Why does time slow down near a black hole? (But, you don’t age slower) 

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Never stop making videos even if u get less views,some channels r really good and this is one of it

Fun fact: Watching this video on Miller's planet would cost you ~2.2 Earth years.

being on earth makes you age "slower" too. no matter how 'slow' it gets you will always experience a normal flow of time from your perspective. like the water planet in the movie interstellar. they experienced a normal flow of time from their perspective.

10:02 "That's what I am talking about!" I can't stop smiling. Your explanations are always to the point and easily understable, but these subtle comments, they are in the next level!!

This is by far one of the best Physiscs explantion channel that I have ever seen...

5:35 my brother, I love watching these type of videos, although I may not understand 90% of it. Let me just say it 5:30 mark, the way you broke down the apple falling towards the ground versus the ground, moving in the path of where the Apple was going just blew my mind. I never make comments on pages, but I’m taking time to tell you, bravo. I’ll be following your page for a long time!

How do you explain everything in one sitting? I haven't noticed any cuts, it's just you talking straight for 20 minutes without missing any points and with accurate emotions and energy. How is it even possible? You are a great teacher. Keep doing what you do. I cannot thank you enough. Your love for physics is unmatched. And ahhh I can finally watch Interstellar and actually understand a few things!

I think Einstein would be proud of you.

Love your vids that breakdown complicated topics into easily understandable chunks!

Every. Single. Video. I am BLOWN AWAY

This is the type of channel that should have 50 million subscribers. Don't stop what you're doing. You're one of the best at it. I've watched more videos on these subjects than I can count, but after watching only a few of yours, it all makes so much more sense. Not only that, I was able to easily connect other videos you made to related topics and they all come together in my mind seamlessly. It reminds me how my highschool chemistry teacher couldn't teach me something in a year that a college professor described in one sentence and I still remember it over twenty years later.

Listen to me, you sir are the best RU-vidr, period. Please never stop making videos

The concept of these physics are quite profound. Without time, motion becomes impossible. This also means that motion and speed are affected by gravity in crazy and unexpected ways. Simply being in strong gravitational field does indeed affect aging. So when we “measure” the age of our universe which is expanding, was a year really a year when the universe was more dense? It certainly seems that 1 year very soon after the Big Bang could have actually been thousands or even millions of years relative to a year that we perceive now due to the gravitational affect of so much matter being in a smaller volume of a more compact universe.

Amazing content as always!

Brilliant video - love the channel and your passion for physics!

This is amazing intuition into a very hard problem. Great job

Your visual representation is wrong. The two land surface should be outward and the force that pull in is centripetal

Thank you Mahesh, for showing me the connection between the cycloid (a rolling, rotating circle) and gravity in General Relativity I was looking for for 4 years. And it turns out to come from the master himself, Einstein! I love it ❤

I’ve heard other explanations about this stuff…but yours seems the best..thank you!!

he is a gem to the world we need to protect it!!!💖💖

Loved using your relativity series to expand my knowledge and then finally intuitively demonstrate the concept of gravity being a fictional force to my friends. I made the flat spacetime graph, made the cone graph, and a figure to show Einstein's clock in like 15 minutes in a late night discord call. Started with Galileo's transformations on a train to introduce relative velocities, then used a thought experiment about what happens when Galileo lets go of the ball from the leaning tower of Pisa in terms of Newtons first and second laws of motion first from Newton's classical perspective where the ball begins to accelerate due to an applied force, and Einstein's where the ball remains at rest. Using your graphs, I showed how the equivalency principle shows us Einstein's alternative explaination for our observations. It was incredibly fun for everyone and I thank you for your efforts. For the sake of time (pun intended) and my own limited intuition I asked them to accept time dilation and that we observe it now in many ways but I suppose ill be threading in an imaginary space station next time. Its still hard for me to take a leap in this demonstration from objects accelerating toward eachother with zero relative motion to the idea they could accelerate away from eachother without relative motion. Luckily, I live in an area with gravity so I'm confident it happens 😂

Best advice you provided us at the end of the video. I will definitely try it. And I love this video so much. Now I feel satisfied to know this concept 😊

I can't get enough of the intuitive explanations. The model is inverted in respect to the observer to simulate gravity so the direction of the simulated gravity is also inverted in respect to the observer. I almost got hung up on the difference between the planet or black whole from the ring model and which way the arrows point.

