Being more specific, if you're traveling at a speed at which 1 year for you is 10 years on Earth, would your body age 10 years? Why or why not?
So this is time dilation. So we'll go into the tool box and get some identical twins.
Twin 1 stays on Earth.
Twin 2 gets on a light speed rocket where the time dilation is 10:1.
When this starts They are both twenty years old.
Ten years pass on earth. Twin 1 is now 30 years old. Twin 2 lands their ship and they are 21 years old.
Yeah, time dilation is kind strange.
But both experience time moving at a constant speed and see the other twins time moving faster or slower then their own. The 21 year old twin doesn't feel like he's loved 10 years, he only feels one year had passed and, for him, that is true
What a life it would be to love for 10 years… I envy that twin and their cosmic adventures of love
Cosmic incest
...see the other twins time moving faster or slower then their own.
They both see the other moving through time slower than themselves. In each of their frames of reference they are the ones which are stationary, and the other party is moving relative to the their frame of reference.
When they come back together again, the reason their ages don't match or the universe hasn't collapsed into a paradox is because they experienced different accelerations at different times which makes the math way harder to understand.
Would Twin 2 be able to navigate their ship to a far away distance and back and the time dilation would still remain 1 year? Like does slowing down or changing direction affect how the two twins reconnect?
It could. Things get funny when you get into speeds that have time dilation that is observable to people and not instruments.
Yes. Acceleration is precisely what breaks the symmetry of the twins' age. Accelerating frames are not inertial frames of reference. Special relativity (the space contraction and time dilation we are talking about here, which is based on Lorentz transformation) only applies to inertial frames of reference. When a frame of reference undergoes acceleration (the twin on the rocket) you need to go to general relativity, which is far more complicated.
I have heard it's the speed.
In the case with the GPS satellites, does that mean that the time skewing happened the first moments during launch?
No. GPS satellites experience time dilation due to their distance from Earth and the speed of their orbit. You are always accelerating when moving not in a straight line so satellites aren’t in an inertial reference frame.
For another take on this: ‘39 by Queen:
Your body would age 1 year because one year for you is one year of your body doing stuff and existing.
Space and time are actually just two aspects of the same thing, spacetime. So when you move through space you also move through time, and if you are moving at a some speed compared to someone else you also move through time differently. Wherever you are time is always locally passing at the normal rate, everything feels normal, but for someone in the Andromeda galaxy they will be counting off the seconds at a different rate because they are moving towards us.
How does gravitational time dillation play into this?
Going deeper into a gravity well your clock slows down compared to those not deep down a gravity well. General Relativity models both effects. Special relativity only captures the speed one, but it is a lot simpler math.
How does it fill within the formula of someone slowing down through time because they move faster through space? Like, if something is moving through space at 99% of speed of light, and it is also deeper in the gravity well relative to something else, then it moves slower through time based on both those effects? What about something moving at 99.9% c, and also being in the gravity well, are there diminishing returns or is my logic at fault?
So key thing, you always feel locally like time is flowing at a normal speed for you. The odd thing is that if you were to look at some very large clock that was somewhere in a different situation from you, it would look like it is ticking at a different rate.
Moving through space, there is no absolute reference frame, meaning there is no totally true answer about who is moving or who is still, only a relative speed between things. So if you are still compared to the ground, a clock you hold and a clock on the ground will seem to tick at the same rate. Clocks on sattelites in space zooming past at 7 kilometers a second will tick at a different rate from clocks on the ground. Both are correct in their own frame, someone on the sattelite can juggle or play ping pong and everything feels normal to them, but when they send radio pings to the ground every second on their clock, they arrive at a slightly different but measurable time period than one second apart.
And yes, the gravity and speed effects combine. How exactly I can't say, the math is very complicated and I can't do it currently. It is solving a differential equation in a multi-dimensional matrix, also known as a tensor.
yup this and time likes to follow the simplest path aka geodesic , being on earth its basically a free fall , but on higher speeds time experiences a difficult path reaching you , hence you age less. ( this is how i like to explain myself lol)
Time always passes for you at 1 second per second. How much time passes at another location is irrelevant for your question.
The answer to your question is you would age by 1 year as that is how much time passed for you.
Your body would only age 1 year in this situation. Time is passing slower for everything that is traveling with you. This includes your spaceship, the food you brought, and the cells in your body. You would only age 1 year because this is the amount of time your body experiences. If you travel in a big loop and come back to Earth, you would be 9 years younger than everyone that stayed on Earrh.
