I’m can’t grasp the concept of time dilation.

[GameOver]

I have been watching videos and readings articles but I'm still struggling understanding how time dilation occur.

I know that If an object moves 100mph while I'm standing still, the "real" speed of the object is 100mph.

If I'm moving 50 mph in the the same direction of said object, then the object is moving 50mph with respect to me.

The speed of light is constant so no matter how fast I'm moving(let's say 90% of speed of light) the speed of light with respect to me will always be 186282mps and that's were I get lost.

Help me

 

[GoodFun_HaveLuck]

I think the key thing to recognize is that time does not move slow for you as far as your mental awareness of time goes.

If you're on a rocket going so fast that time is moving at 1/10th if it's speed compared to being on Earth, you don't feel this. A second still feels like a second. It's just that the time you observe to have passed when you get off the rocket will be different than what others observed.

 

[Ricky_R]

Let me watch Interstellar again and I'll get back to you.

 

[Dreams-Visions]

Let me watch Interstellar again and I'll get back to you.

Click to shrink...

pls no

 

[808s & Villainy]

Watch Gunbuster. They give an explanation of it
And it's excellent

 

[Deleted member 24540]

The speed of light is constant so no matter how fast I'm moving(let's say 90% of speed of light) the speed of light with respect to me will always be 186282mps and that's were I get lost.

Help me

Click to shrink...

There is a formula:

Distance = Speed * Time

What happens is since the speed of light stays the same, then time must change in order to match the same distance, hence time dilation.

 

[Saganator]

 

[Senator Toadstool]

let me introduce you to weed

 

[JonnyDBrit]

I have been watching videos and readings articles but I'm still struggling understanding how time dilation occur.

I know that If an object moves 100mph while I'm standing still, the "real" speed of the object is 100mph.

If I'm moving 50 mph in the the same direction of said object, then the object is moving 50mph with respect to me.

The speed of light is constant so no matter how fast I'm moving(let's say 90% of speed of light) the speed of light with respect to me will always be 186282mps and that's were I get lost.

Help me

Click to shrink...

You ever heard of the Achilles paradox?

The idea, as usually explained, is the notion that Achilles, if restricted to only move at the same time a tortoise does, will never be able to catch it. This breaks down if that restriction is immediately gone, since if Achilles keeps going, he will of course catch the tortoise.

So imagine then that reaching the tortoise is your experience of one second of time passing. While the tortoise - you - moves slowly, Achilles - any action occurring to you in time - will catch up. But, Achilles has a speed limit - he can't go faster than light. So if the tortoise reaches say, half the speed of light, then from an external perspective, it's going to take a hell of a lot 'longer' from Achilles to catch it - it won't escape forever, but Achilles has to travel a much farther distance to reach it. But until Achilles reaches it - until it reaches you - from the tortoise's perspective, a second has yet to pass. The faster the tortoise gets, the further Achilles must run to catch it; the greater the experience of time dilation. The 'less' time you experience, versus everyone else.

 

[Freezasaurus]

Man, I read a sci-fi novel once that used this concept to age up a little girl the main character had met into a romantic interest. Shit was kinda weird.

It was this one, for the curious.

I mean, I enjoyed the book a lot, otherwise.

 

[808s & Villainy]

let me introduce you to weed

Click to shrink...

Weed for me is more like

 

[gdt]

You ever heard of the Achilles paradox?

The idea, as usually explained, is the notion that Achilles, if restricted to only move at the same time a tortoise does, will never be able to catch it. This breaks down if that restriction is immediately gone, since if Achilles keeps going, he will of course catch the tortoise.

