# Time Dilation – Einstein’s Theory Of Relativity Explained!

One evening in the spring of 1905 Albert Einstein, then a patent clerk in Bern, after trudging through his day’s work decided to board a tram car on his way home Einstein would often wrap up his work as soon as possible to contemplate the truths of the universe in his free time It was one of these thought experiments he devised on that tram car that revolutionized modern physics forever While receding away from the Zytglogge clock tower Einstein imagined, what would happen if the tram car were receding at the speed of light He realized that if he were to travel at 186,000 miles per second the clocks hands would appear to completely freeze At the same time Einstein knew that back at the clock tower the hands would tick along at their normal pace For Einstein time had slowed down. This thought blew his mind. Einstein concluded that the faster you move through space the slower you move through time. How is this possible? Einstein’s work was heavily influenced by two of the most iconic physicists of all time First there were the laws of motion discovered by his idol Isaac Newton and second were the laws of electromagnetism laid down by James Clerk Maxwell Newton’s laws insisted that velocities are never absolute But always relative, so that their magnitudes must be appended by the phrase “with respect to” For instance a train travels at 40 km/h with respect to someone at rest However, it only travels 20 km/h with respect to a train traveling 20 km/h in the same direction Or it travels 60 km/h with respect to another train traveling in the opposite direction at 20 km/h This is also true for the velocities of Earth, the Sun and the entire Milky Way galaxy On the other hand Maxwell found that the speed of an electromagnetic wave such as light is fixed at an exorbitant 299,792,458 m/s regardless of who observes it however Maxwell’s notion seems incompatible with Newton’s notion of relative velocities If Newton’s laws are truly universal. Why should the speed of life be an exception? This presented Einstein with a daunting dilemma This conflict between the ideas of Newton and Maxwell can be demonstrated with another of Einstein’s brilliant thought experiments Einstein imagined himself on a train platform witnessing two lightning bolts strike on either side of him Now because Einstein stands precisely in the middle of the two strikes He receives the resulting beams of light from both sides at the same time However things get more complicated when someone on a passing train views this event while whizzing past Einstein at the speed of light If the speed of light conforms to the rules of relativity, then the person on the train wouldn’t witness the lightning strike simultaneously Logically the light closer to the man on the train would reach him first A measurement of the speed of light made by both men would differ in magnitude, this would contradict an apparently fundamental truth of the universe Einstein had to make a difficult choice. Either Newton’s laws were incomplete or the speed of light was not a universal constant Einstein realized that the two notions could coexist with a small tweak in Newton’s laws To get rid of the discrepancy in the measurements Einstein suggested the time itself for the man on the train Must slow down to compensate for the decrease in speed such that the magnitude remains a constant Einstein called this absurdity “Time Dilation” and his newfound theory “Special Relativity” Newton believed the time moved unflinchingly in a single direction forward Einstein however had just realized the time stretches and contracts varying with velocity Due to its malleability time like space Deserved its own dimension in fact Einstein claimed that the two were one and the same together they formed a four-dimensional fabric or continuum called space-time upon which the mundane events of the universe would unfold Einstein Suggested that massive objects like the Sun didn’t pull bodies like earth with a mysterious Inexplicable tug, but rather curved the fabric of space-time around them Forcing earth to fall down into this steep valley A highly simplified analogy is the dip in a trampoline made by a falling bowling ball If a marble were placed on that trampoline the marble would immediately roll towards the bowling ball in the center This is also true for Earth’s gravity We are pinned to the ground because space so distorted by the Earth’s mass pushes us down from above however the slump in the fabric around Earth is not uniform and Earth’s gravity grows more intense as we move towards its center where the curvature is at a maximum Therefore like the marble on the trampoline an object that falls towards the earth accelerates as it races towards the center of the planet It falls faster when just above the surface than it does say when it is slightly above the atmosphere But hey according to special relativity the faster you move through space the slower you move through time This means that time runs slower on Earth’s surface than it does above the atmosphere Now Because different planets have different masses and thus different gravitational strengths They also accelerate objects at different rates as we have learned this means a variable passage of time This is what happens in the movie interstellar when the protagonists land on a planet in the proximity of a black hole The gravity on the planet is so severe that one hour on the surface is equivalent to seven years on earth To understand how motion affects time let’s consider the simplest timekeeping mechanism A second passes each time the photon is reflected Let’s imagine two people one in a spaceship slightly above Earth’s atmosphere and the second on top of a small hill Just above the Earth’s surface Both are watching a man fall from space towards the ground Let’s say that the falling man is carrying the photon clock explained a moment ago What do each of the two men observe as the man falls past them? What they observe is eerily similar to what a stationary person would observe when watching a ball bounce in a moving train. As the man falls from space, the light in his clock would appear to move in triangles to the two observers This would mean that the light travels a longer distance consequently stretching the duration of a second It is obvious that the length of triangles the light traces and therefore the duration of a second is proportional to the velocity of the falling man When we recall that objects closer to the center of the planet fall faster We can determine the time would appear to pass slower to the man on the hill Than it does to the man in the spaceship above. Of course the difference is infinitesimal The difference between the time measured by clocks at the tops of mountains and at the surface of Earth is a matter of nanoseconds time dilation affects every clock whether it relies on basic electromagnetism or a complex combination of Electromagnetism and Newton’s laws of motion. In fact even biological processes are slowed down Yes, that’s right your head is slightly older than your feet

