes from the part you are the most sure about.
3. Don't want to finish it on a stupid note, but moving earth is also questionable. We SHOULD investigate this idea. Everyone thinks relative time is consistent, but you can never know where a single mistakes can takes you.
4. ALL of our theories can be false. We are just not too precise to see that (just like what happend with Newton's gravity until mercury's orbit).
TLDR;
TLDR;
TLDR: YOU CAN'T HANDLE THE TRUTH!
Imo, Math is the biggest fraud in science, yet, the most precise tool we have. The one argument I have against Math is that it can never prove creation, if two sides of an equation are equal, with no modifications, this will never change. With this logic, which is not only an axiom but how math works, we can never prove how did the universe just popped out of nothing to existence.
calholli
1 second ago
Time is the constant... not the speed of light.
The light from the center of the bus does hit front and back of the bus at the same time. You are "saying' it doesn't appear so to the man outside, based on the Michelson-Morley Experimental predictions.. but that experiment failed... The light DOES hit the front and back of the bus at the same time, but to the outside man, it looks as if the front light is moving faster, and that is because> it IS moving faster. Doesn't it make more sense that when something is moving faster, it appears to move faster?
There is a difference between perspective and reality.
Though the light gets there at the same "time" it had to travel at different speeds to do it, this would cause the light to change the wavelength with the doppler effect, there for red shifting, displaying different color, ect.., but it would not appear to reflect at different "times".. time is the constant, its the speed that is variable. (this is what I believe, I know there is opposition)
Also you are comparing the perspectives of someone with a lack of information. No matter what the inside man measures and determines, it will never be in agreement with reality; he is lacking the information that the outside man knows (assuming inside man is unaware that the bus is moving). There is another dimension of complexity that the inside man has no way of knowing and therefor can never see what is "actually happening; his perspective is false to reality. To him, the light looks as if it is traveling at the same speed but it will measure as if he were the outside man if checked and measured exact wavelengths.
Another idea is that lets say that the light does contact the front and back of the bus at different times because it is moving. meaning that the light hits the rear of the bus first, and then takes longer to reach the front... Then the reflection "time" would also be the opposite, which would cause it to appear to hit at the same time when it does not.... meaning that the light may hit the rear first and reflects, but then has to cover more ground to reach the inside mans eye, and exactly reversed on the front................ again, the light takes longer to reach the front of the bus, but once it reflects, it much more quickly returns to the mans eye since he is moving towards it. so the reflection itself "DOES" happen at different times, but just looks different depending on which man you are. (inside or outside)
I am not sure that I accept SR. Like Tesla said it is like wandering off into equation after equation to build a structure that bears no resemblance to reality.
@@truthquest1194 yes but it predicts things which can be directly observed. Also it is an inevitability of math and science to slowly become more complex over time, therefore requiring more prerequisites and equations. It's like saying that "i am not sure i accept economics." because there are too many equations, and it bears no resemblance of reality. The complexity doesn't undermine it's validity.
Good job on the presentation. It has successfully removed the difficulties that many people would have in trying to understand this special relativity.
Thank you :)
You explained all of this so phenomenally… I was on the edge of my seat for the entire presentation. Thank you for helping me understand a little bit more about our crazy universe.
I'm kind of confused about who exactly am I and who exactly is my friend...
Hahahahhahahahahaahaha good point
I is friend. Friend is I. There is no difference because of relativity.
your friend is a contracted piece of shit who will always disagree with you on your measurements
Great job,very explicit,love the animations,and the explanations step by step.This should the physics lessons look like in the schools.
Thank you so much for making your videos! Your videos are amazingly simplistic making the complicated easy to understand. Love it!
Excellent as the part 1. Pls keep up the good work. Nice graphics too.
Thank you for your awesome videos! You're really helping me to study for finals :)
Good job!!
One of the best introduction and clear explanation, in a fun way.
Everybody tends to use the vertical light clock in their explanations, the easy clock explanation.
It would be nice to see 2 horizontal light clocks instead. We would see them with both being at rest, and then see them with one being in motion. We would then explain how it is that to the observers moving along with the mirrors, it seems to take the light the same amount of time to go from one mirror to the other mirror, no matter if the light is traveling in the forward direction, or in the reverse direction.
For instance, if the distance between the horizontal mirrors was 300,000 km, and then the mirrors were accelerated to a velocity of 260,000 km/s, an external observer would notice that the distance between the mirrors would have now contracted to a distance of 150,000 km. He would also see that the light takes about 3.73 seconds to go from the rear mirror to the front mirror, and he would also observe that it takes about 0.268 seconds to go from the front mirror to the rear mirror.
Yet to observers that move along with the mirrors, it would seem as though it takes the exact same amount of time for the light to go in either direction from mirror to mirror. An explanation of this would be nice to see.
With the mirrors at that speed - the light photon would never rich to the first mirror (bounc). The photon has no mass so it cannot be horizontally accelerated by the mirrors frame reference.
The effect would be the same of the clocks were horizontal. To see this you should consider the fact the moving clock would travel a certain distance.
+Nam Tran
So I can't reply directly to your question because Google+, so I'm replying here. Quote: "so in the end. t'=t.y or t'= (t-xv/c).y?"
Good question. t=y*t' is actually a special case of t' = y*(t - vx/c^2).
We derived the first equation using the light clock, which strictly travels to the right at speed v. So the light clock's position x = v*t.
