To clarify: In order for two observers to measure the passage of time and confidently compare those measurements, they must share _two_ events (the starting of the clocks _and_ the stopping of the clocks). Without having both events in common, the comparison between the clocks is meaningless. On the space station, I'm traveling along the spacetime path that _maximizes_ the time between those events. All other paths, including Rocket Clone's, _must_ be shorter.

@chonchjohnch

5 жыл бұрын

The Science Asylum what’s the general equivalent of the “clock” here?

@ScienceAsylum

5 жыл бұрын

@@chonchjohnch A "clock" is any device that measures time between two events. It doesn't really matter what it is, but you can imagine a fancy stopwatch (if that helps).

@corwin-7365

5 жыл бұрын

Indeed, anything that evolves over time counts as a "clock". It could be a burning candle, a chemical reaction, or a person counting "One one thousand, two one thousand, three one thousand...".

@SidKnight

4 жыл бұрын

Soooooooo... is it fair to say that time passage is relative to the speed of light?

@corwin-7365

4 жыл бұрын

*Sid Knight* said: _is it fair to say that time passage is relative to the speed of light?_ I'd say so. Everything at our macro level that presents the passage of time either involves the interaction of fields at light speed or the movement of sub-light speed particles which are subject to SR effects because they move through a space that is subject to light speed. And at the micro level this still seems to hold true, even for a point particle like the muon whose lifetime becomes extended when it is moving through space. So, yes, I imagine that if you could find a piece of space where the speed of light was different then the flow of time there should be different by the same amount. There is an old saying that _time is what stops everything from happening at once._ I guess we could modify that to say that it's the speed of light in a vacuum, combined with a space through which things must travel, that stops everything from happening at once! :-)

Best quote ever: “The universe doesnt have a problem, we do”

@pbp6741

6 жыл бұрын

... but I am a part of the universe.

@Trident_Euclid

6 жыл бұрын

PB P Still. it's only your problem.

@josephobioma8558

6 жыл бұрын

The universe described by the equations below has no problem... c = speed of light Distance of earth to star (as measured from earth or star) = 8 light years te = gamma [ tr - xr(v/c^2) ] tr = gamma [ te - xe(v/c^2) ] xr = gamma [ -v*te + xe ] xe = gamma [ -v*tr + xr ] te = t_earth (passage of earth time for the round trip as measured on earth or earth time as predicted from rocket) tr = t_rocket (passage of rocket time for the round trip as measured on rocket or rocket time as predicted from earth) xe = x_earth (distance of round trip as measured from earth or earth distance predicted from rocket) xr = x_rocket (distance of round trip as measured from rocket or rocket distance predicted from earth) beta = v/c = 0.55 gamma = 1/sqrt(1-beta^2) = 1.19737 Step 1: We are on earth and we measure/calculate te. Step 2: We are on earth and we predict tr. Step 3: We are on the rocket and we predict te. Step 4: We compare te from step 1 and te from step 3. Step 1: Time we measure on earth (with earth clock) xe = 2*8 light years = 16c v = 0.55c te = xe/v = 16/.55 = 29.09 te = 29.1 years Step 2: Rocket time we measure on rocket (with rocket clock) or rocket time we predict on earth (with relativity) tr = gamma [ te - xe(v/c^2) ] tr = 1.19737 [ 29.09 - 16c(0.55c/c^2) ] = 24.29 tr = 24.3 years Step 3: Earth time we predict on rocket (with relativity) Substitute xr = gamma [ -v*te + xe ] into te = gamma [ tr - xr(v/c^2) ] te [1 - (gamma*beta)^2] = gamma*tr - (xe/c)*(gamma/c)^2 te = [gamma*tr - (xe*v)*(gamma/c)^2 ] / [1 - (gamma*beta)^2] te = [gamma*tr - (16c*0.55c)*(gamma/c)^2 ] / [1 - (gamma*beta)^2] te = [29.091 - 12.217] / [1 - 0.434] = 29.1 te = 29.1 years Step 4: te from step 1 (earth time we measure on earth) = 29.1 years te from step 3 (earth time we predict from rocket) = 29.1 years

@zombywoof1072

6 жыл бұрын

Your face is wrinkled up with the effort to make people "get it." Just short of frustration, lol.

@theophilus749

5 жыл бұрын

Indeed! It's a problem of a (tiny) _part_ of the universe, then.

1 Dislike?! They probably tried to hit the "Like" button from someone else's coordinate system.

@sherbatt4769

6 жыл бұрын

Or a few likes quantum tunneled to the dislikes

@bytefu

6 жыл бұрын

These clicks were travelling through mood field and interacted with it by absorbing grumpy bosons, flipping their like charge.

@valerioboldreghini4239

6 жыл бұрын

You would make Albert happy!!

@stauroulapatsourou7278

6 жыл бұрын

Oh, hahaha!!😂

@thenasadude6878

6 жыл бұрын

Those are just likes that flipped their spin.

This channel doesn't just make videos, you touch every aspect of the problem which i haven't seen in other channels

@constpegasus

6 жыл бұрын

jai ho yes indeed.

@AlleyKatt

6 жыл бұрын

That's it! I was wondering what it was about this goofball that I enjoy his videos as I do.

@DoctorSyn11

5 жыл бұрын

The trouble with KZread is that the articles and comments aren’t vetted by a competent authority so a lot of them are cockeyed nonsense put up by idiots. Wikipedia is a better source of information.

@phenomenalphysics3548

5 жыл бұрын

exactly!!

I have watched Matt O'dowd explain this exact same thing, and I could never really understand it. After watching this video, I understand it completely. Thank you! You have an incredible ability to simplify complex ideas. Honesty the best physics channel on youtube.

