Does the future already exist? (Andromeda Paradox)
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- čas přidán 21. 05. 2024
- A special relativity paradox at 3 miles/hour!
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This video focusses on the Andromeda Paradox. This paradox is caused due to the relativity of simultaneity. A consequence of Einstein's special theory of relativity.
I discovered your channel two days ago, and you have become my favorite science communicator by far! Keep up the great work!
Great to hear that :) Welcome aboard :)
Exactly what happened to me. Great channel!
Sir Thoda Hindi mein bhi bola Karo kabhi kabhi samajh nahi aata hai@@Mahesh_Shenoy
Same
Ditto. This channel is soooo intuitive, and profound. Every. Single. Episode.
Physicist Carlo Rovelli has a nice short book called "Order of Time" where he explains this quite vividly. Basically "now" is only applicable to "here" and we intuitively extend it to things around, and that kind of works while discrepancies remain too small to notice. But on a larger scale "now" doesn't mean what we're used to, it loses its meaning. All the region of spacetime outside our past and future light cones is "extended present" with no fixed order "before or after or now" relative to us, and it's not directly observable anyway. He offers some casual metaphors from real life to get accustomed to such thinking.
Thanks for the recommendation :)
@@Mahesh_Shenoy How do you know that we don't see Andromeda galaxy as it is right now? Relativity of simultaneity means you cannot agree on what is right now outside your reference frame therefore you cannot claim that light takes time to travel towards you because that is only under the assumption that light travel at speed of light in every direction. The truth is two way speed of light is constant but the light could travel one way at any speed between c/2 and infinity.
@@classicalmechanic8914that's why Einstein already mentioned in his original 1905 paper about light Speed. He said that "all the theory is made under the speculation about TWO WAY LIGHT SPEED is 'c'. We never know one way light speed. So one way light speed can be even infinite, but there is no way to test it. So we kind of belive it that it is c/2. Because we can't even test it or prove it nor disprove it.
And nobody knows what the spacelike 'extended present' outside of our light cone means. It is interesting, as this is where inflation and all cosmic theories come in, considering the cosmic background radiation is within our (past) light cone. We have no idea or even an inklinkg what this spacelike extended present could even mean.
Now that I mention this, I wonder what the implications for black holes are, where apparently time and space kind of switch, this means there is a phase transition in what it means to be an spacelike extended present. Wonder what it could tell us about it, the black hole dynamics. Considering our current universe would be the spacelike extended present for the black hole at the event horizon where time and space switch roles and flip!
@@classicalmechanic8914It should be possible to see Andromeda (thougj may not be probable) at it is in the present or by a margin of a few seconds (also taking into account delay in our consciousness of reality). That is, thru a wormhole. But if there are naturally more wormholes in the universe, well, we could have been seeing things that are much farther away than they really are, and we are there seeing a mixed of observation of the past in the present.
That was the smoothest segue of introducing a sponsor into a CZcams video that I have ever seen.
Einstein was asked if a femtosecond is the shortest measurement of time. He answered no. The shortest measurement of time is the time between when a traffic light in New York City turns green and when the driver of the car behind you beeps his horn.
I hate it, but I respect it.
Mahesh, all the hard work in the animations and the smooth delivery of explanations are revolutionary and all, but deep down you know you've turned pro when you've seamlessly segue into the sponsor spot without any transition. Achievement unlocked!
Einstein says he is proud. It's ok if you didn't hear it, he was in another frame 😉
It's ok, he will hear about it in about 1 or 2 million years.
The clocks at the start not having a 9 is hurting my soul
And they have no zero either, so they are already one second in the future before they start.
Omg! I was sleep deprived. 😅
Imagine if you will going to Mars for three Earth years and when you get back to Earth you are three years older. Both Earth and Mars moved from day 1 to day 2 at the exact same moment in space. That would be forward motion, not time. Day 1 day 2 day 3 into Tomorrow, the future.
Ok. dude turned a commercial for website building into an existential crisis.
Ikr.... very cool
😂
It is all a lie. Time is not relevant to anything other than Earth.