Thank you. You are an amazing teacher.

Mind blowing animation sir

Love how passionate and engaging you are! Your visuals and explanations helped me understand this at a deeper level so thanks🤙

Just discovered the channel and while I was watching the previous black hile video, a new one came out. What a coincidence?

I've stumbled across one gap in the explanation that bugs me. In the spaceship, what really caused the time dilation isn't acceleration as such, it's speed. So to understand why gravity “causes” time dilation, we have to show that massive bodies somehow make everything nearby “move” faster. You've hinted at a solution out by showing that motion is a way to combine acceleration with constant distances, but it would be great if there were a way to demonstrate it more directly.

I think comparing gravity (which is not a force) with a centripetal force (which is a force; the electromagnetic force to be exact) will only help as an intuition for what is actually happening and only muddles the water from there on out. The difference is that the centripetal force is actually accelerating the observers where as it's the space-time curvature itself that is responsible, which is definitely not an acceleration. Problem now is that we are back at the question from the beginning of this video. You should have sticked with your older explanation, which I'm glad you mentioned so that other people can learn it the proper way. 2 objects falling onto earth at different altitudes with the same initial speed will have different moving clocks although they don't accelerate; they are just moving in a straight line trough curved spacetime, meaning no acceleration and no change in their speed; and yet time dilation still happens.

These are so interesting and fun thank you!

This is the second video I've watched on this channel. Both times I feel absolutely certain that I now understand this stuff, right up to the point that the video ends. As soon as the video ends I go straight back to not understanding it at all.

Sir I have an very complicated doubt in 16:22 mins that is Einstein tells that it is due to Gravity the time slows down but also saying it is nothing but an illusion so last time again can you tell what is Gravity and why it slows time and the g arrow why is downward not upward??? Please ❤❤

bro i looooooooooveeeeeeeeeeeee your videos. they are soo awesome and on top of that they teach me sooo much. i hope you heart my comment😁

Okay the explanation is cristal clear and I love it. Question from previous video for the context to the current question. - But why time gets curved by mass in the first place? Why does Earth's mass equal more time at the ground? Edit 1: I've just watched this video and I will reformulate my question: Why do accelerated frames of reference (like the ones created by masses's accelerations towards each other) create time dilation in the first place? Edit 2: And why space also expands with mass?

*PLEASE ANSWER THIS QUESTION* If nothing can escape a blackhole so that means even information cant right?? If yes, then if there is a particle inside the event horizon of a black hole and the particle is entagled with another particle outside of a blackhole it wont able to interact or pass information to it EVEN IF WE DETECTED IT! SO DOES QUANTUM ENTANGLEMENT FAIL HERE or am i wrong?

Another Banger, but I am concerned that you're perpetuating a grave misconception: that time dilation between two locations depends on the difference in their local gravity field strengths...which is a natural conclusion from the rotating wheel "model" (it's not a model: it is real gravity, but an analysis gets into Ehrenfest's Paradox, which is hole nother video). Bear with me: Where in Earth does time run slowest? Dead Sea?, Challenger Deep? The Kola Super-Deep bore hole? No: THE CENTER! (iirc, it has accumulated a 2.5 year lag since "The Beginning"). OK: what is the local gravity at the center of the earth: ZERO, ofc, by symmetry, shell th'm, etc etc. Time dilation between two points depends on the difference in the gravitational potential energy between the two points, and is not related to the local field strength, which leads to a fun fact: with Newton's kinetic energy KE = 1/2 m v^2 and Newton's potential energy PE = GM/r time dilation is: gamma = 1/sqrt(1 - 2E/c^2). with KE (PE) for relative motion (gravitational potential). with the formulae diverging at v=c and the Schwarzschild radius, respectively. Don't trust me bro, Trust Albert!

Congratulations, you have just convinced people that the rotation of the Earth causes gravity.

A video on this topic was really needed... thankyou very much sir ❤

I would love a video about time dilation and quantum entanglement. Maybe that's just a special case of the relativity of simultaneity, which you've already covered. Anyway, I'd love to see one of your incredibly explanations on that topic! And just in case I do actually have your attention, I'll take the opportunity to say thanks for all the great videos. I agree with all the innumerable praises I've read in the comments section on all of your videos. Keep up the great work, whatever topics you choose to pursue!