Substituting this into the 2nd equation gives t' = y*(t - v(vt)/c^2). Expanding gamma and simplifying gives t=y*t'.
This shows that the equations are the same when x=v*t, but not necessarily otherwise.
The shorter equation is a special case for when we only consider one light clock by itself, and the longer one accounts for relative simultaneity, which wasn't covered too in depth in the video.
So in a nutshell, t' = y*(t - vx/c^2). The other equation only works in a specific case.
+Nam Tran We have to give credit to the Double Slit experiment, the Stern-Gerlach experiment, and probably others too. ;)
+Nam Tran In short, it can't. They are different equations and they mean different things. t'=y*(t-xv/c^2) can be deduced with more thought experiments involving length contraction, in addition to the light clock.
calholli
1 second ago
Time is the constant... not the speed of light.
The light from the center of the bus does hit front and back of the bus at the same time. You are "saying' it doesn't appear so to the man outside, based on the Michelson-Morley Experimental predictions.. but that experiment failed... The light DOES hit the front and back of the bus at the same time, but to the outside man, it looks as if the front light is moving faster, and that is because> it IS moving faster. Doesn't it make more sense that when something is moving faster, it appears to move faster?
There is a difference between perspective and reality.
Though the light gets there at the same "time" it had to travel at different speeds to do it, this would cause the light to change the wavelength with the doppler effect, there for red shifting, displaying different color, ect.., but it would not appear to reflect at different "times".. time is the constant, its the speed that is variable. (this is what I believe, I know there is opposition)
Also you are comparing the perspectives of someone with a lack of information. No matter what the inside man measures and determines, it will never be in agreement with reality; he is lacking the information that the outside man knows (assuming inside man is unaware that the bus is moving). There is another dimension of complexity that the inside man has no way of knowing and therefor can never see what is "actually happening; his perspective is false to reality. To him, the light looks as if it is traveling at the same speed but it will measure as if he were the outside man if checked and measured exact wavelengths.
Another idea is that lets say that the light does contact the front and back of the bus at different times because it is moving. meaning that the light hits the rear of the bus first, and then takes longer to reach the front... Then the reflection "time" would also be the opposite, which would cause it to appear to hit at the same time when it does not.... meaning that the light may hit the rear first and reflects, but then has to cover more ground to reach the inside mans eye, and exactly reversed on the front................ again, the light takes longer to reach the front of the bus, but once it reflects, it much more quickly returns to the mans eye since he is moving towards it. so the reflection itself "DOES" happen at different times, but just looks different depending on which man you are. (inside or outside)
Amazing video. You explained this very well sir. Have my like!
Great work! Please continue uploading more videos
Keep up the good work, these videos are very helpful, cheers!
Thank you very much! :) Part 3 is coming soon!
a great gem on youtube here
Great video man, keep producing!
I'm currently studying this part of physics at college, and I was banging my head against the wall because I just couldn't get it right.
You sir, made me understand special relativity.
+Bárbara Galasso Thanks! You made my day. :D
This presentation is great! Thanks! It really helps
Frame of Essence Thank you for this brilliant animation. I tried many times to understand Relativity and your work made it so simple and clear. Picture is worth 1,000 words.
- Am I right in understanding that this would happen even in a normal world, say with sound (but just much slower than light)?
- Effectively, all the events: 1) emotion of proton 2) photon reaching left side of the wagon, 3) photon reaching right side, 4) photons reaching the first observer etc. happen individually in their own time-frames. So depending where observer is, on the surface or on the train, he sees these evens as either separate or simultaneous.
Thank you kindly. :)
- Actually, all these weird effects only happen with light, not sound. The speed of light in a vacuum depends on the observer, so time dilation, length contraction, and other stuff ends up happening. The speed of sound only depends on its medium (air, walls, etc...) so it can be explained with non-relativistic physics. Although, it might be cool to think about what the world might be like with a cosmic speed limit of 300 m/s...
- Yep, you got it. Everything has its own sense of time, and will perceive events as simultaneous (or not) depending on its own velocity. Time is relative.
That was a really good way of explaining :) thanks a lot!
Awesine vid bud! thanks for the info!! have a good day bud!
Great channel.
WOW! I might not REALLY be standing still but this is REALLY amazing!
Extremely well made
1:45
As long as no acceleration occurs, not only does his clock tick slow according to your spacetime standards, but your clock ticks slow according to his spacetime standards.
Wow this is by far the best explanation and animation of special relativity I have seen so far, kudos to you!! I really look forward to seeing the next part, subscribed!! :) You definitely deserve a lot more views than this!
I myself am new to special relativity, so I have difficulties understanding the twin paradox, so please correct my if I'm wrong :)
So Person A and Person B are both on Earth. Person A decides to take a spaceship to a distant planet (of distance D away) while Person B decides to stay on Earth. Relative to each other, they both find that the times of the other person slows down. However, since the distance D is moving relative to person A, length contraction occurs and it takes a shorter time for person A to reach the distant planet relative to person A. On the other hand, the 'speed of D' was zero relative to person B so the length contraction never happened relative Person B, and thus it takes a longer time for person A to reach the distant planet relative to person B. Therefore, person B turns out to be older than person A when person B decides to come back. Is this a correct explanation?