@ScienceAsylum

2 жыл бұрын

Thanks! Glad it helped 🤓

Minutephysics didn't do justice to this paradox and I was searching for a better explanation.This one was much better.

@new-knowledge8040

6 жыл бұрын

I'm sticking with my 4D look at reality. By looking at the 4D view of reality, one sees that all objects move with the c magnitude of motion, and they all do so within that 4D environment known as Space-Time. The only change still possible is changing the direction of travel within Space-Time. 4D rotation also takes place while doing so. If you then create a simple geometric representation of this, you can use it to derive all of the Special Relativity mathematical equations, along with the Lorentz Transformation equations, and you can do so even if you have never seen these equations beforehand. This also eliminates any trouble resolving the Twin Paradox.

@admiralhyperspace0015

6 жыл бұрын

NEWKNOWLEDGE : Sir this one debunked the acceleration point of view that bothered me.I haven't solved lorentz equations as I am a high school student but I did create a better scenario for twin paradox and solved it using them and got a better understanding.This video made me do that. 4D spacetime is impossible to imagine for me.I stick with 3d version with colour differences but the concrete way is u pick up a pencil and do the necessary math...You will learn much more than from a video.

@new-knowledge8040

6 жыл бұрын

I made my own Special Relativity KZread videos. They are a step by step analysis of motion which then led me to the cause of the special relativity(SR) phenomena. The next step was to convert the understanding into a geometric representation. This then made it an easy breezy job to derive the SR mathematical equations, and resolve the twin paradox etc. So my method was to first figure out what is what, and thus understand what special relativity was all about, and then use that understanding to create the equations. Plus you only need to view one dimension of space of the 4D space-time to get the job done. But the main point of my videos is to show that by analyzing motion, just about anybody can discover special relativity on their own, and derive all of the SR mathematical equations on their own as well.

@admiralhyperspace0015

6 жыл бұрын

NEWKNOWLEDGE:That is obvious if you are a genius.

@admiralhyperspace0015

6 жыл бұрын

I shall watch ur videos some day.Thanks!!!

This channel is so underrated !!

@lxathu

6 жыл бұрын

Agree. It does not only touch interesting problems but it also has its own valuable characteristic like the famous French Once upon a Time... series.

@cinegraphics

3 жыл бұрын

Overrated. The explanation is wrong.

@Xayuap

2 жыл бұрын

u r övrratd

@betazep

2 жыл бұрын

I rate it as my favorite channel tho… hmmm. :)

This started as a confusing entangled mess and you weave it all out beautifully. It's amazing how your brain manages to deconstruct every part of the paradox, anticipate the viewers' objections and give them a satisfactory answer. I am a big fan of Fermi lab Dr Lincoln's use of equations to explain relativity. But you just beat everyone when it comes to manipulating the Space time diagrams!

Truly wonderful. In decades of being bothered about explanations of this, this is the only accessible one that makes sense. Thank you!

@ScienceAsylum

6 жыл бұрын

You're welcome :-)

I'll watch this again, because it's not yet 100% clear, but I think I've been finally put on the correct track. Thank you Nick for making relativity more "human" and less of "a mathematical abstraction we can experimentally check", so to speak.

this is the first time I feel I've ever properly understood this!! And boy have I read a number of explanations! PS your physics book is awesome :-)

@corwin-7365

5 жыл бұрын

He does a book?

Fermilab also coincidentally posted two videos on the Twins Paradox recently that also explained why acceleration is not the cause of the paradox. In the Fermilab video he considered a thought experiment where there are three observers: one on Earth, one on a ship flying past the Earth toward a star at high speed and another on a ship flying past the star at the same high speed toward the Earth. None of the observers experience any acceleration, they all have constant speeds relative to each other. As the outbound ship passes the Earth they start a timer. When the outbound ship and the inbound ship pass each other at the halfway point the outbound ship holds up a big sign showing the time the outbound ship claims has passed. The inbound ship starts its own timer and as it passes the Earth it holds up a sign showing the time the outbound ship experienced plus the time the inbound ship experienced since that event. As expected when you do the correct transformations the total of the two times from the ships is less than the total time the Earth observer experienced.

@surfinch

Жыл бұрын

Link please

@AdityaRaj-hp8tn

Жыл бұрын

@@surfinch just search fermilab twins paradox

@marscience7819

5 ай бұрын

This is the best way to resolve the paradox if one wants to avoid accelerations. However, the problem then becomes an "information transfer" issue, and not a matter of which twin actually ages differently. An asymmetry is introduced between the original two twins, as one transfers info from one particular set of clock/coordinates to another, distinct set of clocks/coordinates, and the other twin has no such transfer of information. Personally, I like the acceleration explanation much better than the non-acceleration one, because I understand better what an acceleration is compared to "transfer of information".

You really gave the explanation which I was looking for all these years!!!...Glad I watched this 😌

Does it matter whether you or Rocket Clone is the one actually moving/accelerating with respect to space/time? Rocket Clone could perceive you accelerating away and back toward you while he is stationary-but does it matter, in terms of relative clock-speed, which one is actually stationary?

@joepierson3859

2 жыл бұрын

It's not who is stationary but who is not accelerating.

@cjjones999

2 жыл бұрын

@@joepierson3859 accelerating with respect to what?

@joepierson3859

2 жыл бұрын

@@cjjones999 only velocity is relative and measured relative to something on the other hand acceleration is absolute and needs no reference

@quantisedspace7047

20 күн бұрын

​@@cjjones999Nothing. I was always led to believe that acceleration was absolute, only speed was relative.

