Time Dilation - Einstein's Theory Of Relativity Explained! 

time dilatation can be observed when your wife says she needs 5 minutes to get dressed. On your watch it passed 45 minutes, but for her it's still 5 minutes.

Einstein discovered this theory in his mind without the internet. I have the internet at my hands, I've watched this video twice and am still struggling.

For those who don’t understand why moving really fast makes you slow down time: Light must remain constant, let’s imagine you’re practising for a race with a photon who travels at -300,000 kilometers a second. You’ve trained really hard and you think you might be able to get close to the photon after getting a new personal best of 299,999 kilometres per second. You and the photon line up for your big race, everyone’s watching! You run your hardest and reach 299,000 km/s, but wait, the photon should only be travelling 1,000km/s faster than you since that’s the difference in your speeds. But instead, the photon is still travelling 300,000 km/s away from you. How can this be? Does that mean the photon is travelling faster than the speed of light? I cant tell you why the speed of light must remain constant, just the way it is. But how does it seem to travel as fast as you at 299,000km/s plus an additional 300,000km/s, that’s faster than light speed, which is impossible! What actually happens is the time you experience is slowed down enough so that relative to the photon, you’re actually stationary and it’s just zooming past you as if nothing is happening at all. This is because light doesn’t experience time, from the perspective of a photon the universe has started and ended in an instant. If we were ever able to travel at the speed of light even for a nanosecond, then the extreme time dilation would zap us into the end of the universe, literally instantaneously. This is what annoys me so much about people wanting to travel faster than light, like yeah, great idea, you’ll certainly find out if there’s a God if you do.

I had struggled with this for years, despite being a physicist and engineer. The problem is that the thought experiments on this topic are fallible in many ways, if taken too literally. [For example, what if the clock tower was on a train moving away at the speed of light from a stationary observer, or if the observer was on a train that started on an approach to the clock tower, then continued past at the speed of light?] For me it took a completely different perspective to understand it, building it up in stages: 1) If every particle in the universe was static with respect to each other, there would be no interactions, and it would seem time had stood still, because nothing is changing. For time to become apparent, particles need to move and interact with each other, energy has to flow. 2) The speed of light is a universal constant. Do not consider light as an object, like a ball moving through space. It is a limit on how fast events in one region of space can cause events in other regions of space ("causality"). 3) If you were travelling at the speed of light, the atoms and particles that make up your body would not be able to move in the direction of travel (relative to the centre of your body), since they would have to travel faster than the speed of light (violating causality...the outermost molecules of your body would arrive at your destination slightly before you should be able to arrive!). Hence all the particles in your body would actually be static relative to each other, and therefore you wouldn't be ageing. Furthermore, you wouldn't be able to have a conscious appreciation that your ageing had ceased, since even "thinking" would require movement and interaction between the particles in your brain. 4) Since any object's perception of time is relative to the "relative interactions" of the matter it is made from, it cannot perceive the difference between a tick (at zero speed) or a tick (at near the speed of light....a "tick" is a "tick" according to the object observing or recording its own time. Due to the principles of a universal speed of light and causality, moving through space will necessarily slow the mechanism of the moving clock, and by an equal amount, the mechanism by which the moving observer is able to observe the clock. A clock moving through space actually does tick slower than a clock not moving through space. [A profound thought regarding point (2): If the speed of light is measured by causality, and causality infers change, and change infers the passing of time....if time didn't exist, would there be a speed of light? Would there be light?] In the context of this perspective I can go back to the original thought experiments and understand which aspects of them are useful in deriving the maths. These are all my own thoughts. I don't know if any professor of physics would validate them. But where the original thought experiments left me feeling dissatisfied, this new perspective helped me.

Time dilatation is when the alarm rings 7am, u wake up and blink your eyes for half second, and its already 730am

Anyone else not here from school and just interested in spacetime??? Edit: thank you guys so much for 5k!!

The fact that Einstein thought about this experiment and could accurately predict it’s result without even knowing what would happen is astounding If he was alive now,he could probably accurately predict what is inside a black hole and what would happen to human in it😢

My smooth brain hurts

Einstein travelled home by a tram That's all i understood

Cop: “Do you know how fast you’re going?” Einstein: “Speed is relative officer”

A long long time ago, I remember being told in the 5th grade of the 3 dimensions and then hearing my teacher say "some people even say there is a 4th dimension". On the way home I told my dad, "If the first dimension is height. Then length, then width....then the 4th dimension has to be when that object exsisted.". So I like to tell myself I theorized space-time as a child. (I mean, not really but close enough lol)

now i know why i am not smart at school way back then, even now i still dun understand after watching this video 😂

Einstein: Want to hear a joke? Me: Of course Einstein: Time Me: I don't get it Einstein: Exactly.

Let's just acknowledge how all of his theories were "imagined" before he proved them

Thanks, gradually after watching these extremely useful videos a few times, I am beginning to understand these concepts of time dilation and Einstein's theory of relativity.

The first equation for velocity in relative intertial frames were actually not discovered by Einstein but by Galileo. Loved the video very clear !