Thanks for help in advance :)
Thank you very much! Also, Part 3 is actually already out: SR3: The Light that will Win the Race - The Cosmic Speed Limit
For the twins paradox, that sounds about right. Both Person A and Person B would each claim that the other is contracted and that the other's time is running slow. I would add in the fact that Person B actually "loses" time during the turn around at the distant planet. This goes beyond the scope of this video, since we are now dealing with accelerating frames of reference. (Person A's velocity changed from 'away from Earth' to 'toward Earth'.). I intend to discuss this in Part 4.
I hope this helps. :)
I think I'm going to really like your channel! :D
Really good vid bud, helped me out a lot !
Wow this is so well explained ! Thank you
great job guys..keep up the good work..
Can you put a separate video on length contraction. It's not at all clear from the sources available on net.
This should have more views. Really nice movie!
this is the best video that explains this. sue me if I'm wrong.
You Did a great job!! You should keep doing more lessons!
Thank you! Part 4 should be ready in a few weeks. :)
I've just newly subscribed - surprised I've not come across your vids before this. Feels like your vids should all have well over 10K views though but I reckon you're getting there- just a case of more people seeing them. BTW what program(s) do you use to do the animation?
Thanks for subscribing Lydia! I used Vectorian Giotto for animation in this video. It's free software, but it's really buggy and frustrating, so I've since switched to Adobe Flash.
@Frame of Essence, nicely done!! I think this video and the previous were a fantastic and simple explanation!! I have a doubt, hope you can shed some light (pun intended:))
At 4:30, if both the stationary (person on earth) and the person in the bus observe the other moving slower, how is that the "astronauts in space" or "people in rockets" age slower compared to those on earth? I mean, wouldn't one be slower to the other or have I missed something?
Thank you😃
Sir if there is inertial frame of reference then there is no time dilation ?
Was the time different compare to other clock after bus stopped? I mean at least slightest difference?
You are awesome too! Thanks for the upload, I enjoyed it.
U are simply Awesome !! Expecting to learn more !
Thank you! There will be more to come for sure!
hmmm in normal galilean relativity you could still get this effect because the light bouncing off the further wall will travel a length of time relative to the changing distance, making that light *appear* to have hit the wall at a different time when it actually was synchronized relative to the system containing the initial event (event = burst of light, container = moving bus)
pls make a video where twin paradox is clearly resolved...thanks :)
It seems that all things would make since to a single observer who could see all perspectives simultaneously. I wonder if it is required that all things make sense in the Universe? Is it possible for anything to exist that doesn't make sense in this Universe? Also, what if the Earth doesn't travel through the Aether but rather the Aether travels through all things in a wave that oscillates, sloshes, cavitates, within a defined boundary, as all waves do, like alternating current? I'm just trying to make sense of it from my perspective, point in space, but I can't possibly begin without a second point for me to relate to. It seems that nothing can be understood at all from a single point because a single point has no definition without anything to relate to.
can you find out answer of one question
if there is a planet X 1day = 1000 years on earth how far the planet is from earth ?
I also find this very interesting because I thought that gravity was the only thing that influenced relativity. Now I want to try experiments with it. Such as taking 2 identical stop watches and going out to an open highway traveling at high speeds. First stop watch in the car and second stop watch outside at a static location next to the road. Start both stop watches at the same time when the car reaches point A. Then stop both of them when the car reaches point B. Next we compare the differences between them and how much time passed inside the car relative to outside at a static location. Thank you for the video.
Would be cool but. Speeds are too low and stop watches are too imprecise. you likely won't get any noticeable effects.
the light detector of the interferometer Michelson is on the same frame of reference from which the light : in substance on earth and we move with it is obvious that we do not notice interference! Sagnac interferometer is correct because the light detector is external to the rotatable platform so we have two different reference systems
I understand this, but where does gravity come into the equation? Gravity causes time dilation, but why? I can't seem to find a decent explanation so any help would be appreciated! :)
Now where do i find the fixed solution ti the paradoxed at 4 56
To say that in one case light touches both ends togheter and in other case one first than second, that is like saying someone sees that a person was punched and the other witness sees the person wasn't punched and conclude that they are both right...
Vahagn melikyan Except one of them has a self-consistent solution and the other doesn't...
Frame of Essence I wonder if anyone has conducted michelson morley experiment in a moving bus... Assuming the ether wasn't moving (or planet earth wasn't moving relatively to ether) and the results showed that the light beams are in faze, than in a moving bus the experimental tools will move in ether henceforth the light beams should not be in faze. If they tried to run a test like that and results show that lights are not in faze, that means that earth isn't moving and the light c doesn't change it's speed relatively to everything.
Vahagn melikyan I would like to see this experiment done in motion relative to earth's surface too. Though the experiment is extremely sensitive in practice, so we probably couldn't get meaningful results from doing it on a moving bus. I'm waiting for the day someone manages to conduct it on the moon.
+Vahagn melikyan the most simple assumption to be made would be to conclude that there is no ether for anything to be moving through. there si certainly no real reason to postulate irrational theories to cover up the obvious deficiencies of general relativity and the measurements purely described without reference to the operating mechanisms made by quantum theory
Sure, message me on the facebook page, and I'll try to get to it when I can. facebook.com/frameofessence
I'm confused. The problem stems from using light to measure time. Another way of putting it (because the speed of light is constant) the clock on the ground and the moving craft are effectively different clocks ie. the clock on the ground has distance unit D and the clock on the craft has distance unit D" so obviously they tick at a different rate. It's the same as asking two people how long does a train journey take but one of the people has a fast-running watch (or slow-running watch). The time taken is the the distance divided by the speed of the train but the clocks are "different" so they show different answers. Question: what if you turn the light clock to the correct angle on the moving craft?