Early comments give more likes...😊😊😊

This was a really nice video. Easy to understand, taking us through a series of logical steps. Good analogies.

Mahesh you're simply one of my favorite youtuber! found you just this year but totally in awe.

Well explained 👍

Thanks for the video! You're videos are so helpful on trying to understand the universe.

What would happen if the people near the center of the rotating space station started recording 2 videos - one streaming live, the other a stand-alone space smartphone that begins recording everything live at the center of the ship and keeps recording continuously whilst traveling to the outer ring (and has storage and power that will not run out). The streaming signal is broadcast while the space smartphone is continuously recording live the entire trip (and is put in a little escape pod and ejected toward the outer edge or traveling inside the ship on a little delivery Robot if it’s all connected and can reach the outer edge people). When the outer edge people start receiving the streaming signal, what do they see? Are there gaps in the broadcast signal, or does it show the center ship people in fast forward gradually slowing down, or what exactly would it look like to the outer ring people seeing it? Now for the space smartphone: When they receive the space smartphone they stop the recording (which has been recording without stopping the entire trip from the center people to when it reaches the outer edge people). They now begin playing back the recorded trip…does the video, now playing in their reference frame but recorded from its point of view in its reference frame from the center to the edge, what would that video look like to them? Would it start out playing super fast and gradually slow down or just be a super long, super boring video of endless hallways and passing by in “normal speed”? And just to be extra complicated, what if there were 2 devices recording, one digital and one on an old analog film recorder with rotating gears and wheels and endless videotape - how would the digital video compare to the analog recorded video with both now playing in this outer ring reference frame but recording all the time between? Does digital recording have any difference to the analog recording that had gears/wheels while recording? From the recording device’s perspectives time has just always been the same, but when the people in the outer ring frame of reference watch the recorded videos,starting the playback of both devices at the same time and watch them side by side…do they see video and hear sound that runs at different speeds from the beginning to the end? Do the 2 devices vary compared to each other? Or is just a boring standard speed video on both devices? How does the recorded video compare to the streaming video (if it had been recorded by the outer ring people while streaming and now also played back starting at the same time as the devices that travelled from the center to the outer ring? Hopefully this is an interesting thought experiment and not so obvious that I dont later think “why did I even ask that?” :-) And thank you, love this sort of thing; thumbs up and Sub’d! :-)

Please don’t stop making videos, You cure depression.

I love your videos, thanks for the explanations!!

I have a doubt... I don't know whether sir answered it or not anyways I can't find it or understand it(Also, my english isn't that good).... My question is that, space curvature is a visual way to represent objects slowing down due to gravitational time dialation right?..... If so then the curvature i.e, used as a way to visually represent the slowing down of objects, how does that bend the path of light .... According to sir's previous videos it is clear that due to time curvature and surface of a planet accelerating up path of light can be bend near a planet due to "time curvature" but what about space curvature.... How does it bend the path of light?.... That is my question sir😊.....

Just don't stop to keep building up the intuition videos And I'll ask to even make videos about some other physics topics like i am very in statistical mechanics and quantum mechanics Although I am enjoying the series 😊

Duse, you have such a fresh way of explaining things! I've watched hundreds of science videos, and so many of them repeat the same words as each other, but I'm always thrilled to find a fresh perspective~

Hey thanks for this awesome content. Can you make a video about Orbitals and related stuff. I really want to have an intuitive understanding about orbitals.

In previous video u said that nothing cannot enter black hole in external absorbers frame the according to an external absorber black hole dose not even exist first blace because nothing as entered the black hole is it sir?? please replay me thank u for the time

@Mahesh_Shenoy I have a doubt in your video of train paradox, consider a situation where there is another door/ sensor, before the mid point of tunnel. Then from the train's perspective, the order of doors closing/ sensors receiving messages will be right to left. Now if you look at the same scene with a stationary perspective, you will see that the new door/sensor closes first then the left and right door closes simultaneously. Now let us take the doors/sensors as events 1,2,3 from right to left respectively. Therefore, the order from the train's perspective is 1-> 2-> 3. But from the stationary perspective the order will be 2-> 1=3. So my doubt is that how could the order of events change. Also if there was another train moving opposite to the motion of this train it would see the order of events as 3-> 2-> 1 ( reversed ).