This is the first video that's convinced me that faster-than-light travel is impossible, as it would create causal paradoxes:
Lets say we have three FTL communicators, two nearby (B & C), and one in Andromeda (A). Lets say B and C are nearby, but C is jogging. B says to A "tell C to tell me to say 42", then A tells C that, but C will hear that message days before B sent it, so can tell B not to send any message at all, creating a paradox.
It's only a paradox if you assume free will 😊
That’s not how it works, C will hear the message days before they would be able to observe B sending it but C’s observation of B sending it is irrelevant to affecting wether or not B did send it
I swear these misunderstandings are only possible because we’re taught a very self centred version of time. Going faster than the speed of light is not time travel otherwise we already have that with sound you can just go further away faster than the speed of sound and hear what happened earlier than your previous observation but if you were going slower than the speed of light you won’t be seeing before your previous observation.
Only difference in your example is now light is the one coming in second place.
Edit: I said the same thing twice
I never understood why people believe that faster than light is impossible because otherwise you could get a message before you observe someone sending it... Or that you could meet an alien before you saw them leave their home planet or whatever else.
Like none of that means FTL is impossible and isnt at all odd to think about even, nor is it timetravel.
Just because you travel say 2c doesnt mean you can affect the past by sending a message somewhere and them being able to send a response before you sent your message. Theyd only be able to send a response before they observed you sending a message, but your message was already sent and received. All this would mean is that you could receive a response at the same time as they observed you sending your original message through light but it wouldnt break anything. Thinking it would break anything is like thinking the fact that you can see someone yell something at a long distance before you can hear them is time travel or breaks the rules of nature.
Obviously FTL could well still be impossible no matter how advanced we get, but assuming that its impossible because you could receive information before you observed it being sent is ridiculous. It doesnt break any laws to be able to speak and interact with someone infront of you at the same time as you observe them approaching you from far away, because that person approaching from far away isnt a person, its just photons they gave off arriving after they arrived. If youre going to assume its impossible at least assume it for a sensible reason such as believing we wont ever find a method to go faster than light because it takes too much energy to accelerate mass that much, rather than falsely thinking its some kind of paradox.
@@Borg-mb8qv It's a paradox whether you assume free will or not. The entities at ABC could all be simple transistor circuits, and it would still result in a causal paradox.
If FTL is possible, then it would mean that c is not the speed of light but the speed of whatever travels FTL. We just update that and relativity stays put 😅
The Andromeda Paradox exemplifies that all of physics happens along time-like curves.
Andromeda is not just separated from us in space but also equally in time. Just as we can not reach Andromeda in space, we can not reach it in time. We're essentially de-synced in time by 2.5 million years. If we were to travel to Andromeda, that desync in time would shrink as the distance between us shrank. So when we arrive somewhere we don't just arrive there in space, but also in time. Hence the term, spacetime. With that in mind, the "present" is only local to you, and the further something is from you the more in the past it is from you as well.
This is why it's good to play with simulators that use a speed of light much slower than normal, so one can develop a better feel for how "now" is relative.
Speed has nothing to do with forward motion. You can go forward at 1 mph. Everything inside of you is only going 1 mph. Nothing inside of you will go faster or slower than you are.
It is astounding how you've managed to clear up EVERY single follow up question i had after watching your earlier videos (coming in from the triplet paradox video).
In three videos you have cleared up questions I've had unanswered for years.
You should be required viewing in every science class in every school, anywhere. This is a level of teaching excellence that I've not only never seen before, but never even thought possible.
If the universe is moving forward and you move forward with the universe, did you really move forward yourself? If I were on Mars at 9 o:clock what time would it be here on Earth? It wouldn't relate. The orbit of Mars is not equal to the orbit of Earth so the hours in the day would not even be close. If 1 day of Earth was 3 months of Mars how much older would I be when I get to mars and do I age the same as if I were on Earth? I would age the exact same on either planet of Galaxy. We are moving forward with the universe.