I am always very impressed by how well you do your interaction with your clones.

unbelievable to see your channel grow this fast, been here before 1k but now it's already 70k. keep it up!

You are the first person I know who could ever clarify so brilliantly this age old "Paradox"! THANKS! Yes -- it is caused by doing a simplistic math of just the time -- ignoring the core reason -- longer space-time path! Remember, I was so frustrated after a third failed attempt of otherwise sensible professional that I almost pleaded you to jump into this subject and explain in your 100% articulate Style! I always like the explanation when you plug in numbers in those equations, and actually draw the consequences! It removes any confusion!

@ScienceAsylum

6 жыл бұрын

Glad you liked it! This video took a lot of planning.

@fakherhalim

6 жыл бұрын

Very intelligently explained! I really appreciate how you steadily kept on building the common misconception path (others routinely follow), and then pin pointing exactly what was wrong with that line of reasoning -- it made me really happy! I appreciate your efforts and want you to come up with videos with similar level of numerical/graphical clarity on other relativistic/quantum topics!

@Falkdr

5 жыл бұрын

With his explanation and knowing its a "mistake" with the transformation and not a paradox at all now makes the real (relative) scenario more comprehensible than the paradox. Lol :D

Thanks for your videos. They give a courage for young people to get into science.

Thank you! The common explanation of change of frame of reference was bothering me since we should still have a difference in time due to their relative difference in motion even if acceleration was not involved. Thank you for the synthesis of the rules.

This episode was much better on wrapping up the explanation. Kudos for you! Thanks for your wonderful work.

This video should be a standard in special relativity textbooks.I mean Wow.

@colman123456

5 жыл бұрын

how do you put a video in a textbook?

@jesusk1358

5 жыл бұрын

And also, he said the problem doesn't need acceleration which is incorrect.

@corwin-7365

5 жыл бұрын

True. But it was just a passing comment... and he then went on to explain how it really did matter. Which differs from the FermiLab video which fundamentally claims acceleration doesn't matter and is just wrong!

@sugarfree4073

4 жыл бұрын

@@corwin-7365 My take is that he was saying acceleration matters, but it isn't responsible for the paradox, it is just one relative term that you can ignore and still show that it isn't a paradox.

@corwin-7365

4 жыл бұрын

@@sugarfree4073 - he might be saying that... but I hope not, since the paradox (and resolution) completely arise from the nature of the acceleration.

Everybody gets a clock 😂

@corwin-7365

5 жыл бұрын

The true way to reconcile the 'paradox'! :-)

This channel is so underrated !! i love it please share it on social media

'Paradoxes are not a problem with the Universe, they're a problem of the human mind'. Thanks Nick. You've given me more to think about than just paradoxes.

Early enough to make a compliment. Been here since 5000 sub. Sooooo glad that you got so many subscribers. You even answered a question of mine in an older video. Thank you and keep up !!!

Well, I have an understanding problem: This transformation thing seems to work only, when one part is already considered as the "moving" one and the other one as "stationary", doesn't it? If Rule One is valid, then for Space Clone, it must seem, as if Earth Guy speeds up away and then flew back to Space Clone. This means, that in Space Clone's perception, he himself would be the stationary one, whose path is projected on the y-axis. According to this perception, Earth Guy would be the one, who is travelling through space. Consequently, now Earth Guy's path should have to be projected as the bulking out one space-x-axis-wise "to the right" in the diagram and then back to the stationary Space Clone. From the perspective of Space Clone, the grid-squeezing-thingy should then also have to be applied, with the consequence, that from his view, Earth Guy should be the space travelling one, whose time was slower. Earth Guy would have to be younger. In conclusion, the grid squeezing illustrates only, HOW the travelling part should be the younger one. But it seems for me as if it does not explain, which guy should be considered as the travelling part, when speed and acceleration of one of them is only measured relative to the other one.

@adammarkiewicz3375

3 жыл бұрын

So who is younger after rocketman returns? And why? I admit I'm lost here.

@frizzzyReloaded

3 жыл бұрын

Younger should be, whoever is considered as "moving", the paradox doesn't seem to be solved by this video: In the space-time-diagram, one of the twins is displayed stationary without moving through space, his graph in stays on the y-axis. The other one is displayed as moving through space. Because of the diagram shifting, the moving one has to be younger than stationary one. But since the motion is only relative, for both of them it seems like the other one would be the moving one. Consequently, for both of them the diagram would have to be drawn with the other one as the moving one. The result of the diagram shifting would then be that for both of them, the moving other one should be younger. Paradoxically. How can we decide, whose diagram is objectively right? Because ScienceGuy made that decision by drawing the Earth Person as stationary and Space Clone as moving. At least it seems like that for me, who has no deeper understanding of the matter.

@quantisedspace7047

20 күн бұрын

Yes, exactly this: the traveling part I've never had a problem with, but the whole paradox is that either of them could be considered moving, so A and B are both younger than each other. The paradox is 'which do we consider moving' and why.

@frizzzyReloaded

20 күн бұрын

​​@@quantisedspace7047 Absolutely. Well summarized. And now, three years later, I still didn't get a satisfactory answer. Although this video and many others try to give the impression to have an answer.

I think I need to watch this a few times for it to sink in... It is the "paradox" that does my head in too..

This is the best explanation of the twins paradox. Other explanations alludes to the same solutions and misconceptions but left me more confused. The last part about needing 2 shared events to make actual measurement rather than simply making a prediction was very insightful.

@ScienceAsylum

Жыл бұрын

Glad I could help! The two shared events is the main point of this video.