Great video as always!

omg!! the best explanation ever!!

Thank you so much for this. I just watched it with my 10 year old and she now has a much better grasp of gravity and time. I do now as well. ❤

The qualiry of your contect is way abouve channels even like vertasium. Thats what I feel. I had cofnisons on relativity for many years. Thanks to you that things are getting clear

Your channel is the best man. Thanks for the vid

Loving every video of yours... ❤❤❤

Thanks now I have a better understanding for what time is.

Thank you. Terrific video. I've been saying for some time that spacetime curvature is, in fact simply time dilation. When light travels through space it is always travelling in a straight line from its own point of view and what makes it lens and bend to an observer is in fact time dilation, to keep the velocity of light constant and dilate time to another frame it also passes you effectively curve the distance between them. It's an illusion, spacetime curvature is just a topography of time dilated frames of reference. But this revision of Einstein's explanation using relativistic acceleration explains it much better than I do. Time dilated frames of acceleration reference as topographical gravitation is the term I'll use from now on.

8:10 wow. That was the smoothest transition into sponsored content I’ve ever seen

Didn’t realize the Feynman technique was called that! Whenever I learn something or am doing homework, I try to pretend like I'm the teacher explaining the homework problem to students and it helps me learn a lot more. So yeah, that technique is applicable not just for youtube videos. Try it out if you're struggling in a class

Subscribed bro! Amazing channel 👏

you are the best teacher by far ! I love your videos ! I have another way to explain this but I am not sure if its correct or not. the big mass of the star (or blackhole) creates curvature in space time, which make the space around it more dense. for example 100 meters in empty space will dense into 20 meters around the star. so when I travel 20 meter near the star I actually traveled 100 meter at the same time. which means I moved faster by a factor of 5. thus creates the time dilatation due to faster speed.

So Mahesh, when spinning in your ring, the speed varies the farther out you are, but the speed is constant at the point of measurement yes? So you could argue an inertial frame of reference, unless you consider the angular momentum as an acceleration..

Sir please make a video on the formation of real and inverted images like how they formed on screen, what is screen, how they are inverted etc etc

I've still never fully got it. I understand that it slows time down, dang near to stopping it in a black hole, but I always can't help but think from an outside perspective. If I am watching a person near a black hole, and one way out in space, they should both age 24 hours on my clock if I watch them for 24 hours right? Just never understood how one covering more distance affected time. Time is only particles moving position, even objects setting dead still have subatomic and atomic particles, cells, etc. moving all over. So does heavy gravity just slow ALL particle movements?

I've had a question I'm hoping you'll address about approaching the speed of light or the event horizon of a black hole. The science communicator channels all seem to agree that when your ship exceeds the speed of light you disappear but they don't ever mention red shifting during the process. It seems to me that it wouldn't be an instantaneous switch from visible to gone, and that after the boundary is reached(supposing it were possible) you would red shift into invisibility as your ship accelerated further. From the point of view of the the ship going into the black hole it would look like the rest of the universe was moving on and aging more and more quickly, I think, and an outside observer would see time slow down and stop for the ship then it would appear to fade into infrared until it became undetectable. What are your thoughts? Edited for clarity*

One of the best explanations of special relativity

So Mahesh, is the conclusion that gravity doesn't really affect time dilatation, the speed difference due to different positions in the gravity well is the reason for time dilatation?

Ive got a question, if you take a 100 ton metal and a feather and you drop them the 100 ton metal will reach the ground first. If the ground execrates to meet the objects that are falling or whatever why would it be that the heavier item would reach the floor first if the ground would execrate towards the object?

In my opinion this explanation is an elusion as usual. It is true that both speed and gravity slows down time keeping but as it has never been explained how a big mass bends space time more than a small mass without having some kind of influence (force) from the mass I can't see why we might not as well use the old explanation. If you have an oscillating (like a pendulum) electro magnetic signal in any cell, atom or even the smallest particle then if it moves it will take longer for the signal to go from one side to the other and back for the oscillation. This will slow down time keeping. The faster the slower but it is not linear. It is there fore no big deal that if gravity influences light (as I believe has been found although I am still skeptical)) and light is an electro magnetic emission then time should be measured slower in a strong gravitational field. Mahesh is very smooth and fast in his explanations just like a magician. One must take it very slowly, stop often to think about it and then verify and I must admit it is difficult. Albert Einstein must have been the same as many of his explanations supposedly where not even his own.

you're a great teacher Mahesh!