I enjoyed this presentation. If the light is traveling further on the bus because it is also traveling forward then light must have inertia or it would miss the target. I think there is a problem there and years of contemplating this has not resolved it.
So, if your friend is moving at say... 0.02 km/s (about 60 mph), would the speed he perceives light to be moving at be c+0.02 km/s relative to the ground then? sorry if this is obvious, it's late and i'm trying to wrap my head around it.
Nope, he will see the light moving at c because of the time dilation and distance stretching. Don't be afraid to watch the video again and again to understand, as said at the end, it's part of the physic that is counter-intuitive, but I promise you that you'll see the world in a totaly different way!
How to solve the time dilation paradox? I think, since time dilation is also affected by gravity, we must place the spaceship and the observer in the same gravitational frame. In this case, it will be the earth. In the earth frame, we can tell the observer is still and the space is traveling at a constant speed.
Great Great videos!! One question that nags me though.. If the guy in the bus moves close to the speed of light and his friend is standing still at the station. If the bus guy travels back to where his friend his who will be younger? The guy on the bus because he was travelling relative the the guy on the ground. Or the guy on the bus sees the guy on the ground as younger because the guy on the ground was travelling close to the speed of light relative to the guy on the bus. Or do they both appear younger to each other??
Thank you kindly.
This question used to bug me too. This video only deals with observers moving at a constant velocity. Since this question deals with changing the direction of travel of the bus, we're dealing with changing velocities, a.k.a. acceleration (which is beyond the scope of this video). It turns out that the one on the bus will be younger when they meet again, because he was the one that accelerated more. This is known as the Twins Paradox. I may do a video on this in the future.
so if 2 people A and B start in the same inertial frame of reference, and close together holding identical samples of radioactive material (or another reliable timekeeping system). A accelerates to an appreciable fraction of c, waits for some time, accelerates in the opposite direction until he is again stationary relative to B and then continues to accelerate to approach B at an appreciable fraction of c, before accelerating to again be stationary relative to B and close to B,
they now measure the relative strength of there radioactive samples (or another reliable timekeeping system) while standing in the same inertial frame of reference. what is the relative strength of the samples?
my simple analysis suggests this.
A observed Bs clock moving slowly on both the outward and return legs so B's radioactive source should last longer, B has the stronger source.
B observed As clock moving slowly on both the outward and return legs so A's radioactive source should last longer, A has the stronger source.
but now they are in the same inertial frame of reference with negligible relative velocity and distance, using the same Geiger counter how can they measure different results?
The issue here is that A is not in an inertial frame of reference do to their acceleration. A can confirm this by noticing a fictitious force in their frame during the acceleration. As a result, A's rules for time and space are more complicated than B's, and in the end A ends up losing time. So when they rejoin, A's material would be stronger than B's. Lookup the Twins Paradox for more details.
X= Vt, right? So the formulae x' = r ( x - Vt) becomes x' = 0 ?
Speed limits aren't confusing - its like running fast with a bungee cord tied from around your waist to a bag of bricks, and you can feel yourself slowing down when you reach the point at which the bungee begins to stretch - from there your maximum speed is dictated by what is slowing you down. This is exactly how light travels at millions of kilometres per second when it first explodes out of a light bulb filament, travels through the thick skin of the spacetime substance (aka ether - proven by gravitational wave detection in 2016 - don't worry, light used to be considered infinitely fast when they used lantern-on-the-horizon style experiments, so not being able to detect ether in a lab is shruggable) and then refracts back to the 300,000km/s speed limit that the substance (at this local density) restricts it to (and creates wave interference patterns etc). Of course, bungee cords are tied to less bricks in black holes where the density is lower and the speed limit is more like 5 million km/s. But light is unlikely to accelerate much if it started slow, because its not very heavy - and might only be a ripply wave thing that illuminates the ether and not a photon at all. Of course if the origin of a light sphere was located near a black hole where the substance is thin (low density), it may reach escape velocity to penetrate out of the universe and into the void, in effect expanding the universe as a little thorn in the side, or maybe passing out completely so it is no longer touching the universe (defined by our blob of spacetime substance like a blob of water in the zero g of a space station).
thank you so much
this relativity thing really blows my mind of
Good video congrats.
First, let me say that I really enjoyed your videos but I still have a question regarding the two clocks. From each clock's point of view, the other is going slower. BUT in real life, If one clock moves around the earth, then the moving clock will become a bit late. But from that clock, it was the earth that was moving and so the time should be delayed on the earth's clock. But it's not. Can you help me understand that part?
That's where things get slightly more complicated. In this case, the clock moving around the earth is not in an inertial frame of reference, because it is traveling in a circle, so its velocity is changing. It turns out that this clock will be the one that "actually" loses time because it accelerates more, similar to how things work in the twins paradox. I plan to make a video about this sometime.