Teacher: why are you late Student: i'm not late, its time dillation

Imagine the things Einstein would've discovered if he was alive today

The animation is so good . Good work man 💓

you explained really nicely i had to watch many videos to understaand time dilation but this is the best one

I’m going to need this dumbed down even more

Me falling out of an airplane: AHHHHHHHHHHH! Einstein: Notice how his photon clock is creating a triangular shape due to the stretching the duration of a second.

It takes such an incredible imagination and fantastic ideas to derive this. To take such leaps and bounds in thought. I would love to have his brain for a day and just experience his perception, etc.

Amazing stuff; the moment I learnt the speed of light is not about light, but causality, I started to understand causality probably dictates all the experience of space and time we have; and it makes sense (causality is so fundamental; like something needs to actually happen before you see it happens, there’s no way around it); I would even think causality would REQUIRE the universe to exist and exist in the exact way we see; hope some great minds can resolve this

"Your head is slightly older than your feet" Me: Because my head came out first! Duh!

It has always blown my mind thinking that “time” isn’t an abstract concept, but an actual real physical thing that can be influenced by motion and gravity.

Interstellar made me watch this video

bro my brain legit can’t understand this yet

" Teachers who make physics boring are not teachers , they are criminals " - Sir Walter lewin

police: *you are speeding* me: *no, I'm at rest w.r.t myself*

this video is insane it answered lots of questions I ask myself.

If you're a sprinter or know about sprinting, this is pretty easy to understand. The faster you move, the shorter amount of time you use. Also, the reason the earth doesn't roll toward or away from the sun isn't because of fabric being pulled. It's because the earth is rotating/spinning & not rolling. Using their example of a marble, if you spin a marble it it will stay where it is or move in a circle. If you roll it it'll roll. Since the earth is rotating/spinning, it can't roll at the same time. The sun bending frabric & forcing the earth to move in a circle or oval isn't necessary if the earth is rotating.

THEORY OF RELATIVITY VERY EASILY EXPLAINED Light Travels at a specific speed. When he watched the clock tower, the light that entered his eyes allowed him to watch the clock so if he travelled at the same speed of light, the light would never catch up to him so he would see the same position in the clock. Credits: Wiktor Kasz (This is a copied comment)

This channel is perfect. No music in the background, so I can perfectly listen without distractions. In the description is all authoritative academic sources.

This is so true and relatable. If you move faster through space, time slows down for you. If you move slowly, time goes faster. The proof is when I am late for work, time goes annoyingly faster for me.

An easier way to think of this is to consider the superhero The Flash. When he starts running, everybody around him appears to be moving in super slow motion to the point where bullets are almost frozen mid air. Were he to run at light speed, everybody and everything around him, down to the individual atoms, would slow down to a complete standstill. That’s all it is.

Can someone suggest another video that is even more simplified than this? Like really simplified. Kind of like a coloring book version.

Einstein ponders the truths of the universe in his free time. I think about what I'm having for lunch during mine.

Amazing! Finally a video that explains it so I understand! ⭐️

Each time I re-watch it, I learn something new

"7 years per hour here, let's make it count!' gets crushed by waves.

Is there a children’s version of this that I can watch 😂

I have seen this video quite a few times and I am beginning to understand these concepts. I am not fully there yet. Thank you for the video.

Who else finds this completely fascinating? I have never learned about time dilation in school. It makes it so interesting.

Maybe someday I'll be able to understand the whole of this video

-Narrator: meters... kilometers -Americans have left the chat

I finally understand why this is so revolutionary. Great explanation and animation. Depending on your frame of reference, reality is different. Reality is so much more multifaceted than I can have ever thought. What other new discoveries await us?

Thanks for explaining.I was also thinking about time dilation before I watched this video

Science is interesting.

Gotta love Physics. It’s fascinating once u understand it.

My feet: *celebrating their 18th birthday* My Head: Wait, You guys are 18?

I was a science teacher in Middle Schools. I'm glad that I half-way understood the theory of relativity before I watched this, because it didn't become any clearer from watching it.

Me: Watching this video My brain cells: Am I a joke to you?

Is it just me, or did it take 3 hours to watch this 8 minute Video ???

Einstein’s Relativity Theory briefly explained. In nature there’s no instantaneous interactions, therefore must have exist some velocity limit, which is the speed of light, which is invariant to the the different inertial frames of reference, that’s the key, hence the dilatation of time and contraction of space observed by those observers in those different inertial frames of reference one in relation to the other using the speed of light as a measurement’s instrument. Q. E. D.