Beautifully explained

I dont usually comment, but thats incredibly helpful!!!! Mahesh cheers from Brazil!

Best science explainer on RU-vid!

Awesome video enjoyed every bit of it :)

My village in Uganda is poor. We enjoy your videos. Thank you.

A very intuitive explanation. I wait for your videos. I have an opinion and need your input if I am somewhat wrong or all out wrong. Let's consider a graph of "speed" in a spacetime coordinate system with space in the x-axis and time in the y-axis. Does everything move at a constant speed c (speed of light) in a certain direction? If speed in space (x-axis) is close to 'c' then the time component (y-axis) will be much less. Vice-a-versa if speed in space (x-axis) is 0 then the time component (y-axis) will be maximum?

finally I understood the relation between "gravety" and time delation

Using the rotation analogy....the tengential speed is different...but the radial speed is the aame, correct? So, what is the analogue of radial speed in space-time?

Reall really great video and explanation. For us mortals who can't imagine 4d spacetime (pretty much everyone), this gives us a glimpse as to why time shows down in a gravitational well. Bravo Sir 👏 👏

The way I imagine it: the center of the circle is the black hole or point or intense gravity, and any circle you draw around the center is a timeline. So, to draw a complete circle, even though it may seem like line physical lines take the same amount of time to be drawn, the "length" of time (the circle) is longer.

Regarding the Model Discussed around 15:55, what would have happened if the gravitational force near the centre were more significant? In a case where there's a disc kept at a certain distance from a sphere horizontally, the centre of the disc is aligned with the centre of the sphere. In this case, even though an observer at the centre would see that the observer near the edge has a clock ticking at a slower rate, how can we possibly explain the slowing down of his clock due to gravity as compared to the slowing down of the clock of the observer near the edge, as the clock at the centre should tick slower than the clock near edge due to high gravitational field?

Brilliant videos. Quick question. If you take a 3rd person reference frame, how far away from the other reference frame is required to make it a different reference frame? e.g. Cooper goes into black hole so he has his own frame and he has proper time. Can observer (observing the extreme time dilation) be right next to him and watching from say 1m away? or need to be some minimum distance away to experience that time dilation? Thanks!

Watched this a second time as you explained this better than most creators do…so…I wanted to remember it💪

Excellent explanation!

it seems so small, but the relativistic effects on GPS satellites are actually HUGE! they would fail so fast without extremely precise programming based on their altitude

I am happy that sir is getting what he deserves ( views)

I wish I could explain this to someone as well as you do

I am really close to a brown hole within 3 feet and I am still getting older

I have only one question for you: Are you the voice behind those Kahn Academy videos about ciclotrons? Because those are also awesome and the way the narrator speaks, his maneirisms are very similar to yours.

i have many questions after studyiny general relativity- 1. Why do ground accelerate in the first place, if f = ma is correct some force should constantly act upon the ground to produce acceleration, what is this force?

Dude I love this guy.

We need more videos like this and less mindless nonsense on this platform. Good on you sir.

Very good video!!! One question if I may. The two astronauts on interstellar only felt the gravity from the planet because they and the planet were in free fall around the black-hole so the wouldn't (locally) feel the attraction of the black hole??? I'm having trouble connecting this with "feeling the gravity of the black-hole causes the clocks to slow down..." Any help appreciated!!!

He is not lying 😄 if you look at the accelerometer app on your phone while you hold it stil one direction is showing acceleration.

Mahesh Sir, I'm a big fan of yours. I have 2 physics questions. 1. A piece of ice is floating in a glass full of water. After the ice melts, will the height of the water increase or be equal? 2. Suppose I'm carrying a large stone in a small boat in a swimming pool. If I throw the stone in the pool, will the height increase or be the same as before? By the way, I learned the Archimedes law from your video in Khan Academy. Absolutely amazing!