6:36 If you are wondering, even a very small speed like 1 meter per second (2.24mph), the time difference would be 3 days if my calculations are correct
Woah hold your horses, the future *does* have a meaning in relativity. It's a mirror of the past: everything that can affect us is in our past, everything we can affect is in our future. It is just that these terms are smaller than in our intuition: at a distance, the past does not touch the future, instead there is a huge timeframe of causally disconnected events where you can't agree whether they are in the past, present or future based on your reference frame (we might as well call all of that "quasipresent" or just "present" if we want, baring in mind it is not a moment in time but a huge region in spacetime).
Sir, Please keep sending us more of your Photons and Phonons recorded from non existing now to the Future
Ah ys
You always ask and answer the questions I have after watching other videos. Love it! Keep up the good work.
This is most special channel about special relativity!
Never had i seen such a natural integration of an ad . Very nice job Mahesh!
Once again our brother is back with his conversations with Einstein.
What a great video! Loved it! When I first learnt relativity I was very puzzled by the Lorentz transformation for time, t'=gamma(t-vx/c^2). It seemed odd that it contained x. Apparently it implied the change in time depends not only on relative speed but also how far away you are. You can get a big change in time by either having a high speed or a big spatial separation. It literally took me years to realize "so what". If only I'd seen your video back in the day! There is a relativity joke in there somewhere but I can't quite grasp it :D. I wonder if I could persuade you to do a video on spacelike intervals where for some observers the effect comes before the cause?
"The distinction between the past, present and future is only a stubbornly persistent illusion" -- Albert Einstein, 1922.
You are like a big brother to me, who simplify the core and hard concepts for me in the easiest way possible
Take love
Oh, I love this. And the topic of the future is really timely.
I have been studying the remaining portions of the writings of the pre-socratic philosopher Parmenides of Elea. Really odd stuff. He was of the belief that time was an illusion and that all past, present, and future exist simultaniously. His student was Zeno famous for Zeno's Paradoxes. It has gotten me very interested in the philisophical idea of Eternalism.
The fact that even at non-relativistic speeds, different reference frames have different ordering of distant events seems to support this position. But because what is happening distantly can't actually be measured and its information sent to us any faster than light anyway, it ends up leaving the world of science and entering the world of philosophy.
Thank you for this video. So good.
Ur literally my favourite youtuber, ur vids r the most interesting to me in yt than any other, Tq Mahesh sir for making these amazing cool explainer videos. And I'm v happy to see this channel growing in good pace, congrats for 100k subs, but i feel it's still underrated, u deserve a lot more than this and i think ull achieve that soon.
I don't know why, but my favorite aspect of these videos is the Socratic setup between him and Einstein. I love when Einstein goes: "BUT MAHESH!"
Wow. The way you integrated Squarespace was amazing!
Smooth af
8:46 this gave me goosebumps
I see this at 8:47 means I'm more fatigued at this moment 🥴
Fantastic explanation of the Andromeda Paradox! Apropos, the way you advertised squarespace was also great. I guess this was the first time I watched an advertisement until the end 😄.
To address the very last question in the video
You explain it very well and ill put it in different words:
Someone once explained it to me in a very simple way - each observer: me, the jogger and the aliens in Andromeda have their own time. Imagine it like a track, and the word "now" is a point on that track. Since every one has their own track, the word "now" is personal. Ie each person's now will refer to a point along his own tracks - there is no necessity to be able to map each point on your tracks to some point on another's (arbitrary) tracks. They are simply just different tracks, and each observer has chosen a different path through spacetime. You dont have to be able to link these tracks together, why would you?
This one of the greatest physics channels of all time and all reference frames ❤ . Btw mahesh you need to do some videos about quantum mechanics especially the string theory pls 🙏🙏🙏🙏🙏
Great!
Please do a video on gravitational time dilation as well and also videos on general relativity.
Yup, I have a few more to cover in special relativity, then I ll move to general relativity:)
I was jogging last week and totally knew that smooth squarespace segue was/is/will coming up.
Love your uploads, you were born to do this 😊
However, this means that any long-distance teleportation becomes an ideal time machine. As is FTL communication or FTL drive.