So imagine then that reaching the tortoise is your experience of one second of time passing. While the tortoise - you - moves slowly, Achilles - any action occurring to you in time - will catch up. But, Achilles has a speed limit - he can't go faster than light. So if the tortoise reaches say, half the speed of light, then from an external perspective, it's going to take a hell of a lot 'longer' from Achilles to catch it - it won't escape forever, but Achilles has to travel a much farther distance to reach it. But until Achilles reaches it - until it reaches you - from the tortoise's perspective, a second has yet to pass. The faster the tortoise gets, the further Achilles must run to catch it; the greater the experience of time dilation. The 'less' time you experience, versus everyone else.

Click to shrink...

what's that's bruv

 

[AlgusUnderdunk]

I went to the chronometrist's today and they time-dialated my eyes.

I can see faster now.

 

[Senator Toadstool]

Weed for me is more like

Click to shrink...

that's alcohol for me. it's why i don't drink anymore. too many forgotten nights 🥴

weed i'm good with

 

[Poltergust]

You ever heard of the Achilles paradox?

The idea, as usually explained, is the notion that Achilles, if restricted to only move at the same time a tortoise does, will never be able to catch it. This breaks down if that restriction is immediately gone, since if Achilles keeps going, he will of course catch the tortoise.

So imagine then that reaching the tortoise is your experience of one second of time passing. While the tortoise - you - moves slowly, Achilles - any action occurring to you in time - will catch up. But, Achilles has a speed limit - he can't go faster than light. So if the tortoise reaches say, half the speed of light, then from an external perspective, it's going to take a hell of a lot 'longer' from Achilles to catch it - it won't escape forever, but Achilles has to travel a much farther distance to reach it. But until Achilles reaches it - until it reaches you - from the tortoise's perspective, a second has yet to pass. The faster the tortoise gets, the further Achilles must run to catch it; the greater the experience of time dilation. The 'less' time you experience, versus everyone else.

Click to shrink...

Did I just step into a Zero Escape game

 

[SilverArrow20XX]

The speed of light is constant so no matter how fast I'm moving(let's say 90% of speed of light) the speed of light with respect to me will always be 186282mps and that's were I get lost.

Help me

Click to shrink...

So, say you fire a gun from on top a train going 100mph.
And another from a car moving 50mph.
The bullet from the train will be moving 50mph faster than a bullet fired from the car, from the perspective of a person watching from the ground, who sees themselves as stationary. Relatively speaking.

Light is constant.
So if you shine a flashlight from the train, it does not get 100mph added to its speed.
The observer from the ground will see both the car and train light beams as the exact same speed.

So if you are going 99.9999999% the speed of light, and shine a flashlight ahead.
It will be like it just stays with you, or moves forward at a crawl.
Or anything really. If you try to throw a ball forward at that speed, you're throwing speed won't be able to be added to it.
It'll "stop" instead.
Time dilatation allows for this fundamental law to not be broken.

 

[JonnyDBrit]

Did I just step into a Zero Escape game

Click to shrink...

I don't know if I should take that as a compliment or not, considering I've not played that

 

[andymcc]

watch Gunbuster!

 

[Senator Toadstool]

Seriously though once you grasp relatively it all makes sense

Einstein figured this out in the 1910s or so

 

[Poltergust]

I don't know if I should take that as a compliment or not, considering I've not played that

Click to shrink...

Pretty frequently in these games, a character would take you aside and ask you things like "have you heard of Schrodinger's cat?" or "do you know about the Monty Hall problem?" and then explain in extreme detail about what that's all about lol.

 

[Deleted member 24540]

Here's another way to think about it. Ignore the earth and the rocket. Just look at the red arrows and ignore everything else basically.

In the first image, imagine you are in a train and the black bars represent mirrors that you place in the ceiling and the floor. You shine light that bounces back and forth in the mirrors. The distance traveled of the light from one mirror to the other is distance = speed of light * time or more compact d = c*t

In the second pic, you are watching this unfold from a park bench looking at the train going past you. What you will notice is that the light doesn't travel up and down anymore, but the path is diagonal, since the train is moving forward so the light will travel in this pattern, which means that the distance light travels for the person from the outside looking in is actually larger.