Thanks a lot!!! I've been asking this question for twenty years and this is the first time I am satisfied with the answer (even though I'll have to watch this video several times, pausing, drawing spacetime diagrams and doing some calculations in order to fully understand it, since I'm not very good at Physics). I'd just like to know what would happen if the universe was finite but borderless? (i.e. it is possible for someone to go back to the starting point always walking in the same direction). In this case, would a non-accelerating rocket twin still see an older resting twin when he came back to the starting point? (the rocket twin is always traveling in the same direction, without any acceleration)

@ScienceAsylum

5 жыл бұрын

Hmmm... Well, first, even if the universe was finite and borderless, the clone/twin would never be able to get back here that way because the universe is expanding too quickly. Buuuuuuuuut, assuming it wasn't expanding the fast? I'd need to think about it a while.

@corwin-7365

5 жыл бұрын

Wrap-around universes don't work nicely with Special Relativity (which doesn't mean they couldn't exist... just that physics would be more yukky). For example, a wrap-around universe (like on the old Asteroids game) has a defined width. But in SR observers at different velocities would see a different width! Basically, so long as you don't send messages all the way around the universe to behind you, the universe would look like Special Relativity. If you could send a message all the way around, you'd be able to detect how fast you were moving relative to an absolute space!

@aliriza1688

2 жыл бұрын

Excellent question, which I have been trying to figure out for a while. If we assume that this is a wrap around universe, and that the above rules for relativity still all hold true, then geometrically this would mean that as rocket twin's path goes off diagonally to the right, he wraps around the time axis cylindrically, as an extra dimension, and comes back and meets up with earth twin at some future point. Since the stationary paths always take maximum time, the earth twin must be older. Problem is, due to the rule about all observers are equal and can consider themselves stationary, this reasoning also applies to rocket twin, which appears paradoxical. Another problem is that the light signal of the initial event (rocket twin's departure) comes back and meets the stationary observer before the actual meeting, producing a hall of mirrors type situation. This is assuming that general relativity doesn't come into play, which it probably will, since we have warped the spacetime into a cylinder.

I like this video not because I now understand everything but because a lot of thing I thought I knew about it was wrong (oversimplified). In textbooks I jst assumed the twin that stayed on earth was in a prefered reference frame.

Christian Gingras Nice attempt to explain the paradox. Here is a simpler explanation: When the Sarah is flying away from Earth at 95% the speed of light, the radio communication is impaired because of a Doppler shift. Both sister need to tune their 1 GHz frequency to 50 MHz, which electrical engineers call carrier frequency. The AM or FM modulated signal, a slower wave which modify slightly the carrier frequency amplitude or frequency is equally slower. All embedded binary code are also streaming 20 times slower. The decoded voice of Sarah is deeper, like playing a vinyl disc or magnetic cassette in slow motion and the video are almost still pictures. A year later, Sarah turn around and come back toward Earth at 95% the speed of light, the following happen: That day, one year after their separation, Alice on Earth keep receiving the slow stream of radio at 50 MHz. She just received the video from Sarah telling how boring it is now, after 2 weeks of travel. She think her sister is crazy, talking about 2 weeks when in reality she his gone for a year and she is supposed to turn around now. Sarah also receive old news from her sister on Earth. She see the video telling her that she already miss her after two weeks of separation. However, the radio is fucked up because Sarah at the switch frequency from 50 MHz (for the 1 GHz carrier frequency) to 20 GHz. Also, the voice sound like chip monks and the videos are 20 times too fast. As the time pass between 12 month and 24 month of the total duration, the video that Sarah receive from Alice catch-up with the real time. Everything synchronize just right so that the last day of this 2 years voyage, Sarah can see a video of her sister recorded only 20 days earlier. For Alice, the second year events are a little more complicated to explain. She keep receiving outdated video on the radio station tuned at 50 MHz. Suddenly, 2 weeks before the end of the 2 years trip, the frequency jump from 50 MHz to 20 GHz. The video from Sarah describe that she now prepare to turn around. Alice think that she is crazy to announce that after 23.5 months. Then, during these last 2 weeks, Alice receive all the videos from Sarah describing that entire year where she is flying back to Earth. Finally, both sisters re-unite and they both aged by exactly 2 years. End of paradox.

@thedeemon

6 жыл бұрын

Wrong. What they'll see in received signals is described well, but you completely ignored time dilation that will make Sarah actually younger. You completely missed the relativity part.

@moiquiregardevideo

5 жыл бұрын

@@thedeemon The time dilation is carefully documented by the carier frequency of the radio communication. It occurs at different absolute time for both sisters. Note that for 2 weeks, there is a length extension while the rest of the 23 month and 2 weeks, there is length contraction.

@thedeemon

5 жыл бұрын

If in your scenario sisters re-unite aged exactly the same, it's a direct contradiction to what special relativity predicts and what many experiments show.

@moiquiregardevideo

5 жыл бұрын

@@thedeemon That is the point, Einstein pulled science from the dark age by proving the atom theory, calculating the size of water molecule from Brownian motion. He also made mistakes. He revised the equation for relativity years after years until nobody found further errors. Einstein never promoted the incoherent aging of the twin paradox. He probably knew it was wrong. His other work eclipse so much these detail, who knew people would still resurrect the worst of the work of a genius.