I would say my biggest doubt is how exactly all those biological processes slow down with the speed, that just never made much sense to me
They don't slow down relative to each other; from the point of view of the biology in question, everything is happening the way it always does.
You only get into a situation where time dilation impacts biology that way if there's some kind of large gradient due to general relativity, like the gravity of a black hole... And in that case, the time dilation on the biological processes doesn't matter because the biology in question is rapidly becoming physics--- it's getting ripped apart atom by atom by the massive gravitational shear across a very small distance in space.
Becoming spaghetti does make biology much less important lol
The biological model's relevance is diminished when all the molecules that need to interact with each other are now on their way to separate destinations, is the thing. It's like wondering what a heart does when exposed to an atomic bomb blast at one meter from origin.
Your time isn't slowing down, there is no such thing as absolute time for yours to "slow down" in relation to, it's all relative. By going on that spaceship ride you're not slowing your time down to 10% of Earth's time, from your perspective time passes perfectly normally and Earth's time will instead appear to speed up.
Yeah this makes sense when you guys explain it, I guess in my head cells would just have an internal clock of sorts, but that makes no sense at all.
You and your cells, and your brain, and your mechanical watch, and your digital watch, and your video game console, and the food in your space ship all follow the same rules of physics :)
You can argue that chemical processes are a sort of internal clock, since they happen at a certain rate. And that is the point. The cells are moving and so in their frame of reference time is slower than it seems to be for someone looking at them from Earth. If time is going slower, so the internal clocks run slower. Since the clocks are the chemical processes, and it is the chemical processes that make the cells age, so the cells age more slowly*.
*As viewed by someone looking at them from Earth
Cells certainly do have internal processes that work like clocks, and they run at the same rate as all the other clocks on the spaceship. The outside world's rate is irrelevant. In your example, all the biological processes behave as if just one year has passed - which it has, for everything inside the spaceship.
Imagine that you play an ordinary movie off Netflix but on slow-mo. When you watch the characters on this screen they’re moving slowly, walking slowly, aging slowly, thinking slowly.
It’s exactly like that.
If the cells have an internal clock (which they kinda do) they are slowed down too. Everything slows down.
Your local time doesn't change so everything still happens at 1 second per second. Higher gravity and/or speeds just make your local time happen faster than other areas, it's all relative.
GPS satellites have extremely accurate atomic clocks and still need to get synchronized every day due to the 1. Zipping around at 7000mph around the Earth and 2. Even though all of the satellites are 'just' in orbit around Earth, they still drift from each other a bit by being in different areas of space which have a slight difference in gravity and other factors
I think you're mistale is that you are thinking that the person travelling fast is only "perceiving" time moving more slowly. You are still stuck in thinking that time moves at a certain speed, and only our perception changes, and are confused as to why and our cells would slow down to match our perception.
But this is not what is going on. Time is not constant. When you experience relativity, it's not that your perception of time slows, it's that time itself literally slows down. You perceive the time the same as you always do, the time itself is just slower. So your cells move and age through time the same as they always do, it's just that the time itself is slower, so relative to someone not moving, your cells would seem to age more slowly. But they don't actually slow down.
You're right, reading all the replies so far in the post I can ser that that is definitely the case, getting some misconceptions out of your head can be just as difficult as learning something new entirely I suppose.
Imagine you are in a spaceship orbiting around the earth. Your spaceship is very fast, fast enough that relativity applies and your time is moving at 1/10th the speed of Earth’s time. For you inside your spaceship everything feels normal. If you have a clock inside your spaceship you might look at it and wake up every day at 6AM, eat at 8AM, 12PM, and 5PM, and fall to sleep at 10PM. Just a normal day inside your relativistic spaceship.
If you had a powerful telescope and could look down on the earth, everything would look turbo charged. You would see the earth rotating every 2.4 hours (instead of once per day) if you could see people walking, they would look like the fastest sprinters alive. Their time on Earth is just moving faster than yours.
Similarly, if your Mission Control team on earth could look through the window of your spaceship and see you, they would think you are moving at a snail’s pace. Watching you eat breakfast, an activity that usually takes 30 minutes, would take 5 hours.
So it’s not that your biological processes speed up or slow down, it is that the rate time passes itself changes. At relativistic speeds, you can’t trust an hour to be an hour. For you it might be an hour, but for someone watching you in your ultra fast spaceship it would be much longer. Hope that helps.