But remember, we assume that the speed of light is constant. So what are the consequences of that? Just look at the formula: d = c*t. Since the distance is different depending on if you are on the train or outside looking in, then it must mean that the time a person ON the train measures is different from the time the person who is OUTSIDE measures, otherwise the equality would collapse. This is the meaning of time dilation... it is based on the assumption that the speed of light is the same no matter who measures it.

 

[Xe4]

PBS Spacetime did a good episode about it, including Minkowski diagrams and everything.
I believe it is this one:

---

Edit: It was this video, but the Sixty Symbols video a few posts below mine makes the same point and correctly stresses the importance of the Pythagorean theorem in special relativity.

 

[GameOver]

And another fucking my head it's this

A new born baby departs from earth to a planet 5 light years away on a ship that can reach the speed of light. When the new born baby comes back to earth he/she still a baby and not a 10 year old kid? So his/her biological aging was slowed down right? So if the baby has a twin, the twin that stayed on earth is 10 years….

 

[Senator Toadstool]

Here's another way to think about it. Ignore the earth and the rocket. Just look at the red arrows and ignore everything else basically.

In the first image, imagine you are in a train and the black bars represent mirrors that you place in the ceiling and the floor. You shine light that bounces back and forth in the mirrors. The distance traveled of the light from one mirror to the other is distance = speed of light * time or more compact d = c*t

In the second pic, you are watching this unfold from a park bench looking at the train going past you. What you will notice is that the light doesn't travel in a straight line, but the path is diagonal, which means that the distance light travels for the person from the outside looking in is actually larger.

But remember, we assume that the speed of light is constant. So what are the consequences of that? Just look at the formula: d = c*t. Since the distance is different depending on if you are on the train or outside looking in, then it must mean that the time a person ON the train measures is different from the time the person who is OUTSIDE measures, otherwise the equality would collapse. This is the meaning of time dilation... it is based on the assumption that the speed of light is the same no matter who measures it.

Click to shrink...

very good explaination

 

[Popstar]

This is the clearest explanation I've ever seen, but requires a tiny bit of math (the pythagorean theorem)

 

[brinstar]

I believe it's the faster you move through space, the slower you move through time. so if you blast yourself through space at near-light speed for what feels like a few hours, a lot more time will have passed for everyone else on earth.

 

[samoyed]

Everything you think you know about time is wrong and is a shorthand we invented for monke brains.

When you're moving at 0.9c (from the POV of an observer) and you switch on a flashlight, the light from the flashlight is moving at 0.99c with respect to you, not 0.9c + 0.99c, which is what you'd expect under naive physics. The issue is you think it is possible to move at 0.9c by yourself. The claim 'i'm moving at 0.9c' implies the existence of a third party (observer) you're moving relative to, then the light from the flashlight is moving relative to you (the observer of the flashlight becomes you in this case). I forgot what the observer sees of your flashlight, I believe it is still moving at 0.99c with respect to observer. How can something move at 0.99c in multiple different frames of reference? Fucking relativity and shit.

Just stop trying to add numbers together at relativistic speeds, it doesn't work. Naive arithmetic only works and makes intuitive sense at fractions of c.

I know that If an object moves 100mph while I'm standing still, the "real" speed of the object is 100mph.

Click to shrink...

No, don't think like this. This is why you are struggling. You, like most people, think "speed" is a real thing and that velocity/speed/momentum at 100mph works the same way in your car as the speed of light does at 186,000 mps, just a lot faster. And that is untrue. The laws of motion do not scale linearly like this. Everyday 'speeds' and relativistic 'speeds' operate in entirely different ways, do not let the shared labels fool you into thinking you can just multiply mph by really large number to understand relativity.