Much better then that first one! This video would have to be THE best one ever made, explaining the notion of "relative time" .While doing special relativity calculations, it is SO easy to get lost in the math to forget "whose time delta are we calculating and in whose reference frame?". This just nails that, Great. Except what about the "Twin's Paradox" which this video was supposed to explain? In Twin's paradox, the "rocket twin" IS supposed to come back to meet his stationary twin/clone again. So when they meet again, they both are at rest at the same place and time!! No ambiguity about frames of reference there. WHAT do they perceive at end, is the whole question!! Yes, Nick does come up with the nice thought experiment of "what if the travelling twin was already in motion at the point when the FIRST depart?" Great beginning!. Just complete that though experiment, and bring back the travelling twin back (that would have to involve acceleration, IMO, but at this point, i don't freaking care!!) Just SOMEHOW/anyhow bring him back, at rest with his stationary twin, and explain the timeline PLEASE!!

Hey, long time subscriber, and my classes get a lot from you too! I am preparing to teach special relativity and had a question - in the twins paradox, does the rocket twin come back shorter? High school books emphasise a real, notable difference in time (since the twin comes back younger), but only an apparent difference in length which is only observable under the conditions talked about in special relativity. So when the frames of reference once again come together for the two individuals, there is a permanent difference in time, but length remains unchanged - is this correct?

@ScienceAsylum

2 жыл бұрын

Great question! No, the astronaut doesn't come back shorter... but they _do_ come back having traveled a different _distance_ than the Earth observer thinks they did. The "permanent differences" are the ones that accumulated over the entire trip. The length of the astronaut is only a local instantaneous observation.

@chrisranson2619

2 жыл бұрын

@@ScienceAsylum Brilliant, thanks so much!

After all this time dwelling on this, I think I want to see the version of this accelerationless scenario where the two send wireless photos of themselves and their clocks to each other the whole trip. I know it'll get a lot more complicated, but I'm only on the very cusp of understanding this and why one's coordinate system ends up less tall than the other. I can't quite cross that finish line...

Amazing how you touch upon so many things in just 10 minutes. I took close to 17 hours of video to build up to this finale and therefore breaking every rule of becoming a popular KZreadr :-) But boy did I have fun while doing it.

Now confused on a much higher level. Thanks!

Nick, you have a wonderful talent when it comes to explaining complex concepts, a natural teacher.

Omg! You are a life saver! I have been searching around the internet to find an answer to this question that satisfies me and this is by far the most satisfying! Time to sit down, roll up the sleeves, and do some Lorentz transformations myself!

Fantastic. I always thought this was a change of simultaneity at the accelerations, and it is, but this explains the cause of that change beautifully.

A question Using the graph can you show how approaching a black hole will affect the relative time to each twin ?

That was an excellent explanation, much better this time. I'm glad you used space-time diagrams and you also did a great job showing the wiggle-room involved when the events we're trying to talk about are at different locations. -Matt

Sir, I am satisfied with this explanation. Seriously, your work truly is amazing. You take so much time and you put so much work into every of your videos... it's so amazing

Man I wish I could help you, get more subscribers and build your channel as fast as possible... having said that I am 100% confident you are going to make it big.... I'm talking millions of subscribers... you're totally unique and excellent at your brand of humour/education.. flawless... I really really hope people manage to find out about your channel, you deserve the success. I've only just subscribed but seen all of your videos at least twice over if not more... and you've shot to the top of my favorite science channel list straight away.. we're talking over the likes of Veritasium, PBS space time, Issac Arthur.... the big hitters... you're just better and I'm pretty sure it's because of the comedy element... but your content isn't bad either (I'm being modest) I've been watching KZread videos on GR and quantum mechanics for over 10 years.. and I've only just started to see GR in a more coherent light thanks to your videos.. keep it up my man and best of luck with the channel ;-) (Could easily see this show being on TV) oh one thing I wanted to ask... so your real name is Nick Lucid?

@ScienceAsylum

6 жыл бұрын

Thanks! I'm hoping my visit to VidCon U.S. this coming June is going to be my big break. I'm involved in some official stuff, so lots of "networking" opportunities and stuff.

You had me at "paradox isn't a problem with the universe it's a problem with our perception"

I understood better than the last explanation you did of this, but I'm still a little confused about why you need two shared events and what exactly a coordinate transformation IS. can you clarify?

@ScienceAsylum

6 жыл бұрын

Say we measured the time with some fancy stop watches. We need two shared events because we have to agree on when to start our stop watches _and_ when to stop them. We can't do that unless we're at the same place and the same time for each one of those events. A coordinate transformation lets you take measurements in one coordinate system and see what those same measurements look like in a different coordinate system. Simple example: You're sitting across a table from your friend facing them. You measure where the kitchen is relative to you. Now you want to know where the kitchen is relative to your friend. What do you do? You have to shift your measurement by the width of the table and rotate everything by 180 degrees (so that now you're looking through their eyes instead of yours).

@Lucky10279

6 жыл бұрын

The Science Asylum Ok, now I get what you mean by coordinate transformation. I was thinking it was something like converting between cartesian and polar coordinates in trigonometry. Keeping the same type of units but looking from a different perspective makes a lot more sense. Thanks!

@Lucky10279

6 жыл бұрын

The Science Asylum I think I get what you mean about agreeing when to start measuring and when to stop, but I still feel a little confused. Could you give another example? And thanks for the response. I appreciate how well thought your videos and how you take viewer comments into account. :)

@ScienceAsylum

6 жыл бұрын

So, you and your friend decide to measure how much time passes for yourselves after lunch (at the table from my earlier example). While you're sitting at the table, you can easily start and stop your watches at the same time. Instead, let's say you start your watches together just before you leave the table. No problem so far... but then you both leave and drive to your own homes. How do you know when to stop your watches and make sure you stop them _at the same time_ if you're in different places? You could call each other on the phone, but that signal takes a little bit of time to travel between your phones (maybe half of a second). It'll be close, but it won't be perfect.