But then the question arises that how can we make teleportation possible even in the first place
4head thread
This is a great video on the "relativity of simultaneity." I think a deeper issue really is what is sometimes called the "conventionality of simultaneity," which asks, how do you even define simultaneity to begin with? And yes it is related to the one-way speed of light dilemma as well.
I think understanding "conventionality of simultaneity" is helpful to understanding "relativity of simultaneity."
Subscribed. Incredible way of thinking about so many ideas. 👍👍
My mind hadn't been this blown by physics since learning what neutron stars were a few years ago, and I'd been missing the feeling. Thanks for bringing me back into it.
Sir please make videos in physics in khan academy too why do you stop making videos btw I love your teaching skills sir 🥰
Wow great presentation Mahesh sir 👍🙏, actually "today is tomorrow's yesterday" 😅😅 similarly "present is future's past" and hence as per vedanta everything is relative and predetermined.
This guy is making physics way simpler for me
This channel is amazing. You good sir, do an amazing job explaining to people who are not experts. Also love the vibes od the channel, super upbeat and keeps it entertaining.
Since I was a little boy, it always made sense to me that free will is an illusion, that the nature of the Universe is deterministic. I stand by it to this day. We are nothing more than just a bunch of particles interacting with each other and all the others around us, no matter how sophisticatedly arranged, we (a bunch of particles) still have to exist and behave by the rules. Things evolve in time with an order, the math and all the unmeasurable amount of variables are just infinitely complicated for our small brains to understand them, much less predict them.
Nonetheless, the illusion feels real to us and we should enjoy it and just live our daily lives not caring about it, because in the end it doesn't really matter. Be happy and just enjoy this fascinating, unforgiving and beautiful Universe.
Why can "we( a bunch of particles)" choose to walk up a hill, while all the particles by themselves would follow their world line and universal law of motion and roll down it? Don't we all behave by the same physical rules? Why the contradiction?
Just discovered your channel and am binging all your videos. You're amazing. I love you! Your enthusiasm is infectious. And when you stop and are like "wait einstein what about this" your questions are exactly the questions that I have as you're talking, your flow is so perfect for me.
thanks for messing with my head again
got something new to think about for the next week
great vid!!
You are one of the best educators on Relativity out there today.
Best job of working your sponsor into the content I've ever seen.
The real paradox is how they were talking about all these when Aliens had to invade Earth million years ago
Happy to see you back sir.
Expecting you to appear on screen frequently instead of from time to time.
Depends on your relative motion to Mahesh.
What a superb channel!! Such a wonderful and engaging way of explaining these concepts. I love it ♥
I understood relatively perfectly for the first time. Thank you
this is the first time I hear about this paradox by name. This is also the first time I see someone trying to explain the idea of "but something must be happening NOW somewhere else!". It is a very hard concept to grasp since on earth we all basically share the same "now". Mindblowned.
Awesome video, thanks. You’re a great communicator
Thanks :)
Fantastic explanation. New favorite physics channel.
I am feeling proud that there are still some teachers in India who rather than just following very bad and wrong education style and system, changing the way to look at physics with another perspective and explaining real majic of universe with physics. One is you amd other one is Vigyan Recharge
This was really fun. And I love your energy!
I was thinking about this a few days ago while driving thanks for posting this video
@FloatHeadPhysics
So "in VERY short": Causality travels at the speed of light, hence talking about "now" (aka simultaneity between events) regarding something that is not absolutely sharing our point in space(time) is purely hypothetical... Because it will remain unknown until the light from the events reach us...
That's at least how it appears to me "now" ;)...
And thanks for another fantastically entertaining AND thought provoking AND informative video... That is quite the feat, and very much of it is due to Your personal presentation, Your apparent enthusiasm and engagement really "sells it" imho
((Of course I understand and appreciate that there is a LOT of hard work in making good approachable and easily understandable explanations to make that even possible)).
And I hope You manage to keep it up, and get the well deserved recognition and success that You deserve.