Frame of Essence there are 2 famous fizeau experiment. i dont mean that one who's considered the first direct messurement of light(gear with slits), but that one to messure dragging of light in mediums. that is called fizeau experiment. interesting about this is the diferent direction(+-) of the dragging water. the results are far to little(they only show frenelian dragging coefficient) and all above: if the water stands still on one tube and goes with light direction in the other tube(0+), the result is 0. therefore the constance of lightspeed independent from the transmittor and receiver. this and the maxwell equatations on electrodinamics mainly drove einstein and lorentz(he took time to believe contant c though his lorentz transformation) to time dilation and length contraction. time dilation and therefore relativity theory as a whole, is perhaps the best sustained experimentally with the different lifespans of certain particles in particle accelerators together with the Ives-Stilwell-Experiment. also a experiment that i hardly understand and dont remember from 1960 might sustaine RT trough the electrodinamics. in short: mme restablished galilei. then 2 theories used to stand in confrontation: emission theorie(like newton said but in with waves and not lightparticles) against einstein relativity. fizeau partially and all above modern experiment seem to give einstein and the lorentz transformation the "medal".
In the twin paradox, a twin sent on a rocket which travels at a reasonable fraction of c. Well time slows compared to the twin at home.
But from the traveling twin's perspective, the other twin is moving quickly.
How can the clocks diverge only for one twin and not the other's perspective?
+lohphat The clocks actually do diverge in different directions for each twin when they are both traveling at constant velocity. The "loss" of time for the rocket twin actually has more to do with acceleration than time dilation. The twin that "loses" time will be the one that accelerated more. Since the twin who went to space and came back needed to change speed and direction at certain points, that twin lost time. I plan to make a video on this sometime in the future.
That diagonal observation of the frequency taking longer when the friend's light is moving away was not compared with the diagonal equivalent of the diagonal frequency of the bouncing light on approach. Pretty major omission from the test results. According to your maths, the diagonal aspect is what is creating the delay, not the moving away. Moving toward should result in acceleration. Surely the maths is nothing to be alarmed about. After all, my hand is much bigger than the coin sized sun in the sky. Maths gets in the way of explanations, and restricts inquiry. '?!' is a pretty alarmed reaction to something so basic, and its only because pattern-based mathematics is extremely flawed. I wrote a previous example of how limited maths is with this example: I can make many more sounds than you can spell. However, there are visual ways to gauge my sounds with a precise formula: A waveform. When maths evolves away from ape-like symbols and onto shape comparisons, then maths will stop having all of these ?! amazing paradoxes, which are not paradoxes at all in reality. My hand simply takes up more of the arc of my vision from this distance than the sun.
great explaination you give me enthutism about this subjrct eventhogh i got c
when the firts video ends i screamed 'mtfck you must finish this shit you cant leave me without explanation'
Hi. I really hope someone can answer my question.
If light is a particle (photon) it's very normal that one doesn't get any interference in Michelson and Morley experiment. If you simply apply classical galilean relativity by adding velocities of the Earth and the photons, the light path will be the same in any direction (perpendicular or parallel to the Earth's movement).
Michelson and Morley experiment maybe shows that there is no ether, but I don't see how it proofs that the speed of light is the same in any inertial frame of reference.
It really doesn't. It suggests it, but many other experiments have been done that better demonstrate the constancy of the speed of light.
Light is NOT a particle, particles are an illusion.
The Michelson-Morley experiment did NOT give a null result.
You are just like genius...
great video!!!!
If the person on earth ages more quickly than the person on the spaceship why is it that earth's rotation is slower than the speed of the spaceship travelling at almost light speed?
Make more please :D .... And try to improve the sound quality .... But after all .... That's great
Thank you for the feedback. More will come in good time. :)
The light operates at the same energy level regardless of motion or not, same with all bodies not just light
There is something I think I should point out about the Michelson Morley experiment. If it is used to try and see if the earth is or isn't spinning, When the lasers are shot in both directions one shooting against the supposed spin of the earth and one being shot with the spin of the earth. The information one should pay attention to is what beam of light arrived at the sensor it was shot at first or if they both arrived at there sensors at same time. The light beams bouncing back and onto another area is folly and I will tell you why. You see first if the earth is stationary then yes obviously they will arrive at final destination at same time but also if earth is spinning then even though the beam of light traveling to the right with the supposed spin of the earth has to travel further to get to target because it is in effect moving away from light, it then bounces back in the other direction at witch point the other end is moving towards it witch would be a shorter distance and it would be visa versa for the other beam of light going in other direction so they both would end up at the finish line at same time. My point is to pay attention to the first sensor the light is shot at and how long it took to arrive in comparison to the other beam of light going in opposite direction.
The path lengths are different because one of them follows diagonal paths and the other follows orthogonal paths (relative to the ether). It's similar to cutting a corner when crossing a roadway intersection. I encourage you to go through the math and find the paths lengths for yourself.
So am I correct in thinking that mass and speed have the same affect on time dilation? So the faster we travel the greater our inertial mass the slower time ticks, if this is the case then shouldn't clocks actually tick faster the further you move from a body of mass?
This is still confusing as hell but less so thanks to your vids :)
Sean Archer I'm glad to make this less confusing. Thanks :) Mass affecting time goes beyond the scope of this video, since it is part of General Relativity, not Special Relativity. But to put is simply, yes, being near a massive body slows time, similar to speed. If you place a clock in empty space and place an identical clock on earth, and stand far away from the experiment, the one on earth will run slower than the other.