Maaaaaaannnnnnn......... AT LAST!!! Finnally the twin paradox makes sense. Why can't everyone else explain the things like you do?! Thanks a lot (really)!!!

@TheScienceAsylum. As usual great videos. Thanks. One things is still not clear, in the final conclusive explanation where there are 2 shared events, in the second event are twin brothers of same age or different age? If they are of different age, does it mean our body biology also slows or fastens?

@ScienceAsylum

3 жыл бұрын

The twins are different ages when they arrive at that second event. It's a difference in the passage of _time itself._ Anything affected by that time, will be different too.

I am going to have to watch this again (again). I understand the premise at the start and the conclusion at the end but I think I zoned out in the middle. TBH, I think I might just have to take your word for it. You are quite right, for years I had been under the illusion that the twin paradox is solved because: acceleration. I will need to prime my consciousness with a couple more of your related videos if only to get my head into the correct reference frame. That and hit the pause button more often to let things sink in.

@ScienceAsylum

2 жыл бұрын

The difference is more fundamental than acceleration. Time dilation is all about measurements. To compare measurements of time, you need to have two events in common. There are many ways that spacetime paths can have two events in common, only one of which is acceleration. (To be fair, the way the paradox is traditionally stated and the way it's stated in this video, acceleration _is_ at play. My main point is just that it doesn't _have_ to be acceleration, so the paradox isn't actually _about_ the acceleration.)

@F16_viper_pilot

Жыл бұрын

Yeah, I’m in the same boat. The explanation travels closer to light speed than my brain, so I’m waiting for the two to cross paths again with each other and compare notes. 🙂

@MrCmon113

9 ай бұрын

@@ScienceAsylum Ok... Then what is a situation in which you would get two clocks showing different times without acceleration?

@MrCmon113

9 ай бұрын

@@F16_viper_pilot The fundamental thing that breaks the symmetry and that's responsible for actually disagreeing clocks (clocks in same place disagreeing after formerly having agreed) is acceleration. There is simply nothing else it could be.

Ive searched for videos all day on this problem and not one of them was able to answer the question in a way that couldnt function. This video however was the most helpful and i think i finally understand

@ScienceAsylum

4 жыл бұрын

Glad I could help :-)

3:50 No, accelerated points of view do not require general relativity. They do require some of the math typically associated with general relativity (specifically, general coordinate transformations rather than for some arbitrary reason limiting yourself to Lorentz transformations), but physics in Minkowski space is still special relativity, regardless of whether you put curved coordinate grids on it.

@watertommyz

3 жыл бұрын

You need to continue the video, as he intentionally mislead a portion of the video, skipping a rule entirely to prove a point.

@MasterHigure

3 жыл бұрын

@@watertommyz I usually do that. It's been a while, so I did it again just to be safe. And no. He doesn't correct that mistake at all. He just ignores acceleration altogether. So I stand by my criticism: You can deal with accelerated frames of reference in special relativity. He says you can't. That's wrong.

I thoroughly enjoy your 'little crazy'! Keep up the great work!

No one can ever explain better than u Lucid!!! Great Job... But.. wait a minute.. wont that star u mentioned is also moving in galatic plane? If that too considered.. it would be awesome..

A question from the little me: When a particle is "shaking" because or the entropy, from its point of view is that entire univers is moving randomly? And what makes from the point of view of the particle the entire univers to move?

I should say at this point that you r my inspiration for going into a physics major.I know I will struggle with money as u r hence this channel.But I can see the effort u put into these videos such as length contractions in the animations and I hate the system(and also kind of like it being selfish)that you ain't doing some next level physics and earning millions right now.

@ScienceAsylum

6 жыл бұрын

We can always use more physicists :-)

How intriguing! Thank you, I love your videos! 🙂

This channel rocks. Much better than minute physics and all the others.

You did it and that's awesome - best twin paradox explanation out there! As a slow thinker, I watched that Hmm @ 6:57 about 10 times. Hmm, I will probably watch ten times more till this sinks in...and next, let's open that can of warms:-)

As a final episode on Lorentz transformations, you should do a fun video about a space ship going around the earth at 99% speed of light. Space ship is equipped with a radio and a telescope so it can look down the earth and communicate with earthlings. Makes you wonder would they see things on Earth speed up as if someone speed up the video. Or when communicating with Earth, would they be able to talk, since one side would hear speech slowed down, while the other would hear it speed up, i imagine. Doh! This mind experiment opens a can of worms.

@thedeemon

6 жыл бұрын

Yes, they'll see Earth sped up. If they use Skype of Facetime, it would be like the connection is really shitty in rocket-Earth direction (too much lags!) and superfast in Earth-rocket direction (packet overload!).

@DheerajBhaskar

6 жыл бұрын

I would like to hear what crazy scientist guy would say here, reply please? 🙂

@macronencer

5 жыл бұрын

You'd need a REALLY powerful engine to stay in that orbit, as you'd be orbiting several times a second! I wonder how much energy it would require...

THANKS THANKS THANKS Best explanation about the topic on youtube. Thank you, really.

Hey nick, great video once again. I just wanted to ask this : If a frame of reference is accelerating, that just means that we can't apply our transformation laws, right? That's why the twins paradox occurs ; we apply a transformation to a non inertial frame of reference.

@ScienceAsylum

4 жыл бұрын

You can't apply a _Lorentz_ transformation in the accelerating case, but there is a different transformation that works. The point I'm trying to make in this video is that acceleration isn't actually the problem. It's that you need two events in common to compare clocks.