Best regards.
Hi Mahesh. I loved the video, thank you. But I have a question. At around 13:30 you point out that the jogger will claim that the light has been travelling for more than 1 second. But haven't you overlooked that the two clocks will be less than 1 light second apart (to her) because she is running? Or is this effect perhaps less significant?
Good catch 🙆
The distance would be length contracted. But, it still works out to be more than 1 second!
@@Mahesh_Shenoy Thanks!
Except the Lorentz factor at low speed is g = 1 + v^2/2, while clock bias goes as x*v, so you can always pick v and X so g doesn’t matter to first order.
@@DrDeuteron Yes, I came to a similar conclusion once I took a little more time to think about it.
Watching your videos always allow me to discover something amazing about our world. We are fortunate to have amazing researchers like you to provide us with these hard to grasp knowledges. Thank you
"Right Einstein!? WHAT IS GOING ON!!!?!?!?!?" is relatable as hell
Please make some videos on other topics also
This was a great video! Do you take the perspective of 'past light cone presentism' in this view? It seems to me, and it makes sense to me! Thanks to your previous video, I did research on the RPP argument (Andromeda argument) and i found a nice review paper on it, called On the Rietdijk Putnam Maxwell argument. It says there is horizontal spacelike presentism (which is what people generally think about when 'something is happening at Andromeda NOW'), bowtie presentism and as you now explain past light cone presentism. This stuff is truly fascinating, as indeed you are right all we can say is that Andromeda's present is in the spacelike area of OUR light cone.
I do think we can still get meaning out of an absolute present and absolute simultaneity in General Relativity though, please I would like to hear your thoughts on this. Flat spacetime, without gravitational time dilation in it, should necessarily have the same proper time propagation, and thus be absolutely simultaneous am I right? Love to hear your thoughts on this, whether in GR flat empty spacetime is necessarily simultaneous when seen from the definitions of a proper time perspective.
pretty great video man but i have a request umm can you plz let us use the ppt you are making for the video? that would be great
I'm watching and at 5:33 I understood where we're going. I love these aha-moments. Great video!
So I’ve heard of the double slit experiment and the double slit time experiment. But what about the double moving slit relative time experiment or double moving slit experiment were we have two things that can be observed if they are affected by light or not and one moves and is hit by the light then the other stays still and is hit by the light at a different time. Can we duplicate photon energy?
Brilliant video. Nice explanation of the “paradox”.
mahesh I have a doubt .please clarify .IN the video moving charges magnetic fields ,you said electrons length increases in conductor .I don't understand that .In proton perspective ,proton is stationery and electrons are moving .Then length should decrease for electrons .In electrons perspective electron is static and protons length decreases in conducter. This I understood
I can't understand the part with 3rd clock at 05:30. Where we should place those clocks? Shouldn't we put first and second clocks two times further from signal source to get delay doubled?
you can put clock anywhere. but you have to put a new signal source equidistant between the two clocks being synced
I love your content! It puts my 🧠 to work.
Oh dude, neuroengineer here, and it turns out that our idea of "now" might be happening all in our heads. Sure, our brains evolved in response to the non-relativistic environment that we've lived in for ages and ages and ages, but that might mean it's actually impossible for us to conceive of a world WITHOUT a "now". We're so intimately tied to our perspective from this little planet we might never be able to make intuitive sense of how time "really" works.
13:13 i am not convinced to this , because as soon as the clock reached at the same place as rest observer clock was then if light signal coming out from the clock will need to be travel 1 light sec distance(as speed of light for both observer must be same meaning we can't add any frame's speed to the speed of light so she can't say that the signal receiving by her is travelled more than speed of light as all other things are moving backward with respect to her ) so both observer sees the same time ticking. Kindly correct me if wrong or convince me by other examples.
Love the way you tied in determination and the promo for squarespace...