It took the collective brain power of humanity 2000 years to figure this out. It is an entirely unintuitive concept, so you need to abandon intuition and just trust in the math, which is not 'x + y' but:

 

[Senator Toadstool]

And another fucking my head it's this

A new born baby departs from earth to a planet 5 light years away on a ship that can reach the speed of light. When the new born baby comes back to earth he/she still a baby and not a 10 year old kid? So his/her biological aging was slowed down right? So if the baby has a twin, the twin that stayed on earth is 10 years….

Click to shrink...

op i think your high

 

[Jedi2016]

 

[Emwitus]

So, say you fire a gun from on top a train going 100mph.
And another from a car moving 50mph.
The bullet from the train will be moving 50mph faster than a bullet fired from the car, from the perspective of a person watching from the ground, who sees themselves as stationary. Relatively speaking.

Light is constant.
So if you shine a flashlight from the train, it does not get 100mph added to its speed.
The observer from the ground will see both the car and train light beams as the exact same speed.

So if you are going 99.9999999% the speed of light, and shine a flashlight ahead.
It will be like it just stays with you, or moves forward at a crawl.
Or anything really. If you try to throw a ball forward at that speed, you're throwing speed won't be able to be added to it.
It's "stop" instead.
Time dilatation allows for this fundamental law to not be broken.

Click to shrink...

Its sounds like you described an invisible wall in god of war.....by which I mean it still boggles my mind why the universe or specifically light has a speed limit. Why? why doesn't a photon go faster as it moves through a vacuum if it's weightless? I don't get it. Although I guess I might have answered my own question since nothing can technically affect it as it moves along due to it's weightlessness other than the gravity of a black hole. But even light bending around a black hole won't go any faster Ala ships using gravity assist around planets.

I digress

 

[Aurongel]

I think you're missing the concept of consciousness and perceptual awareness being affected by this. As you "slow down" relative to distant observers, your awareness and conscious perception seem unaffected from your perspective. But looking outward, you'd see everyone watching you moving at an impossibly fast speed.

 

[JonnyDBrit]

And another fucking my head it's this

A new born baby departs from earth to a planet 5 light years away on a ship that can reach the speed of light. When the new born baby comes back to earth he/she still a baby and not a 10 year old kid? So his/her biological aging was slowed down right? So if the baby has a twin, the twin that stayed on earth is 10 years….

Click to shrink...

Then the twin on Earth is ten physically and by our measure, while the twin back from space is physically a baby, and from their perspective has experienced next to nothing in terms of time, while to observers on Earth, ten years have passed.

 

[Rassilon]

It just occured to me that a hypothetical colony on Mars would experience time slightly differently because Mars moves slower than Earth.

right?

 

[JonnyDBrit]

It just occured to me that a hypothetical colony on Mars would experience time slightly differently because Mars moves slower than Earth.

right?

Click to shrink...

Yes, but not enough to significantly affect communication and interaction between the two planets. In much the same way that astronauts in orbit right now age ever so sliiiiightly slower than those on Earth.

 

[Emwitus]

It just occured to me that a hypothetical colony on Mars would experience time slightly differently because Mars moves slower than Earth.

right?

Click to shrink...

Even our own satellites a couple of hundred km above the earth experience time differently. I assume gravity on mars would play a part as well.

 

[Rassilon]

Yes, but not enough to significantly affect communication and interaction between the two planets. In much the same way that astronauts in orbit right now age ever so sliiiiightly slower than those on Earth.

Click to shrink...

Even our own satellites a couple of hundred km above the earth experience time differently. I assume gravity on mars would play a part as well.

Click to shrink...

 

[JonnyDBrit]

Click to shrink...

Username proving pretty ironic right now

 

[GameOver]

Then the twin on Earth is ten physically and by our measure, while the twin back from space is physically a baby, and from their perspective has experienced next to nothing in terms of time, while to observers on Earth, ten years have passed.

Click to shrink...

But the people on earth will see the traveling twin as a baby while the other twin as 10 year old, right?

 

[samoyed]

by which I mean it still boggles my mind why the universe or specifically light has a speed limit. Why?