@pranaviyer8178

4 жыл бұрын

@@ScienceAsylum Right! So that's why the twins paradox occurs. Thank you!

As always Nick a brilliant simplification, I was so engrossed that I was shouting at my phone, “No Nick you’ve done the maths wrong”, How stupid of me to think you’d make a mistake like that, hmmmh maybe I’m just a little crazy and not stupid cos at least I spotted the maths. Oooops the flying pig that’s sat next to me has pointed out that it was ‘He’ that spotted the mistake, . . . oh dear . . . Oh dear . . . maybe I’m past being a little crazy . . . Lol

@ScienceAsylum

6 жыл бұрын

HAHA Good thinking! Yeah, I had to do the math wrong upfront or there wouldn't have even been a paradox to talk about.

For my personal interests: this is your best video :) Thank you for making it.

@ScienceAsylum

6 жыл бұрын

You're very welcome :-)

Not related to this. I have often heard that you can't use microscopes that work with light to see something smaller than its wavelength. But I haven't been able to intuitively grasp this. Could you explain this?

@ScienceAsylum

6 жыл бұрын

I might in a future video when I get around to optics.

A large problem is the simplified models used to explain things which cut ever so small corners. When stacking multiple models, those cut corners start adding up fast. For example, speed is stated to be relative. It's really not... If it was, both twins would experience the same thing. Acceleration is absolute and different for each twin since it can be measured within the local frame. And yet, acceleration is not involved in the time difference. Now, to come up with an intuitive model that doesn't cut corners...

@zakelwe

Жыл бұрын

Not sure why he mentioned acceration here to be honest, not needed. Guess it is down to clicks rather than clocks ?

Thanks for another awesome video!

Very satisfied with the solution! And my brain thank you very much for it :)

I think you should make more videos I have finished watching all of them they are super cool and also informative

How do you create and edit clones in your videos? Just curious :D

Lol the Oprah clock bit made me crack up 🤣

without that space/time graph I would've been totally lost.... thanks space/time graph!

Please, please, can you help me understand how travelling in a particular direction or, near the speed of light can affect the flow of 'REAL TIME' (not perceived time)? Isn't Special Relativity akin to claiming, buildings REALLY do shrink as you move away? .

@corwin-7365

4 жыл бұрын

Stu Mas, Time is the rate at which things happen: a burning candle, a ticking clock, a chemical reaction, a beating heart. So anything that physically slows all of those by a uniform amount can be said to have slowed time for that object. Why does moving do that? Atoms are made of charged particles (electrons and nucleus), and so are held together by (and interact using) electro-magnetic fields. The "speed of light" is the speed of propagation of changes in electro-magnetic fields. So when an atom (or anything made up of atoms, such as a person) moves with respect to that field, they are going to be distorted. If you have a hydrogen atom with its spherical electron orbital, and the atom starts moving, then the orbital will become a flattened sphere and the orbital's rate will slow. The electrical charges are trying to interact with each other using a medium which they are moving relative to.

this is the only thing I'm watching on KZread now thanks for the knowledge...question do you believe that all of the elements that will ever exist naturally already present? or do you think there will be more as time lapses

@ScienceAsylum

6 жыл бұрын

All the elements that _can_ exist, _do_ exist or at least _have_ existed. Once space got large enough and cool enough for atoms to form, it was then possible for all of them to form. That doesn't mean we found them all (we definitely have not), but they exist.

@stevencoles2583

6 жыл бұрын

man that opens up a plethora of ideas and possibilities. thank you for breaking things down so we can understand them especially quantum anything lol. I'm rooting for you In your situation and I'm anxiously waiting the next video!!

THIS CHANNEL NEEDS SUBS

There's a simpler explanation. Ignoring acceleration, there are three paths (which are straight lines). That means there are three observers since in Special Relativity, each straight line has an unique observer. If you draw the light-cone diagrams for each observer, that is, you draw three diagrams, then you realize that there is no paradox. From the point of view of the Earth, there is the outbound trip, where time is running slower and the return trip, where time is running slower. Slow time plus slow time is less than Earth time. For the out bound trip, Earth time is running slower because the Earth is moving away from the rocket. But the return trip must move away from the outbound trip faster than the Earth in order for it to catch up with the Earth. That means its time is even slower. So, normal time for the outbound trip plus even slower time for the return trip is less than the Earth's slow time. And similarly for the return trip. The Earth is approaching, so its time is slower. But the outbound trip has to have travelled faster than the Earth go get away from it. So its time is even slower than the Earth's. Normal time for the return trip plus even slower time for the outbound trip is less than the Earth's slow time.

@ScienceAsylum

6 жыл бұрын

That doesn't really address the problem though because the paradox is there even of the rocket doesn't turn around. If that's the case, there aren't "three observers." There are only two observers and, in that case, the paradox is still there.

@ShawnHCorey

6 жыл бұрын

If the rocket does not turn around, there is no paradox because, like you said in the video, there's only one shared event.

@ytashu33

6 жыл бұрын

Exactly!! This video nails the first part, it is the SECOND shared event (when the twin meet again), which remains unexplained!!. Please see my comment/question as well.

@admiralhyperspace0015

6 жыл бұрын

Sir this is a better explanation.I did the math and it all checks out.THANK you for your comment.

@tommywhite3545

6 жыл бұрын

What? I'll go watch it again (above sounds correct I must say ...)

Amazing! That’s a Good Explanation. Now, Can you do a video about the Maxwell’s Demon?!

I have a question: Why are the formulas for a mechanical oscillator (a mass on a spring) so similar to the formulas for an electrical oscillator (an LC circuit)? Are they governed by the same forces or is it just a coincidence that they have such similar properties?