Time dilation doesn't mean the physical clock spins its hands at different rates, it means that the clock, you and everything around you experience time at a different rate to the rest of the universe.
Your clock appears to run at the correct speed the whole time, It's just that when you compare notes with the clock you left back on earth you'll find they disagree on how much time has passed.
If you spend a year of subjective time at relativistic speeds and come back to find 10 years has passed.
You have aged 1 year, your family has aged 10.
If however you could set up a clock which was synced to Earth Time (You know how fast you're going and how to calculate Earth-Time, you can do the math) while you went to Relativistic speeds, the hands on that clock would appear to rev up to 10x normal speed, covering a minute in 6 seconds, and an hour in six minutes.
The clock itself wouldn't age any faster than normal, it'd just spin faster.
No, you would by all measurments experiance 1 year of time. Its because actual physics experiance time dalation. But from your perspective everything will be normal. Can watch this vid to understand how that happens https://youtu.be/Vitf8YaVXhc?si=xkab3eacPBBP2laF
This video was actually really helpful! Never ocurred to me that biological processes would take longer because all the molecules and atoms would have to take longer paths, thanks!
Yeah this vid really helps you click. There is no magic, actually ineraction is logically derived. Just like Einstein did back in 1900s
Time dilation is measurable from ground to orbit.
Astronauts on the ISS experience time slightly differently to those on the ground. The twins, Scott and Mark Kelly were born 6 seconds apart, after Scott spent time on the ISS whilst Mark stayed dirtside, the difference is now +5ms
The further / faster you go, the more pronounced that dilation is
No you experience time according to your own reference frame so if only a year passes for you then you only age a year. Other reference frames don't affect your own even if thousands of years pass in a different one. If you only experience one year of time passing then that's how much you age.
Time is what clocks measure, and aging is a kind of biological clock. You'd age 1 year, because that's the amount of time that would pass in your reference frame.
You only ever experience time normally in your own reference frame. Your body doesn't "know" how much time is passing elsewhere. If you are holding a clock and 1 hours ticks, you've aged 1 hour. If you hold that clock for 10 years, the clock will show 10 years have passed and you will have aged 10 years.
If you are experiencing 1 year, the rate of time that earth or saturn or the black hole at the centre of the milkyway is irrelevant to you and your body's perception of time, which is 1 year
Absolutely. If identicals twins were sent into space one travelling at a speed where those conditions apply they'll come back with one having visibly aged a lot more than the other. That's why it's so interesting to us, it's not just our perception of it but a real time dilatation. There is no one "true" time in the universe.
i would like to present it in this way: you age in ways time reaches to you , if time ''takes'' time to reach you , you age slowly so you travelling at that speed will make you just age slowly because time will be following an extreme complex path (geodesic) to reach you.
yes. The closer you traveled near relativistic speed, the bigger the effect.
Normally muon particles that produced in the lab last around 2.2 micro second before decaying. But on earth surface we still detect muon particle created from cosmic radiation bombard the upper atmosphere, despite the fact it would take them too long to reach the surface before decaying. Due to relativity, from the earth surface's perspective they live longer than should. But from the muon's perspective, the length need to travel to surface has shrink so it can reach the surface before decay.
Aging is just a function of time, so if time changes so does aging.
The relativity twins was explicity explaining this. https://en.wikipedia.org/wiki/Twin_paradox
Aging isn’t about time it’s about the quality of your body and its degradation. But things degrade over time so they’re not really relative but like they say correlation isn’t causation. But to actually answer your question no. It’s why if you have a twin and travel light years away and return but at the speed of light you would be younger than your twin and have not aged as much either
Why would your body age 10 years? I apologise but your question doesn't make sense to me. When we say that an observer A experiences 1 year in space for every 10 years for an observer B on earth, we do not mean this in a psychological manner. They literally experience time in this manner with reference to each other.
When they meet again, 10 years would have passed for observer B and their cells would be 10 years older. However, 1 year would have passed for observer A and their cells would be 1 year older.
It is important to remember that this is only in reference to each other. Observer A and B both live normally throughout this period at 1 second per second. The difference being, the length of A's second is longer according to B. In their own reference frame, time passes normally, and the difference in the length of time only occurs when we compare different reference frames.
Maybe a simpler way to think of it is all time is local: the amount of time everyone has experienced is unique to them. For us humans on earth, it more or less matches up. But if you accelerate or decelerate significantly more than other people, your “clock” changes enough to notice.
you know that training room goku goes into and trains for 1 year while only 1 day passes on earth? Its like that. Goku would age by 1 year (because thats how much time passed for him) and everyone else ages 1 day.