## 100 thoughts on “Time Dilation – Einstein’s Theory Of Relativity Explained!”

1. Science ABC says:

2. Dhruv bahl says:

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

3. Dhruv bahl says:

Newton didn't actually made laws of physics he stole that info from Galileo

4. Türt Gracilla says:

i feel bad for the man falling

5. Leon says:

That's a lot fo work creating this toon. Much appreciated!

6. Andree IP says:

I came here because of interstellar

7. ShonenSamurai says:

GunBuster has brought me here.

8. Michael Recore says:

Wth I don’t understand.. So, if you’re on that planet for 1hour, which happens to be 7 earth years, will you have aged like you would’ve those 7years on earth? Will I be sitting on that planet waiting 7 earth years for an hour to pass. Wtf

9. James clerk Maxwell says:

A cheating in the game physics not in reality.

10. Sameer Nagnoor says:

Say if Flash is running at the speed of light on the surface of earth, would time be slower for him?

11. Paola Varela Lerma says:

getting away at the speed of light from the tower, the clocks hands appear completly freezing., time has slow down. approching to the tower at the speed of light the clocks hands appear faster than normal.

12. Kunal Singh says:

I may sound very stupid maybe bcoz i can't really understand the time dilation but i feel like …..

if time and space are linked together than it doesn't matter how fast you move…the universal clock would still run the same for everyone. That means time will move same for everyone irrespective of your movement. Even if you're moving at the speed of light on earth …one day would still be 24hrs for you and for everyone else…i think you would just feel like the day is really long and that time is running slowly but in fact its actually unaffected for everyone.

13. sean lim says:

Einstein basically had what you call a 'eureka' moment, where he dreamed and dreamed and dreamed about stuff that nobody actually thought about. Many people thought they too could do the same thing and become rich and famous like einstein but little do they know that a 'eureka' moment doesn't usually happen once in a century or a 1000 years lol…

14. sean lim says:

Let's start an argument:

Time is the 4th dimension in our reality. Fight me, lol.

15. WARRIOR YT says:

It's funny how i thought I might be able to understand this

16. Emily Scannell says:

Velocity is relative, yes. Like if you were on a train, you would be moving 0 mph relative to you. But relative to the train you are moving (let’s say for example) 8 mph. It’s the same with time. The faster you go, the SLOWER time goes.

For example, if you were in outer space and moved at the speed of light, traveling two light-years away from earth and then two light-years back to earth. Only 4 years passed for you. But decades would’ve passes for everyone else on earth.
Time passes at differently for you and people of earth because everyone was moving at different velocities through space, you at the speed of light, and earth at approx 67,000 mph

That’s kinda it, of course this leads to more questions and more complicated theories, but once you can understand the basics then the other theories become easier to understand

17. Sean Choppin says:

Great video! The way in which these complex postulates (concerning space and time and their relationship to one another) are confined to more conventional and understandable ways of thinking is truly awesome. I’ve never had a better grasp of the theory of time dilation than I do now!