Oh sorry, I should have expanded on my question. What I'm trying to understand is the reason why clocks on the ISS run slightly slower when they're further away from earths mass due to time dilation. I understand the basic concept of time dilation resulting from relative velocities, but for a clock to run slower when it is further away from the affect of earths mass wouldn't it mean that the ISS's inertial mass is larger than the earth? Sorry if my question still out of this vids scope.
Sean Archer
Well, time actually runs faster up in orbit, since general relativity's effect on time dilation is greater than that of special relativity. We want the clocks in orbit to sync up with clocks on the ground, but since time is running slightly too fast while in orbit, those clocks are set up to run slow to compensate. Minutephysics made a good summary of this: czcams.com/video/ky4RgRvVDoA/video.html
Frame of Essence Really?! Crap, there goes my basic understanding......
really cool video.
If there are two time bomb A and B. A is moving respect to B in space and B is stationery respect to earth .Both bomb are connected such that if any bomb blast first second will be deactive. Both blast time is fixed at 12 o'clock. Now according to B the clock of A is moving slow so B will blast first . Since B is in earth that means earth will be explode and A will be deactive. But according to A the clock of B is moving slow so A will blast and B will be deactive that means earth will be safe. Is it paradox?. Or that means both A and B has different realty in diffrent universe?
When first bomb will go off, the information about it is going to travel at light of speed. You can't connect to event to occur simultaneously without synchronize clock. And since one clock is moving relative to another they won't be in sync.
Great video!
Pity you don't dig a bit deeper, I'd love to see more math.
Here's another thought: What if c isn't the speed of light, but rather the speed of *causality*? In other words, if you cause something to happen on the moon, it'll happen immediately from the perspective of an observer on the moon, but you will not be able to see the results for 2.5 seconds.
Here's yet another thought: What we claim as being the speed of light is actually the average of the time it took to get from point A to point B and back. So what if one of the times was nearly instantaneous while the other was about 0.5 c? And any direction other than directly towards or directly away from the observer would be between 0.5 c and infinity, with the average always being 1 c.
Also, I like that part in the last video about light being a troll.
IF the light hit the mirror diagonally then does it actually reflect exactly perpendicular to the mirror? ????
Yes, the angle of incidence is equal to the angle of reflection.
Sunny, imagine a guy bouncing a basketball on the top of a truck as it drives past you and you have a very good video camera that can stop motion the bouncing ball....if you look at it frame by frame......even plot the ball.....it will appear to you as if the ball bounces at an angle.....just like the hypotenuse of the triangle in the light example.
OK, let's set up an event. Two people, A and B, have identical light clocks. The light goes up, hits the top mirror, and returns to the lower mirror. We will call that one round trip, one tick-tock, or one second. Secondly, we have a green light that will go on when 1 second is complete, and a red light that will go on when 2 seconds are completed. OK, so A ends up whipping by B at 260,000 km/s. In turn, B sees one second go by in A's frame of reference, hence A's green light goes on. That is the end of the event. Meanwhile, in B's frame of reference, 2 seconds had passed by, and so already his green light went on, then his red light went on, once 2 seconds had passed by. So the event is seen quite differently in B's frame of reference. OK, now let's see this event from A's point of view. In A's frame of reference, he notes that 1 second passed by, and thus his green light went on. But, to his confusion, not only did B's green light go on, but so did his red light. Based upon B's light clock, 2 seconds had passed by. So what happened to relativity ???
I just remembered the movie “interstellar” and how he travelled fast through the universe that his time dilated and his family started growing and see him still young. But hey, wasn’t he supposed to see them young while he ages as well? Instead, in the movie they showed him recieve their messages as older people while he stayed in his age when he left earth.
That happened because they were near a black hole. Time dilation due to gravity doesn't have that symmetry, so time near massive objects really does slow down.
So does the earth rotating at 1000 mph, revolving around the sun at 66000 mph, following the sun around the Galaxy, speeding through the universe, effect our reality of time? If we got out of the Galaxy and went motionless in space would we grow old and die in a matter of minutes?
66000mph isn't anywhere close enough to the speed of light to make a difference.
@@AMC2283 66000 is the speed of the earth traveling around the sun. You got to add the speed of the sun traveling around the galaxy and the speed of the galaxy traveling around the universe. Good luck with those numbers. And I don't think you have to travel at the speed of light before time is affected.
chas sisom it’s not fast enough to make much of a difference though
Starting at 1:37 you state the clock appears to be moving slower, supposedly due to the horizontal velocity of the moving platform. This, to me, seems contrary to the original construct that both clocks are the "worlds most perfect hypothetical clock" and, by inference, are perfectly synchronized to each other. Please, can you explain the reasoning why you state that the clock appears to go slower than the stationary observer, for the reason given below;The vertical distance that the light icon moves (or oscillates in) is static across both frames of reference. The overall distance the light icon travels on the moving platform travels a longer distance, because of the added horizontal component of speed in the x direction. Galilean mechanics at it's purest. Your video seems to presume that the time dilation component exists, before you engage in proving it.
Great vid. I watched it several times.
Thanks :) Here's the reasoning I went through when figuring this out. The premise was that light travels at speed c relative to the observer. (0:14) This isn't compatible with Galilean relativity, where the horizontal component would add to the light's speed, so this premise is dropped. So our starting premises are: (A) light travels at c for every observer and (B) an observer observes the same laws of physics when traveling at a constant speed relative to another observer. Now, we have two options: (1) the light beam travels on a longer path between ticks or (2) the clock is shortened so that time stays in sync. (It might also be some combination of the two.) I didn't mention the 2nd option in this in the video, and it turns out that option (2) has internal inconsistencies, so it can be disproven. Combining it with option (1) also leads to these inconsistencies. Therefore, we deduce that only option (1) results from the premises. The clock stays the same height, and the light beam takes more time to travel on the longer path.