Now replace the hyperbolic time chamber with just "someone moving very fast relative to you" and its the same thing (just in reverse, goku would be "stationary" while everyone else moves really fast)
You would age 1 year. Aging is linked to the amount of time experienced. The ticking of your physical clock controls how fast processes in your body run, and that ticking happens slower for a clock whizzing through the fabric of spacetime at high speed. We think of heartbeats as "beats per minute", but they're actually "beats per 60 ticks". If you go whizzing by someone on Earth, rather stationary in their local spacetime, you'll have 1/10 as many heartbeats, 1/10 as many bowel movements, 1/10 as many blinks, and 1/10 as many thoughts. Your lifespan will be 10x as long as it would've been on Earth, but you'll still experience the same number of ticks, heartbeats, blinks, and burps.
If you're moving at light speed, you age at light speed. If you're moving at Earth speed, you age at Earth speed. There's no one universal speed at which time flows anymore than there's one universal speed that cars move at.
Yes, but It would be the other way around, you would look younger, only a year would pass in your body.
Time is the same, it's how you feel it that makes the difference, that is "relativity"
We measure time as earth spins/rotations (days) or years (a completed sun orbit). If you never spun or orbitted but instead moved perpendicularly to the sun you'd still age, but the measurement would have to be something else. The formula remains the same, but the units change. T(ime) = D(istance) / V(elocity)
You already answered the question yourself. One year has passed for you on the ship. Why would you age 10 years? If that happened, it would be 100 years on Earth.
Ofcourse. Any physical process including life will follow relativity
Your body ages at the time you 'experience' it - ie. 1 year
Because under relatively, everything is relative to the speed of light
Aging is indeed relative.
They've done experiments with atomic clocks that desync when one is taken either far away from gravity(one type of relativity iirc) or if it travels at very high speeds(another type/part of relativity) ie if they fly it off into space and back.
The amount they fall out of sync by is usually very very small and such a small amount of time humans wouldn't even notice it consciously without measuring but they have done/tried it.
Iirc they have actually also done similar studies on biological twins and found tiny differences in measures of their aging when exposed to this high speeds/further distances from earth's gravity.
Aging is a direct result of the passage of time. If you only experienced 1 year, then you will only age 1 year. Everyone who remained on Earth experienced 10 years and would have aged 10 years.
Let’s say you have 2 twins Andrew and Bob. Andrew is on a spaceship travelling away from Earth at the speed of light, Bob is still on Earth.
Pretend for the sake of argument that they can still see each other what would they see?
Andrew would see Bob moving around really fast like watching a YouTube video on 10x speed, even though in the spaceship everything would seem normal.
Bob would see Andrew doing everything on board his spaceship at an absolute snail’s pace.
The faster you move, the less “time” you experience. So Bob would experience a full 10 years in the same span as Andrew only experienced 1 year. Einstein predicted this effect, and we have measured it directly using very precise coordinated atomic clocks on Earth and on satellites. In fact GPS navigation has to correct for time dilation between Earth and the relatively faster moving satellites!
Your body would age at the rate time is passing for you. Earth time isn't some definitive time reference. If it's 1 year for you then your body ages for 1 year regardless of how much time passes in any other reference.
You could clap your hands 10 times right now in 10 seconds according to the stopwatch on your phone and somewhere in the universe there exists a frame of reference where what you just did took 10 years. 10 literal years, one second per second, for 10 entire years worth of seconds.
And just like you were 100% correct that your 10 claps took 10 seconds, the other perspective is 100% correct that your 10 claps took 10 entire years worth of seconds, because there is no such thing as a “true” amount of time that fills a second. It depends entirely on the perspective you’re choosing to take when you begin to watch what happens.
Understanding relativity and time dilation is all about understanding perspective. You have to get into that headspace of thinking about perspective in order to have that aha moment that makes it really click. There is no such thing as the “true” perspective through which everything is “actually” happening in the universe. That doesn’t exist. There is only what each individual perspective observes and measures and sometimes those will be different. If you try to “zoom out” to take on the perspective of what is “actually” happening in the universe then all you’ve really done is plucked an arbitrary perspective out of thin air that isn’t any more or less special than the ones which well and truly measured your 10 claps to take 10 seconds or 10 years.
What the fuck this just blew my mind.
yes this is it! perspective is such an important concept – this video does what I think is an amazing job at simplifying the idea of time dilation
We love a good bit of relativity of simultaneity. The ladder does and does not fit into the barn.