18. IBi SAUHARDA says:

19. Deepak Joshi says:

According to Hindu mythology, when 'Lord Krishna's died time stopped and which was beginning of 'The dark age'(Kaliyuga) in which we are living which will end perhaps by February, 6898.😊😊😊

20. Eggbert08 says:

Uhhh… Is Maxwell just happy to see me at 2:14??

21. The Reaper says:

Pls don't go hard on me because i am still young and stupid, but heres some questions i have about this video :

Why does it have to be that time stoped for einstein when he was traveling at the speed of light? It's just that light couldn't reach him yet so if he were to travel for days in the speed of light he wouldnt be able to visually observe the world but he would die of hunger right?

Speaking of light, the vid mentioned that the closer you are to an objects center of gravity the faster you'd fall. So how is light still at a fixed speed that can never change? Why wouldnt it travel faster as it gets closer?

22. Steve1 M says:

I really wanted to understand all of that

23. Saurav Rimal says:

marvel move towards bigger object in fabric because of gravity
can someone explain me??
fabric bend in first place because of gravity
so there is gravity because of another gravity??

24. Dark says:

But wouldn't the time only slow visually?

25. Antonio Mantovani says:

He was not so

26. Antonio Mantovani says:

Time doesn't exist, its useful sometimes, but is an illusion, created by us. Energy and Entropy that's the real time

27. gRiM says:

What exactly led him to postulate that the clock hand would appear to stand still while traveling at the speed of light? Doesn't seem like an intuitive conclusion 🤷‍♂️

28. Easin Arafat says:

brain.exe has stopped

29. ALSM says:

I don't think it was that hard to understand they exaggerate it. Just like the Mandela Effect, it was just simply false memory and they exaggerate it.

30. kwnstantinos slk says:

MIND BLOWN👏👏

31. Hernán Andrés Noguera Hevia says:

I’ve never understood the trampoline analogies to explain the curvature of space-time. They explain gravity by saying that the curvature in the space-time fabric cause bodies/objects to fall down the slope, but that explanation (“falling down”) already presupposes gravity in the first place. It’s a circular argument, as they explain gravity with gravity.

I’m sure the problem is in the analogy (not the science). So… can someone explain relativity’s account of gravity without faulty analogies?

32. Dolly Cagney says:

Einstein actually looked up to Michael Faraday. James Maxwell did the math to prove Faradays theories. That's the only issue with this video. Please don't erase one of the greatest scientists of all time.

33. Homieboy Seventeen says:

Still dont understand how movement changes time lol. You perceive things differently yes, but time is time… Constant. Maybe someone can help me understand this…

34. lövê íń thë ãïr says:

Time dilation : when we know the answer of every question in the exam but we've not enough time… That time,time seems moving very fast..

But when history teacher comes in the class the time seems moving so slow…

35. Juanco_"C.E.O." says:

I just got mind fucked.

36. TWSTF 8 says:

The speed of light is 298,792,458 meters per second.

The coordinates of the very tip of the Great Pyramid in Egypt are
29.8792458° N, 31.1342° E.

Coincidence?

TESLA knew that was just a bogus theory and that Einstein was a shill. That is why you never learned about TESLA in school. Instead we were taught the theories (assumptions) of Capernicus, Newton and Einstein to embed in your brain.
What ever you think is past, future or now -is all one happening.They are not three different geographical spaces. Actually what happened yesterday, what may happen tomorrow if you sit here and imagine all happen now,
isn't it?

38. mackenzie winter says:

4:00 how does time slow down when he divided it by two shouldn't he multiply it?as the slower time is the more seconds?

39. Izaya Evarez says:

The greatest knowledge to take from this was that my head is slightly older than my feet. I'm going to have to remember this one.

