So in summary the speed of light didn’t change but the distance the photon travels did change due to taking longer to travel a longer distance. I think anyone can comprehend this. Yet, people aging a different rates because of this seems counterintuitive.
I'm having a frustrating time explaining this to a family member. They keep going back to an example of a mechanical clock so I try to explain frames of reference. Then I try to say "imagine that this planet and this ship are Im a different bubble of time" and now we are watching this video.
It is possible to derive 2 contradictory time dilation equations. Imagine that Sally is in a spaceship and moving to the right and is aiming a flashlight straight up and down so that Sally sees the light moving straight up and down and John is outside the spaceship and sees the light forming a triangle with the floor of the spaceship. Now imagine that Sally is aiming a flashlight upwards and towards the left while the spaceship moves to the right. Now the situation is exactly reversed. Sally sees the light forming a triangle with the floor and John sees the light bouncing straight up and down. Here's the details... Sally is in a moving spaceship. John is outside the spaceship. Sally is moving to the right at .6c. The height of her spaceship is .8 light-seconds. If Sally has a light clock with the light bouncing straight up and down the light will make a 3-4-5 right triangle from the viewpoint of John. If the change in time for Sally is delta T_o and the change in time for John is delta T then the following equation can be derived: delta T = delta T_o/((1-.6^2)^.5) Now Sally has a light clock but this time she is holding a flashlight at an angle of 53.13 degrees above the horizontal and pointed to the left. Now the leftward movement of the light exactly matches the rightward movement of the spaceship from John's viewpoint. Now the light is bouncing straight up and down from the viewpoint of John and the light is making a 3-4-5 right triangle from viewpoint of Sally. If the change in time for Sally is delta T_o and the change in time for John is delta T then the following equation can be derived: delta T_o = delta T/((1-.6^2)^.5) The 2 equations are in direct contradiction to each other. Special relativity is falsified.
LOL! Right? I understand that the ball travels a greater distance in case two, but I still don’t understand how time passes differently based on what speed you’re moving through space. Ughh…my head hurts.
A single 'time interval' last longer in a moving frame than the rest frame of reference. Time slows down for moving objects. So each clock tick last longer in the moving frame with respect to rest frame. So the time shown by the clock in the moving object will be less than the time of the clock in the rest frame.
@@psyphy I see. Also, when time slows down for these fast moving objects, is the object still going at the same speed, and does it look this way to a stationary observer, or would the object seem to slow down to that observer? I can't help thinking of 'time slowing down for an object' resulting in it moving past me at what seems a slower speed, but it sounds like this isn't the case, and maybe it is just the time within the object and inside it?
@@malteeaser101 Hey, I think I may have confused you. Here, measurements of time intervals are affected by relative motion between an observer and what is observed. Here, we consider one back and forth motion of the photon as an interval of time. So, the same interval seems to be more for the moving frame with respect to the rest frame. If you use this time interval as a unit to measure the time, the time in moving frame with respect to rest frame will be less as each single interval last longer. So what you said is true. If you compare the clock in both frames, the moving clock will appear to tick slow, thus causing less time than in the rest frame. I've edited my first reply to make more sense.
Yes. But, you see, here the 2 cases shown are exactly the same process but observed from different frames of reference. . The key point to note here is that the speed of light should be constant no matter what the frame of reference is. If we were using a ball that travels at a low speed instead of a photon, using classical mechanics we would just say that the velocity is different in both cases and time is absolute. But it is no longer possible in the case of a photon(light) because the speed of light should be constant in both cases. This forces us to conclude that time is not absolute.
It is happening to normal bodies here. It's not the photon that's effected. It's the moving frame of reference that is effected. Everything happening in this frame of reference will be effected by this time dilation to be consistent with the behavior of light/photon. The reflections of photons are used to measure the intervals of time here. So, the time slows down for the whole moving inertial frame.
Even if it would be bouncing ball instead of photon, with any constant speed then also the distance would appear greater to the outside observer then why do we emphasize on the speed of light here?
In case of photon, the relative speed won't be (c + speed of space ship) but in case of bouncing ball the relative speed will apear (speed of ball + speed of vehicle) & that's to make the real time constant for both the observer. In case of light, the time will slow down because speed of light is constant
To the outside observer it APPEARS that the photon is going a greater distance in Case 2. So it APPEARS time is passing more slowly there. This is similar to when you are moving away from a building. It APPEARS that the building is getting smaller. That's your perception from your increasing distance. You wouldn't say that the building is getting smaller because that's how you perceive it. Why would you say that time at the moving mirrors is slower because that's how you perceive it?