Question for you.
If someone uses speed for time dilation like planet of the apes, why can you treat the earth and ship as moving away from eachother instead of the ship going fast and the earth slow?
I’ve never watched Planet of the Apes, but I’ll try to answer this
Something needs to happen for 2 perspectives that are previously in sync to diverge, and vice versa.
Someone has to accelerate.
And while there is no such thing as absolute time, space, or speed; there is such a thing as absolute acceleration.
And acceleration slows time.
Because the Earth and ship are moving away from each other. From the perspective of the Earth it’s the ship that’s moving away from Earth. From the perspective of the ship it’s the Earth that’s moving away from the ship. Both of them are moving relative to the other and consequently both of them would view the other’s clock ticking slower than the other.
It’s an unintuitive consequence of relativity but it’s very much a real thing. While it seems paradoxical that both perspectives could each view the other’s clock ticking slower relative to their own, it’s actually not. It’s known as the Twin Paradox and there are a lot of resources which explain how it gets resolved. It basically boils down to whichever perspective is the one undergoing a change in its speed or direction will always be the perspective which ends up younger than the other. As long as the motion remains in a uniform direction at a uniform speed both perspectives will see the other aging slower relative to themselves.
What if they then meet?
Meeting would necessarily require acceleration - which is any change in speed (up or down) or change in direction.
One frame would have to hit the brakes, or the other the gas, in order for their motion to come to rest with respect to another. During that period of acceleration the accelerating frame will observe the others clock ticking faster, not slower, while the “stationary” frame would observe the others clock still continuing to tick slower. Basically, they always agree on who is accelerating and thus they always agree whose clock is ticking faster and whose is ticking slower.
"Somewhere in the universe" including right in front of you, from a random electron's perspective.
You sometimes hear that the light from this galaxy or whatever, has been underway for billion of years (distance: x lightyears). Does that make sense then? Suppose that this galaxy is speeding away.
And suppose you observe some supernova that lasts for a week. Could that by the same reasoning have taken years to happen on location?
Distance is just as relative as time. There is no such thing as a “true” amount of distance which separates the galaxy from Earth and consequently there is no “true” amount of time for which it takes that light to reach Earth. Just like different perspectives can’t agree on how much time fills a second, they also can’t agree on how much space fills an inch, or a meter, or a mile. Different perspectives will have different measurements of how far the galaxy is from Earth and consequently how long it took light to reach us.
If you were observing the galaxy speeding away than you would observe it’s clock ticking slower relative to your own, so it would be the opposite - a supernova which takes a week in the frame of reference of the galaxy could take a few years in your frame of reference.
Earth time isn’t a definitive reference, but I get OP’s question. The aging process and cell replication/death happen at a biologic rate, they have no concept of “time”. Will one appear aged equally despite time dilation?
The biological processes all obey the laws of physics. A ball has no concept of time either. If it takes 1 second for a ball to hit the floor from the table in my reference frame and 10 seconds in some other reference frame, a cell must also age accordingly
A second is a second according to the cells in your body. They’re going to age exactly the same as they always have.
Just because a different perspective counts a different number of seconds that passed for your cells to replicate and die doesn’t change the number of seconds that passed according to your cells to do those some things.
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Aren't you both saying the same thing?
Yes, rare instance has misunderstood.
Yeah, sorry I misunderstood him.
That’s what I said?
Sorry, I misunderstood!
Except that's wrong. What makes him younger than his son is the periods of acceleration he undergoes (speeding up, slowing down, speeding up the other way, slowing down again), which his son doesn't. Acceleration, like gravity, slows time; the two are equivalent. That's General Relativity.
Plus he was never "travelling at the speed of light" (or close to it) - that's just how it looked to his son. But to him it looked like his son was travelling close to the speed of light, too, and ageing slower. That's Special Relativity. And it drops out of the picture when one of them starts accelerating.
While they occur at a biological rate, that rate is still governed by the passage of time within that frame of reference.
If a person experiences 1 year of time passing in their frame of reference, it doesn’t matter how much time passed in another frame, their biological rates all experienced 1 year of time.
Biology absolutely has a concept of time. Time exist for everything.
my toxic trait: Is this a challenge?
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It's around 99.5% the speed of light. Nothing we can come anywhere near with current technology. The closer you get to the speed of light the more energy it takes to continue accelerating at the same rate even in a vacuum without factors like air resistance to overcome. Relativistic speeds are weird.