40. MrKronologi says:

I cant understand anything that you'd explained..

41. #whengamingmeets evil says:

does this prove that time can be slowed but not reversed

42. Sean 'nito Guidry says:

He almost had it. Time doesn’t slow down when moving away from an object at light speed. Its delayed but only to the travelers. Much like the delay of the light from the sun. Travel straight at the sun at the speed of light would make the sun brighter, while moving away will make it darker. Not because of distance but much like how sound waves work between a radio in a car with respect to someone standing on the sidewalk. As the car gets closer, the compacted waves cause it to sound faster, and as the car goes away it slows down. So when leaving the clock tower in reverse at the speed of light the clock will in-fact stop, but as soon as you stop traveling the clock would immediately start to catch up ONLY to the point of the delay caused by the distance. So lets say the clock would show only half the time it actually would be with respect to the traveler(relative to the same time back at the start). As you travel back to the clock it would catch back up to normal time(making both clocks match once again). No time traveling. Just traveling with light delay.

43. Sean 'nito Guidry says:

Time dilation? More like duration delay

44. Mr lemon lemon says:

Friend: Take your light speed car and go riding
Me: ok
5hour later
Me:Wow it had been 5 hours on my car
Friend: You mean by five years

45. Daniel Osko says:

PERCEPTION. All of these theories SEEM to based upon an individuals or an experiments PERCEPTION of TIME. I.E.; IF a Star was traveling at 99% percent of the speed of light, and the Star itself was emitting light AT the speed of light.., then if one was traveling with that star, (from their PERSPECTIVE), the speed at which light from that star moved would be at the speed of light . If however, one observed the speed of the star plus the light which it emitted.., from another individuals distant PERCEPTION the light that the star emitted would be traveling at nearly twice the speed of light. But since science is not based upon PERCEPTION. I believe that the actual speed of light emitted from the star would be nearly twice the speed of light. PLEASE correct me if, or DISPROVE me if I am wrong. THANKS!!! 🙂

46. Abid Farhan says:

Wait, this isn't about encryption and decryption.

47. Journey of RAM says:

"FASTER YOU MOVE THROUGH SPACE, THE SLOWER YOU MOVE THROUGH TIME." – watch on 2x speed, then you can save 4 minutes. 👍🏻

48. pigofapilot1 says:

Time-dilation means that nothing in space is where it appears to be. It is obvious if you think about it. We see the sun at the point in spacetime it occupied 8 minutes previously and sunlight (along with the information it carries) is 8 minutes old.

49. playaa playa says:

K but what makes the clock go slower when its moving really fast?? And how does he even know that

50. Ggt Afd says:

speed of falling from space to the earth is affected by air density not by time streching😂

51. Iziimz says:

If the tram car would travel at the speed of light, how the hell he still see the clock tower and suddenly stop moving from his perspective? Did he gain superhuman reaction time proportional to the speed of the tram car?

52. Abdelhalim Istikla says:

Took me couple of rewinds to grasp.

53. MTV BaNasty says:

So this is all wrong if what he said is true abt interstellar he said the gravity was so intense so they would just be moving slower witch wold make a second seem slower but if they were on there for what was an hour for them and 7 years on earth there body’s would still age

54. Wear Montgomery says:

((FAQ.))

55. chandler kendall says:

Weird I’m trying to figure out science and have to wait for some soda ad

56. pigofapilot1 says:

A fundemental principle of light in a vacuum is that it is not affected by time and space (spacetime). Only the wavelength (spectrum) of light changes relative to velocity. The same principle also applies to radio and other electromagnetic waves. Even light takes time to travel from A to B. Its velocity can be slowed by gravity and some other mediums (water for example) but its velocity cannot exceed 'c' in a vacuum. Therefore, because 'c' is a universal constant, time and space (spacetime) are variables relative to 'c'.

57. LifeSource -Minecraft says:

Is it normal that as a 12 year old I am already reading Einstein's translated book on the Special & General Theory of Relativity, take numerous notes on it, and discuss it with others?