This is why I drive my car so carefully, what I see with other vehicle's position and velocities all takes place in a moving frame, me being at rest, so it's obvious that nothing is where I perceive it. It still is amazing how little power is required by the engine to accelerate the entire Universe. At least if I'm running late, moving the Universe just a little faster means I'm traveling backwards in time.
fyi that's classical relativity, not Einsteinian relativity, you're experiencing, and that (flawed but roughly accurate) model doesn't have any paradoxes of simultaneity -- still pretty cool you have a Universal Accelerator Pedal though! :)
I love the way you speak.
It's halfway to singing.
The Welsh are the same.
Im trying to figure if this time discrepancy is based on the joggers' instantaneous velocity, or would that need to be over the whole duration of the light's transit? For example, if the person on the bench suddenly got up and ran with the jogger, would he just see several andromeda days in fast forward over the few seconds of his acceleration?
No. He'd see the same light arriving at the same speed that light always arrives at. C. But...he would, due to his motion towards Andromeda, surmise that what was happening "NOW" in Andromeda (which he cannot actually see for another 2.5 million years) is a moment further in the future from the perspective of a stationary observer (the aliens) residing in Andromeda. Thinking about this can make you dizzy. 😂 Read the book "The Fabric of the Cosmos" by Brian Greene. Chapter 5: "The Frozen River" gives another excellent example of this 'paradox' but from the perspective of the aliens. If they move towards Earth, their "now" is in our future. If they move away from us, their "now" is in our past. In 2.5 million years, a 3rd party observer who viewed the events that occurred on Earth and in Andromeda from 2.5 million years in the past would say that when the aliens moved towards Earth, their "now" aligned with our future, and when the aliens moved away from Earth, their now aligned with our past. Which means that all of spacetime - past, present, and future - seemingly exist simultaneously. Which is why Brian Greene calls it "The Frozen River". A spacetime of past, present, and future that all exist simultaneously, leaving unresolved and up for debate the question as to why we perceive time as "flowing" when there's no solid evidence that time actually exists at all, except as a human consciousness means of measuring causality. And from there, it all starts to fall apart...
Tough to completly understand, but was still fun the parts o got. I wonder if it would be worthwhile getting into the perspective of the aliens on their frames of refrence.
Hi, Just thiught of this as i ran towards a star i saw whilst on the terrace - as i was running towards it, i see days into its future (relative ) and then when i suddenly Stop i see it a couple of days past. So do go from seing its future and as i slowdown to a stop i am seeing days rewind and seeing a few days old star ?
Sorry if the above doesn't make sense, wrote it in a hurry
that is not how it works. If you run towards it, you dont see days into the future. What you see will be the same as what someone standing beside you will see
absolutely loving this content! thank you
This is just so damn awesome, I"m going to write an article about this for my physics page inspired by your awesome explanation.
You are brilliant lector !
I recently read a book about an event which took place in the 1700s. A ship wrecked and a group of people survived, and eventually made it back to England, where they were from. In the time between the wreck, and the eventual return of some of the people, the people had been declared dead, the families had moved on, etc. Once new information came to light, it complicated things. It makes me think, before we had near instantaneous communication through telegraph, or eventually radio and light waves here on Earth, there wasn't even always an agreed upon, "NOW." In the same, "NOW," those people were declared dead in one part of the world, they were still struggling to survive in another.
The new quality of the videos is awesome
I love your t-shirts man 😭❤
Hmm, can it lead to replay? Does that mean that for sufficiently distant cellestial object with random variable emissions intensity, we can observe same pattern repeating at either dusk and dawn because at the start of the night we are having additional speed boost towards it and at the end of the night we have the opposite? If that effect was real, could we use it for getting better SNR in radio astronomy?
I have a question for you Mahesh: In the case of celestial events that happen over short times (such as this year's expected appearance of the T Corona Borealis going nova), I wonder if we could leverage the Andromeda Paradox in this way: Set up a series of telescopes on circular tracks, so that there's at least one telescope traveling quickly in any given direction at any given time. Since at least one would be moving quickly in the direction of an event (seeing "ahead" multiple days), it can relay this information to stationary telescopes to prepare to measure the event. The moving telescopes would be garbage for sensitive data, but they could help us prepare to make good observations, by telling us about the more obvious events before they occur. Do you think this is possible?