Edits: wrong time stamp
Wicked awesome that you answered me! I am grateful that you took the time to provide this. I truly enjoy learning from people that are smarter than I.
I understand that this concept of the invariance of c is accepted almost universally, so I know my place at this moment. I merely desire to attain the same insight that is the current paradigm. However; your stated premise, "...was that light travels at speed c relative to the observer. (0:14)" leads me to deduce that the constancy of c was established prior to the Michelson Morely experiment. I'm pretty sure that one doesn't validate a premise of an experiment using the original premise.
I'm looking all over the Google-verse and have yet to find how this concept was derived prior to the aforementioned experiment, (I'm currently looking at the Kennedy Thorndike experiment but it is in the same vein as M&M). If you don't mind and have the time, can you point me to a few leads on the invariance of C prior to M&M?
My deepest appreciation.
It just clicked in my brainpan that J.C. Maxwell and his famous equations is where I need to continue my research. Please ignore my last request, and keep making these wonderful vids.
I'm glad you found what you were looking for :)
From the perspective of an omnipresent observer, all events are either simultaneous or not. Sequence is universal and absolute.
awesome video
Isn't the entire concept of special relativity contingent on the Copernican principle? In the Michelson-Morely experiment there are two options that explain the results. The first is what is presented in the first video and that is that the "ether" doesn't exist. The second option is that the ether does exist but that the experiment took place in a stationary location. Tesla actually called special relativity out for being a mathematical sleight of hand not supported by experimentation. If you assume a geocentric model of the universe, special relativity isn't needed to explain the M-M experiment. Also, the particle accelerator information isn't really conclusive.
"You and your friend should see each other as contacted" Why?
My thoughts exactly HighOnThunder. I would just simplify - how does the photon know that the bus is moving and how does it know in which direction the bus is moving? Save for that everything is just an OK ;)
You can't have both to be acurate, that a splash of light in the bus while the bus is moving the light hits both of the ends of the bus simultaneously, someone sees it different that it hits back earlier than front... Thats stupidity.
SR only seems weird if you do not fully understand it. If you fully understand it, then it is of no difficulty for you to create a simple geometric representation of it. From this geometrical representation, you can in mere minutes derive all of the SR mathematical equations, including the Lorentz transformation equations, and do so even if you have never seen the equations beforehand.
The light clock explanation is incomplete. A proper explanation is one that involves mechanical clocks, where it is explained why it is that the "OTHER" guys mechanical clock always seems to be the clock that is ticking slower.
how the lenght is contracted?
Length contraction is deduced from time dilation. This might help (see Derivation of Length Contraction): en.wikipedia.org/wiki/List_of_relativistic_equations#collapsibleTable1
ah hell, i still cant comprehend it, and i like to pride myself on my ability to understand obscure concepts...
3:12 that was so satisfying to watch
I thought if your perception is slower, then everything around you should look faster...
You're awesome.
What, in the place of a light clock, if I use a 'ball' clock? A rubber ball that can bounce back without any loss? In such a case, won't the ball clock with my friend who is moving relative to me tick slowly compared to mine?
Udhaya Kumar K It might tick slower or faster, since the speed of a rubber ball can be anything from zero up to (but not including) the speed of light in a vaccum. We can learn a lot from light clock thought experiment because the speed of light is always the same in special relativity. Though, if you and your friend were to strategically set up your own ball clocks to bounce at a certain speed, you would see the each other's ball clocks ticking slow.
Frame of Essence
Thanks. Another doubt... In the moving time clock, is the light are reflectors are set in an angle (not vertical) so that the light travels diagonally? Because irrespective of the case where the time clock is moving or not, the light, I think, would move always travel vertically not at an angle...
Udhaya Kumar K
No problem. :)
The mirrors are set at the same angle as before. Light still bounces off the mirrors in a diagonal path, because that's just what mirrors do: www.mheducation.ca/secondary/illustrations/books/Discovering_Science_8/full/Ch05//Fig05_10_178.jpg
Frame of Essence Thanks again friend. I am sort of more surprised now.The first time when the light pulse is triggered from the bottom reflector, does the source send it perpendicular to the reflector or it aims in a diagonal way?
The pulse is assumed to start at such an angle so that it always hits the centres of the mirrors. This is so the light never escapes so the clock can work properly. If the clock is moving from your perspective, that angle just happens to be diagonal. If the clock is at rest from your perspective, that angle just happens to be vertical.
6:19 It is the only way to explain how light can do what it did in the Michelson-Morley experiment
Special relativity is NOT the only way. That's just how scientist invented. You can never be sure if it's the only way to explain or there's other way
That's sort of true. Scientific theories are about building useful models. Special relativity has been an extraordinarily useful model since its inception. It's predictions comport with a great many observations that have been made since it was conceived to a very high degree of precision. It may not be a truly accurate description of how things work, but for now, it's definitely the most useful and effective one. It's similar to how Newtonian mechanics seemed to be correct until we learned where it wasn't. But, we still use some of its equations because they are accurate enough for most things people do on a regular basis.