7:20 Very nice animation! It shows nicely why the speed needs more time to bounce between the two borders despite moving at the same speed at for the other two observers - because it need a longer way. But I wish this animation would also explain why time runs also slower for the man on the hill and the man in the UFO from the perspective of the falling man. Because if we switch to the perspective of the falling / moving man, then from his perspective his own light bounce runs at a normal time, but if he looks at the man on the hill or the man in the UFO, then they also seem to movie slower (or their light bounce devices in this case). I always though that from the perspective of someone who is moving faster, everything from his point of view and "outside" of his sphere (like the two other people) would actually move faster and not slower too, since this would be the logical consequence. But apperently I'm wrong as I learned. I still try to understand why. It also kinda contradicts what is sometimes said by other sources or movies, like Interstellar. When they were on this water planet, from their point of view their own time ran at a normal speed but the rest of the universe (including Earth and humans) ran faster through time. But from the point of view of the rest of the universe, everything ran slower on the planet. Everybody says something contradicting. What's correct now? If I move in my spaceship close to the speed of light through the space and I watch outside the window of my spaceship to planet Earth, would I see everybody else moving like in a timelapse very fast or would they move slower like in a slowmotion from my point of view?

I don’t know why i keep watching these science videos, but i must admit they are fascinating!

"Infact your head is slightly older than your feet" * Me who lies in the bed all day *: 👀

a very nice video very helping for me

I've watched this many times yet still my mind can't wrap around the idea of slowing time.

Traffic police officer - you were over speeding . Me - but speed is relative.

Conclusion... Your head is slightly older than your feet.

Oh my god that thought experiment regarding Einstein and the clock literally blew my mind. It was like a light bult went off in my head. Wow.

Right when we thought we understood it near the end, you just had to throw that curveball in there “your head is slightly older than your feet”. . Great vid

everybody gangster till people start moving at the speed of light

my head is same age as my feet cos I'm always lying down

The thought experiment you mention in the beginning could also be explained like this - since he's moving at the speed of light, the light that repelled from the clock to his eyes is traveling at the same speed as he is

Informative! It was easy to understand. Very thank teacher!

The one part of this that will never click in my brain is the concept of aging differently based on what speed you are travelling, I've never seen that part of the law explained in a way that makes any logical sense at all.. I understand relativity, I understand that the faster you travel away from something (say, Earth for example) then the slower in time it appears to move, up until you travel at light speed where everything you observe back on earth shall appear to stop in time - I get that no problem. What I don't understand is that surely the moment you travel back towards earth at the speed of light, then wouldn't you just observe everything on earth moving much faster now, therefore technically "undoing" the slowed/stopped time that you previously observed..? How is time dilation anything more than a mere observation, how can it possibly be an absolute change in time if you end up travelling back to where you began your journey? I want to make sense of this and have tried for years but I've never seen or heard an explanation that does it justice.

Actually one big flaw about this video is the sentence "The faster you move through space the slower you move through time" and this really confuses most people here cause they get a wrong idea of the concept. Your own time still runs the same for yourself. Only if you compare your own watch to the clock tower you can see the difference and realize that time in your own referential passed slower than the time in the other referential, thus the word "Relativity" cause it's all relative to where you are and how fast you are. So the sentence is not really wrong but it visualizes a wrong idea.

This is quite a good video on this topic. So far I have understood that there is a contradiction in Newton's laws of motions that state that the speed of objects is relative and that the speed of light is an exception to this because the speed of light is constant regardless of where are observing it from. So Einstein came up with a solution to this. I will see this video again a few more times for me to finally understand this.

"Your head is slighlty older than your feet" left me dumbfounded

Imagine if someone distracted Einstein while pondering the theory of relativity

"The faster you move in space, the slower you move in time."

Big typo in the subtitles at 2:37, it's speed of light not speed of life. Thank you for correcting it :)

That last line is gonna mess with me for a while

Still doesn't explain why half an hour break is faster than half an hour work!

My mind was blown multiple times. I need to spend more of my free time contemplating the truths of the universe.

wow this was a great explanation thank you

imagine a world without this smart man.

Man, Einstein deserves the reputation as one of the smartest men to live with a theory like this

Usain bolt is the youngest man on earth😂

Wow, this is so mind blowing!

Forget discovering new things, my goal in life is to understand the physics already discovered

"Yes! Your head is slightly older than your feet" Argh, no wonder my feet takes me to the pub against the better judgment of my head!

youtube explained the Time dilation just by waiting 5 seconds to skip the advertisment but feels like 5mins

Thanks, this video gave me a different perspective of The effect of planet’s mass on aging process.

For those who didn’t understand shit The faster something moves, the slower time moves, because you’re moving fast enough that you don’t perceive time as everyone else perceives it

Guys I feel sorry to say that 😔 Time is just a concept , created by clock sellers to sell more clocks .

Thank you so much!!

the way i tested this, is by increasing the velocity of my clock. i threw it across the room, increasing its velocity, and sure enough, when i looked at it again, time had stopped entirely! crazy what science can do

Who is acting like he understands but he actually not😂

Simply I study while running. It gives me more time than my peers. Thats how I always stand first in my class. 😎

This should help people understand the concept better, i.e. 5 minutes at work is a lot longer than the 5 minutes immediately after pressing the snooze button . :)

I understood everything yet it still seems unbelievable

Nobody: Maxwell:enters with a magnet to represent electromagnetism

6:48 Both are watching a man fall from space and they both do nothing.

Hey how are doing these extraordinary animations! ...They are astounding man.Mindblowing .

Brilliant explanation