Click to shrink...

Why does blue look like blue and not red? It is a meaningless question. c is what it is because the universe would not function the way it does if c was higher or lower, it would be an entirely different universe and emwitus in the 'c = 299 792 457 m/s' universe is probably asking 'why is c = 299 792 457 m/s and not c = 299 792 458 m/s?'

 

[Mass One]

I'm still trying to process that episode of static shock where at the end the guy is trapped running away from static shock. The catch is the time thingy where static looks like he's moving fast but really the dude is just really slow. I'm pretty sure static shock said it'll take him a whole year to get to the end of the street or whatever.

 

[Emwitus]

Why does blue look like blue and not red? It is a meaningless question. c is what it is because the universe would not function the way it does if c was higher or lower, it would be an entirely different universe and emwitus in the 'c = 299 792 457 m/s' universe is probably asking 'why is c = 299 792 457 m/s and not c = 299 792 458 m/s?'

Click to shrink...

You can explain why something is blue...(wavelength Bla Bla) but its not easy to explain away why there is a limit to the speed of light. Its not a meaningless question. The whole point of physics is to explain away fundamental things. You giving a speed of light and saying its meaningless why its not a digit lower or higher doesn't change the fact that no one can tell you why the limit of the speed of light is what it is. \

Having said that, you do bring up a good point. The universe wouldn't work the way it works the way it does with a different speed. And if multi dimensions are a thing then for sure the emwitus over there is asking this very question.

I just find it fascinating that we have a virtual speed limit. No FTL no inter-galactic travel for us.

 

[JonnyDBrit]

But the people on earth will see the traveling twin as a baby while the other twin as 10 year old, right?

Click to shrink...

Yes, though because of its speed, they wouldn't be able to have a functional conversation with it, or anyone else aboard the ship (since, y'know, baby). It would seem frozen in time to them, beyond its movement through the universe at large

Edit: To put it another way, put two movies on at the same time. But you have one play at 1/8th speed, the other at regular speed. For you, the viewer, you can watch both for two hours of your time. But the movie playing at 1/8th the speed will only be up to 15 minutes worth of content

That is life at relativistic speeds, though the math as to the effect of the time dilation is a lot more complicated

 

[Jilvune]

Just to blow your mind some more:

 

[Kinthey]

Man, I read a sci-fi novel once that used this concept to age up a little girl the main character had met into a romantic interest. Shit was kinda weird.

It was this one, for the curious.

I mean, I enjoyed the book a lot, otherwise.

Click to shrink...

The Forever War uses time dilation to great effect. Main character is a 50 year veteran in no time while in his perceived time he only served a couple of years

 

[Tuorom]

Click to shrink...

What (also) blows my mind is how people come up with these equations

like how do they know to square variables? and then find the root like I don't understand but I guess I'm not seeing all the progress and work.

 

[Joe Shlabotnik]

You can explain why something is blue...(wavelength Bla Bla) but its not easy to explain away why there is a limit to the speed light. Its not a meaningless question.

Click to shrink...

Well it's more like the "speed of causality", and light travels at that speed. It's not related to light itself at all. Nothing happens faster than causality—there has to be a limit because you can't have an effect before a cause.

 

[Trey]

It's all right, it's not meant to be grasped.

 

[AGoodODST]

Yes, but not enough to significantly affect communication and interaction between the two planets. In much the same way that astronauts in orbit right now age ever so sliiiiightly slower than those on Earth.

Click to shrink...

Wait, isn't it the other way round? Astronauts age faster as they are further away from the effect of Earths gravity.

edit: no you are right im forgetting they are also zooming around Earth lol

 

[PennyStonks]

Faster you go slower go time.

 

[TheSkullPrince]

I can't understand it either no matter how many YouTube videos I watch on the subject lol

There was a thread here a few months ago where the OP finally realized how time and space were…connected or some shit and yeah it all went over my head.