The simplest explanation to the result of Michelson and Morley experiment, is that the earth is not moving. The relativity is just a fancy explanation to keep the earth traveling through space.
Awesome dude
you can run your clock at any speed, forward or backward and you can put it on film but you cannot live it
If neither observer knows anything about special relativity and they each pay attention only to the behavior of the two light clocks, then each will be tempted to infer (mistakenly) that the velocity of the light in the other's clock has changed. The trick seems to be to see exactly why they would be mistaken in drawing this conclusion. Question: The time dilation will be apparent in the difference between how the two clocks read after the experiment is over and the two are back in the same reference frame, right? If so, then shouldn't one friend's time have slowed down relative to that of her counterpart while her counterpart's time sped up relative to hers - instead of both observers' times slowing relative to each other?
Well, the entire derivation sits on the assumption that light travels at c in a vacuum in any inertial frame of reference, which was motivated by the Michelson-Morley experiment in part 1. If we assumed galilean relativity instead, we would deduce that light speed is not always the same, as you mentioned.
To answer your question, things get a little more complicated if we return both observers to the same reference frame to compare clocks. If the observer on the bus gets off and stands next the the observer at the bus stop, then the observer who was originally on the bus will have his/her time running behind the other. But if instead, the observer at the bus stop gets on the bus and stands next the observer who was already on the bus, then the observer who was originally at the bus stop will be the one running behind the other. It turns out that the observers will only “lose time” if they accelerate, i.e. change their velocity to perhaps line up with the other observer.
During the experiment while no one is accelerating, each observer will see the other’s time moving slow, but neither observer will actually be “losing time”. (It’s not supposed to make any sense.) It’s acceleration which leads to actual time travel to the future, not necessarily speed.
Frame of Essence If the bus's velocity relative to the bus stop is high enough for time dilation to become noticeable, will it actually be impossible for the two observers to compare their clocks without accelerating/decelerating?
Whether the answer is "yes" or "no," it seems instructive to take a closer look at how we are conceiving of the situation when we imagine the two trying to compare clocks across frames. In thinking about this, I found that I was implicitly asking, "At a given moment in time, how will each clock read? E.g., at the moment when observer A's clock reads 3:00 p.m., what will person B's clock read?" But these questions are misguided because there is no absolute simultaneity and no absolute standard of clock time across the two frames.
Can the experiment be arranged so that the two observers will definitely be able to see each other's clocks?
If it can be, then we can at least ask things like, "If observer A looks at her own clock when it ticks over to 3:00 p.m. and then immediately looks at the clock of observer B, how will observer B's clock read for her?" Suppose the answer is exactly 2:59 p.m. We might then ask, "If observer B looks at his clock when it ticks over to 2:59 p.m. and then immediately glances at the clock of observer A, how will observer A's clock read for him?" I gather the answer to the latter question will not be 3:00 p.m.
Progdil
That's absolutely right. The observers will never be able to see the same pair of readings when looking at both clocks, because simultaneity is relative. (Unless they're both in the same frame of reference of course.) As to exactly what each of them would see, there's a powerpoint from roberta.tevlin.ca which touches on this subject using a spacetime diagram, as it's a little hard to explain with just words. www.tevlin.ca/roberta/Rel/ST%20I/C%20Time%20slows.ppt
In order to be able read both clocks while maintaining their state of motion, what each observer could do is send out a message into space whenever their clock ticks. Each message would travel outward at speed c, and each would eventually be detected by the other observer. Knowing that the speed of each message is the same and that they are all coming from the same source, the second observer could record the message arrival times and deduce the rate of the first observer's clock.
Thanks! Could there be some way for the two observers to regularly exchange clock information so that the info arrives just as quickly for both of them-again, without either accelerating/decelerating? Suppose for the thought experiment's sake that wormholes can exist. Say there is a wormhole positioned nearby in the bus's direction of motion. The wormhole is such that when the bus goes through it, it ends up back at a position shortly before the stop. The bus maintains its velocity as it travels this same "circular" (yet rectilinear) route again and again, going through the wormhole and popping out at the same place relative to the stop, just a little before it. Now, say the two observers transmit their clock info to each other regularly in this cycle, at their respective optimal moments to minimize the travel time of their clock signals to each other. What will they find as they compare their clocks on each pass?
Progdil Well, now that we have a worm hole, I guess the observer on the bus would be the one losing time. This doesn't break symetry though, since the "wormhole" is moving relative to the bus, yet it is at rest relative to the bus stop. For the observer on the bus, I'd assume that they would see the clock at the bus stop moving slow, but after going through the worm hole (rather, after the worm hole passes around the bus since the bus isn't moving in this frame) the observer on the bus would see a new "bus stop clock" ahead of the bus with a different time setting than the clock seen before traveling through the portal. It would appear that the "bus stop clock" instantaneously changed positions from behind the bus to in front of it, and instantaneously wound its time reading forward.
Without the wormhole, the observers could still exchange and recieve clock information through some sort of encoding with the light pulses, maybe similar to how information is passed through fibre optic cables. If an observer wishes to use this information to confirm time dilation, they will need to know where in space their friend was when the message was initially sent. They might be able to do this by stratagizing ahead of time by setting their clocks to zero at the precise moment they pass each other, and promising not the change their state of motion for the duration of the experiment.
and that is AWESOME..!