This is quite a valid question and I had the same doubt ( I still do kind of). The thing is, if these 2 Cases are just an ordinary ball bouncing between 2 walls (speed very less than speed of light), it doesn't appear as if time is passing slowly for Case 2. Instead it appears that the speed is increased for it. Velocities are relative for us. But the most important thing here is that, the thing bouncing here is not a normal ball (The ball also feels this. But its speed is very less than speed of light to actually make a significant difference). But a Photon should move with the same speed irrespective of our point of view. Not appear to be moving with that speed. (it's a postulate. For a proof you should go into Maxwell's equations and Electromagnetism). So time should run slow. It's quite hard to imagine, like quantum mechanics. It's weird. But that's just how it is. This slowing of time is actually tested using atomic clocks.
No. You are not dumb. It's just an unintuitive topic. This video was just an attempt to visualize a thought experiment from the book 'Modern Physics' by Arthur Beiser. It just gives a basic idea about the concept. To really understand it, you must spend some time reading some standard textbooks on the topic.
This is inspired by the book: "Concepts of Modern Physics" by Arthur Beiser. As it's a widely used book, I don't think this example is wrong. I have left out the derivations for the sake of simplicity.
Me as a dummy just confused as hell. It seems like the light is faster in the case 2 because it's completed at the same time as the case 1 with greater distance but, idk
@@user-pl7tf9gv8e You understand both cases are just the same thing viewed from different frame of reference right? Read the postulate at 0:23 . It's really important to understand this. No matter the frame of reference, speed of light should be the same. So time should change to make up for this. Sorry if it confused you
So in summary the speed of light didn’t change but the distance the photon travels did change due to taking longer to travel a longer distance. I think anyone can comprehend this. Yet, people aging a different rates because of this seems counterintuitive.
It would make more sense if they used Words instead of Music.
I'm having a frustrating time explaining this to a family member. They keep going back to an example of a mechanical clock so I try to explain frames of reference. Then I try to say "imagine that this planet and this ship are Im a different bubble of time" and now we are watching this video.
It is possible to derive 2 contradictory time dilation equations. Imagine that Sally is in a spaceship and moving to the right and is aiming a flashlight straight up and down so that Sally sees the light moving straight up and down and John is outside the spaceship and sees the light forming a triangle with the floor of the spaceship. Now imagine that Sally is aiming a flashlight upwards and towards the left while the spaceship moves to the right. Now the situation is exactly reversed. Sally sees the light forming a triangle with the floor and John sees the light bouncing straight up and down. Here's the details...
Sally is in a moving spaceship. John is outside the spaceship. Sally is moving to the right at .6c. The height of her spaceship is .8 light-seconds. If Sally has a light clock with the light bouncing straight up and down the light will make a 3-4-5 right triangle from the viewpoint of John. If the change in time for Sally is delta T_o and the change in time for John is delta T then the following equation can be derived:
delta T = delta T_o/((1-.6^2)^.5)
Now Sally has a light clock but this time she is holding a flashlight at an angle of 53.13 degrees above the horizontal and pointed to the left. Now the leftward movement of the light exactly matches the rightward movement of the spaceship from John's viewpoint. Now the light is bouncing straight up and down from the viewpoint of John and the light is making a 3-4-5 right triangle from viewpoint of Sally. If the change in time for Sally is delta T_o and the change in time for John is delta T then the following equation can be derived:
delta T_o = delta T/((1-.6^2)^.5)
The 2 equations are in direct contradiction to each other.
Special relativity is falsified.
This helped me literally zero percent 😂
But I got it😂 IQ level😎
LOL! Right? I understand that the ball travels a greater distance in case two, but I still don’t understand how time passes differently based on what speed you’re moving through space. Ughh…my head hurts.
Thank you for the explanation. It is very clear.
Isnt time in Case 2 longer because the photon covered a longer distance at a constant speed in both cases? am i getting it right?
Yes thats time dilation but explained not very well here
I thought time was lesser for the moving object? Or is this just the time from a particular frame of reference?
A single 'time interval' last longer in a moving frame than the rest frame of reference. Time slows down for moving objects. So each clock tick last longer in the moving frame with respect to rest frame. So the time shown by the clock in the moving object will be less than the time of the clock in the rest frame.
@@psyphy
I see.
Also, when time slows down for these fast moving objects, is the object still going at the same speed, and does it look this way to a stationary observer, or would the object seem to slow down to that observer? I can't help thinking of 'time slowing down for an object' resulting in it moving past me at what seems a slower speed, but it sounds like this isn't the case, and maybe it is just the time within the object and inside it?