EDIT: I worked it out. T Corona Borealis is 2.8k light years away. A telescope moving at 5m/s would only grant ~24.5 min of advanced viewing. This might be a better job for satellites in orbit. A satellite traveling directly towards the event at 28.8km/h would catch it about 24h in advance. The advanced warning would increase with distance to the event.
Heyoh, I was listening to your voice earlier on another channel. You were teaching me about ferromagnetism, and jumped past the exchange interaction. That eternal child in me is still shouting "but why?" I'm listening to lectures on it right now, but they are slow and dry. Can I request a bit of your pizzazz applied to explaining these concepts a bit deeper?
Thanks!
The idea that “now” far away has no meaning is partly why I get twitchy when people say the observable universe is something like 90 billion light years across, instead of around 27 billion.
Must be doing well in the algorithm I've never been recommended this channel
This complements Sabine Hossenfelder's top video of all time (no pun intended) titled Does The Past Still Exist? I'd be interested to hear your thoughts on the Block Universe. It seems most physicists think it exists, while others don't believe in it at all but don't really come up with good explanations for why they think so other than it conflicts with their own experiences, which is not a good metric for what really exists.
Loved this one
Awesome videos man. No flux given!
Sir I have a confusion sir if now is not 'now' then time traveling is what you are traveling to the past???
Love your videos and please make the paradox of quantum mechanics ❤❤❤❤❤❤
Why the time to see (moving) clocks is not taken into consideration ?
The clocks are moving towards the jogger then the reflected light from right clock will take longer to reach the jogger than the clock on the left which started late so the differences would add up. So shouldn't the jogger observe the clocks start at same time ?
Bravo, bravo, bravo, to you! You made this so easy to understand. Thank you!
Not _exactly_ on topic, but legendary comedian Steven Wright, on a recent Late Show appearance, quoted a line from his new book: "The present is a past factory."
Finally someone is talking about this simple example to explain the illusion of past/present/future. It's happening in front of our eyes but hardly anyone use this as an example.
There can't be a better example than night sky. It's so simple yet so fascinating. Thank You.
The apparent paradox is not due to the physics but psychology. We assume that time flows at the same rate everywhere, so there is a universal "now", but it's not the case. It's similar to the way people think mirrors reverse images left-to-right because we're used to rotating on a vertical axis. Mirrors actually reverse images front-to-back.
And because we imagine ourselves looking out from the reflection's POV due to being wired for human empathy and to see faces in other things (understandable since it otherwise looks exactly like our face). So we see the hand on the right as the reflection's left hand, even though we can plainly see that the hand is still on our right so isn't flipped.
How fast can you change your frame? Can you just change it immediately, like you see something and you start walking and now days have passed in that location
Or do you have to be moving for millions of years?
Every change in your velocity, even by 1 mm/s, is considered a change of frame, and is subject to all these transformations. How fast you can change is a question of how much acceleration you can perform & endure.
Ok I see, it happens immediately
it can be immediate. as soon as you have a different speed, you are in a different frame.
"I think that's the biggest takeaway from special relativity that the idea of now far away, really, has no meaning. I'll see you"....best mic drop moment ever!!
Could this effect be used by an advanced civilization for stuff like catching supernovae? One telescope jogging with a view of all of Andromeda, and another with a different acceleration with a very high resolution to focus on the nova as it happens?
Hmm. How do time dilation and length contraction work here?
The jogger says the clock is more than 1 ls away... but it's also length contracted so it would be closer? And time dilated so it would tick slower and not read more than 5s?
Or is all that what combines to make the picture still 4s?
I feel like what I need is one of these thought experiments that considers all of the effects, in all reference frames through the entire experiment, before and after the interaction.
the picture would still be 4s
Time dilation and length contraction will be in this case but it will be vvvvvvvv less, bcs the speed of the jogger is vvvvvv less
That's what I was wondering too. Even though the relativistic changes would be small, compounded over the vast distance, the result might make everything once again appear synchronized.