58. Ethics hindulogy says:

First of all lets think there is no time so speed cannot be calucated is time if we are standing at or our earth is on 265 day and we want to go on 300 so we tooked a space sheep and tried to go forword of earth with particles of earth and after days the particles will grow or fungus or it will increase while moving forward of earth the then the time we move to 300 day and wating for earth to arrive….is it possible think once again moving in space is quiet big what will the influences and problem will we go to another field because of forces…look in another way.. subscribe my channel

59. Nello Kiko says:

A theory is not science.

60. aloha ne says:

Einstien is the reason i cant pass my phsics subject..

61. Jon Peniel says:

This is one of Einsteins dumbest theories. In order for something to distort space (like being on a huge trampoline), it would indicate that gravity must already exist in order to cause the "trampoline" to be pulled down in the first place. Then an object rolling around this trampoline would need gravity pulling onto the trampoline in order to move toward it's target with this newfound delusion of a whole new gravity. I mean WTF? Why are people so dumb as to go along with this crap? The whole key to discovering what is truly going on here is not some factitious stupid mind experiment that is dumb and pointless. It has to do with the relative expansion rate of space on a given distance. This expansion rate of unoccupied is different depending on the distance and time being measured but it remains constant mathematically but not constant with occupied space that has a different and slower equation (varied depending on the mass). Not only that.. this expansion rate has already been PROVEN beyond any hypothesis or theory and is visually observable and measurable. So what gives? Are people really this damned stupid? Why are we still relying on this idiot's theories? Put away the milk and start eating solid foods, children. Grow up!

62. Aaron Vlogs says:

This theory is stupid. Einstein….this doesn’t make sense

63. Josh Bojangles says:

How do you stretch a second if the moving photon of the falling man takes the same time (one second) to pivot as the observers’ photon clock?
When the man is falling, the distance traveled by the photon is greater because (falling) motion is added to the total distance.
The larger photon distance just proves the clock was in motion relative to a stationary clock.

64. Simple Art says:

Relativity is false. still a theory

65. The Imperfectionist says:

I never thought I’d say this but I think Einstein is wrong. Moving at the speed of light wouldn’t change time but rather your perception of when something happens. We forget that the way we see is light reflecting off of an object into our eyes. If the speed of light is a constant then yes moving at the speed of light would make a clock seem to stand still but this doesn’t move you through time at any faster a rate. The object is still moving but the light from the change in position wouldn’t have had time to reach you yet. I’d also bet that if you moved towards a clock at the speed of light then you’d see the hands move in fast motion. It’s all perception.

I’m not a physicist so this is a bit unrefined but I’d say a good calculation would be to find the light-distance between two objects and divide by light to (hopefully) find past-time or how far in the past we’re witnessing the object.

66. Nikita Kuznetsov says:

Ok I'm going to find a way to travel at 90% the speed of light and go to the year 2050 AD to find out if YouTube is still around by then. I better not be disappointed.

67. rrando99 says:

Great explanation of why time slows down near a massive object!

68. Syarz Asterisk says:

I walk using my hands upside down so my feet are older than my head xD

69. moniquelauren99 says:

What the heck

70. Dewey Tucker says:

Einstein was wrong about everything. He invited nothing, and holds no patents.

71. Real ish says:

Yea well, I hope present day physicists understand that this logic is flawed severely…just because the photons bouncing off the clock aren't reaching your retinas in real time, doesn't mean the actual clock has slowed down.

72. #DnA4lyfe Squa says:

Could humans have powers? I know it’s impossible but why?

73. Slices of SIB says:

To the universe, there is no TIME!

74. Ben Knight says:

So if Interstellar is to be believed, we could travel to the far future by hitching a ride through a wormhole, "relaxing" for a few hours on a planet that's near a black hole, and then take that same wormhole back to Earth.

In the second thought experiment, the man on the train will observe the lightning bolt closer to him first because that lighting bolt travels less distance. Not because it has more velocity… The velocity in both cases are same. It's just the distance factor that makes him observe the lightning bolts at different point of time. So, there is no dilemma. Newton's and Maxwell's laws are both being obeyed at least in this experiment. Correct me if I'm wrong. Highly appreciated.