@@malteeaser101 Hey, I think I may have confused you. Here, measurements of time intervals are affected by relative motion between an observer
and what is observed. Here, we consider one back and forth motion of the photon as an interval of time. So, the same interval seems to be more for the moving frame with respect to the rest frame. If you use this time interval as a unit to measure the time, the time in moving frame with respect to rest frame will be less as each single interval last longer. So what you said is true. If you compare the clock in both frames, the moving clock will appear to tick slow, thus causing less time than in the rest frame.
I've edited my first reply to make more sense.
Is this just saying when sometime is moving over a long distance it takes longer than something over a short distance
Yes. But, you see, here the 2 cases shown are exactly the same process but observed from different frames of reference. . The key point to note here is that the speed of light should be constant no matter what the frame of reference is. If we were using a ball that travels at a low speed instead of a photon, using classical mechanics we would just say that the velocity is different in both cases and time is absolute. But it is no longer possible in the case of a photon(light) because the speed of light should be constant in both cases. This forces us to conclude that time is not absolute.
Simple and clear.
then why it happens for normal bodies they don't have constant speed right?
It is happening to normal bodies here. It's not the photon that's effected. It's the moving frame of reference that is effected. Everything happening in this frame of reference will be effected by this time dilation to be consistent with the behavior of light/photon. The reflections of photons are used to measure the intervals of time here. So, the time slows down for the whole moving inertial frame.
best explanation for dummies like me
I'm glad it helped.
Even if it would be bouncing ball instead of photon, with any constant speed then also the distance would appear greater to the outside observer then why do we emphasize on the speed of light here?
In case of photon, the relative speed won't be (c + speed of space ship) but in case of bouncing ball the relative speed will apear (speed of ball + speed of vehicle) & that's to make the real time constant for both the observer. In case of light, the time will slow down because speed of light is constant
So far the best one to explain the concept
Thanks man!
Really? I did not understand a damn thing there.
To the outside observer it APPEARS that the photon is going a greater distance in Case 2. So it APPEARS time is passing more slowly there. This is similar to when you are moving away from a building. It APPEARS that the building is getting smaller. That's your perception from your increasing distance. You wouldn't say that the building is getting smaller because that's how you perceive it. Why would you say that time at the moving mirrors is slower because that's how you perceive it?
This is quite a valid question and I had the same doubt ( I still do kind of). The thing is, if these 2 Cases are just an ordinary ball bouncing between 2 walls (speed very less than speed of light), it doesn't appear as if time is passing slowly for Case 2. Instead it appears that the speed is increased for it. Velocities are relative for us.
But the most important thing here is that, the thing bouncing here is not a normal ball (The ball also feels this. But its speed is very less than speed of light to actually make a significant difference). But a Photon should move with the same speed irrespective of our point of view. Not appear to be moving with that speed. (it's a postulate. For a proof you should go into Maxwell's equations and Electromagnetism). So time should run slow.
It's quite hard to imagine, like quantum mechanics. It's weird. But that's just how it is. This slowing of time is actually tested using atomic clocks.
How does it appear that the photon is covering a greater distance in case 2? Isnt it a fact?
Ok...obviously I'm really dumb cuz this still made no sense to me at all.
No. You are not dumb. It's just an unintuitive topic. This video was just an attempt to visualize a thought experiment from the book 'Modern Physics' by Arthur Beiser. It just gives a basic idea about the concept. To really understand it, you must spend some time reading some standard textbooks on the topic.
Ye I get how I can be near a black hole and when I get back my 1 year old is now 100 and I'm still in my 30s....😧
What?
yes yes, now i understand the concept. one must thank you for the other
More on time dilation: th-cam.com/video/4bOD4Y8ySGo/w-d-xo.html
Wow. This is really bad
💗💗💗💗💗
Nice.
Thanks!
That did not help me out at ALL.
this is so wrong.................
This is inspired by the book: "Concepts of Modern Physics" by Arthur Beiser. As it's a widely used book, I don't think this example is wrong. I have left out the derivations for the sake of simplicity.
Me as a dummy just confused as hell. It seems like the light is faster in the case 2 because it's completed at the same time as the case 1 with greater distance but, idk
@@user-pl7tf9gv8e You understand both cases are just the same thing viewed from different frame of reference right? Read the postulate at 0:23 . It's really important to understand this. No matter the frame of reference, speed of light should be the same. So time should change to make up for this. Sorry if it confused you
@@psyphy lol no no it's just me being dummy. Your explanation is the easiest for me though.
@@psyphy now I have to research why the speed of light is constant. Thanks for advance.
Bonjour
Bonjour!