76. Geethanjali balaji says:

77. KipIngram says:

Something about this feels off to me. It's not as simple as perceiving event A earlier than event B because A is closer. We have understood that notion for centuries. Time dilation has a more subtle complexity than that. That simple idea would still be true regardless of whether or not relatively moving observer measured different speeds for a light beam or not.

There's an adage, "As simple as possible, but no simpler." This treatment seems too simple to me.

78. W or L says:

Nice animation. Full of fictional theory crafting but entertaining nonetheless.

79. Yours Truely says:

So when i watch this video when traveling at the speed of light it will never finish??

80. Yui Nurahilyon says:

Can you fall in space or fall from space? I find it illogical to make the sentence fall in.

@5:57 isn’t it the time runs slower in the atmosphere than it does on earth? I don’t get it

82. Michael Smith says:

Boaring

83. Vaibhav Srivastava says:

Nice

84. Уαรïя Sαℓï๓ says:

Watches the whole video
Learns that my head is slightly older than my feet

85. Xplane 11 Fan says:

URTH IZ FLĀAAAT

86. Kirti Jakhmola says:

8:05

Me : one of your knee cap is slightly bigger than the other!

87. ORANGE CROSS GUY says:

time dilation is one of dota 2's void's skills

88. Suraj Kumar Mundra says:

Thanks to this video I took up Commerce

89. Rohitaswa Sarbhangia says:

is that the spaceship from Miller's planet, from Interstellar Movie….

90. Q R says:

Time theories are the biggest hoax doing the rounds.Makes no sense at all.

91. E L says:

so gravity is the outcome that make our 3D dimension curve?

92. Santosh Das says:

I need another video to understand this video🙆🙆🙆

93. Son Goku says:

I'm going to use this excuse to my wife after sex.

94. nederhood says:

Einstein could NOT see the clock if the train goes in 186 kilometers per hour 😁😜

95. abhishek v nair says:

Why they always say space time curvature and time slows down where gravitational pull is more.. I don't get it, actually space itself is curving under influence of matter isn't it… Clock near higher gravitational pull slows down for nano seconds because itself is matter isn't it…hence gravity influence matter and vice versa…. The actual concept of time is altered here isn't it… I don't know why physicists are so anxious about time dilation and so on… Can any one explain me whether I'm wrong..?

96. Unbiased Sports says:

So why do moons/stars spin backwards creating an angular problem?

97. Steven Baxter says:

@ 3.14 …. "the person on the train is moving at the speed of light"…. Have you got this wrong? Why does he have to be moving at the speed of light for this effect? if I am wrong then your explanation is poor so either poor or wrong!

98. Razer Loche says:

but just because you dont observe it doesnt mean your dont experience it?

99. Jason Shoraka says:

The beginning part of this video when Einstein is moving away from the clock on the train at the speed of light he says he would see the clock saying the same time, that's because the light reflecting from the clock saying 3 or 12 or whatever would follow him as he's moving the speed of light and he was T you still see that it's the same time in the clock, because the light reflecting the three would follow him as he's traveling the same speed of light away from the clock, same as taking a photograph have a clock showing 3 or 12 or whatever clock time and carrying the photograph of the clock with you as you were traveling, if the clock saying 3 or 6 or whatever time so that has nothing to do with time travel

100. Jason Shoraka says:

Towards the end of the video, the man in space the man falling from the sky and the man on the hill seeing this guy falling from the sky with the atomic clock with that one Atomic atom going back and forth, 1 views the atomic particle going back and forth faster then the other one sees it going back and forth slower, so what that tells me is one of them saw the atom or the particle going back and forth more times many more times back and forth then the other person in space which indicates parallel worlds, because from the point the person fell from the sky to the ground the atom going back and forth can only go back and forth so many times, but the other person viewed that the atomic particle on the atomic clock going back and forth many more times so that indicates parallel worlds, hence the parallel world theory not time travel, maybe that is all that exists is parallel worlds and not time at all!