@ScienceAsylum

6 жыл бұрын

Similar patterns. The "oscillator" is a very generic behavior pattern that we find all over the universe. If the behavior is similar, the formula will be too.

Thanks for explaining And nice video as always

"You're not always calculating what you think you're calculating" is a tattoo-worthy quote.

Piece of diamond, really love the way you explained 😍😍

Is there no means to measure/predict simultaneity? Or events that happen at the same instant (could be 5 years for you but 7 for me from some agreed start time).

The science asylum is the true meaning of life

@Mormielo

6 жыл бұрын

42?

@ScienceAsylum

6 жыл бұрын

The Science Asylum = 42.

@stardust4001

6 жыл бұрын

What is 42

@Mormielo

6 жыл бұрын

Neptune The answer to life, universe and everything.

@bytefu

6 жыл бұрын

+Neptune It's a number

1:07 hahahaha such a cute moment :)

What else is relative to the observer? Are quantum fields this way? Or are we moving through the field at 540mps, or whatever you calculate our speed through the universe to be?

@ScienceAsylum

6 жыл бұрын

Special relativity (relativity involving steady speeds in straight lines) is a fundamental part of quantum field theory.

@ryandavis2388

6 жыл бұрын

Haha so I really do live in my own universe.

Your methods are amazing! Thank you!

@ScienceAsylum

5 жыл бұрын

You're welcome :-)

It's not actually "everyone has their own clock" - but every tiny particle or bundle of energy (quanta) has It's own clock. That we are made up of such a colossal number of these tiny things, and can move about more or less as separate entities, makes it more comprehensible to us.

@ScienceAsylum

5 жыл бұрын

You are correct about each particle having it's own clock, but I feel like that makes things _less_ comprehensible.

@glutinousmaximus

5 жыл бұрын

@@ScienceAsylum Well, yesss, maybe! I love your channel regardless ¯\(ツ)/¯

Thank you so much! Finally it makes sense for me :-)

@ScienceAsylum

5 жыл бұрын

You're welcome! Glad I could help.

Please answer: Less Time passed by rocket in relative to space station. So Rocket had gone in the past of space station or spacestation had gone in the future of Rocket. So, when the Rocket returned, it should have returned to the past of Spacestation and they should have not meet again unless the Rocket TimeTravell forward or the Space ship TimeTravell backward. How "Now" for both become same again though the passenger of the Rocket look younger than the person in Space station.

Do particles slow down when travelling at high speeds? Which makes their internal clocks go by slower?

@silverrahul

2 жыл бұрын

Particles do not slow down. Their passage of time slows down.

@MrCmon113

9 ай бұрын

Locally nothing slows down or accelerates at all. As far as you are concerned, everything is normal about you, no matter your speed, because speed is relative in special relativity.

Best explanation ever. None else could clear it for me.

Also nicks energy is contagious

Just glad that I don't have to sit for Physics exam anymore. Awesome video as always.

I have a question you might not be able to answer what happens if you have 2 clocks governed by a quantum entangled pair of particles so no matter what 1 clock does they both read the same and you have one stationary and the other moving near the speed of light

@silverrahul

2 жыл бұрын

That's not how quantum entanglement works

Great teacher!

Its OK to be a crazy

@controlequebrado4455

6 жыл бұрын

little*

@ScienceAsylum

6 жыл бұрын

Thanks for the clarification Controle Quebrado :-)

The time and space plot can be applied on earth and did not need to go to outer space. Can this paradox be applied on twins on two different continents? What would the be the results in this case?

@ScienceAsylum

3 жыл бұрын

1) The problem with having one twin stay on Earth is that Earth curves spacetime. I was trying to avoid _general_ relativity. 2) You _could_ do a twins paradox across the Earth if the latitudes and/or elevations are different for the two twins. It wouldn't be as dramatic a difference though because the time dilation is tiny. Using rockets makes the time dilation noticeable to human perception.

please make videos on tensors and its relation with GR and EM theory

Science and memes... 😃👍

At 5:04, you show the matrix version of the Lorentz Transformation. I happen to be a teacher of linear algebra and of differential equations, and the format of this is exciting to me because it slots in VERY nicely with the last material that we do in the school year. But, I have a question: On the left side of the equation, you have the prime notation for derivatives. What is the variable that is the independent variable for those derivatives? It doesn't seem like it should be time, since time is actually one of the dependent variables there.

@ScienceAsylum

4 жыл бұрын

Oh, those primes aren't derivatives. In relativity, the standard for "prime" is that it's just a way to label a different set of axes. We can't use subscripts to label different axes-sets because those already mean something else (components of vectors). For derivatives, we have to use the d/dx notation rather than primes.

@corwin-7365

4 жыл бұрын

And if you're wondering why bother to write that in matrix form, it's because the four element [ct, x, y, z] "four position" vector (which locates a point in space and time) isn't the only meaningful four element vector that can be transformed with the Lorentz matrix. There are other ones such as the "four momentum" [E/c, px, py, pz] (which specifies the energy and momentum of an object) that also retain meaning under that transform.

Great video. One really esoteric comment. You don’t need GR to describe relativistic accelerations. A rindler wedge only relies on special relativity.

@ScienceAsylum

2 жыл бұрын

I actually have a plan for a video about "momentarily comoving inertial frames."

How do you measure your v? Which reference frame are you using while calculating it?

@ScienceAsylum

4 жыл бұрын

"v" is always measured relative to _something._ There are 4 v's measured in this example: 2 from the space station's point of view and 2 from the rocket's point of view. This leads to 4 different path lengths I show at 8:08

@corwin-7365

4 жыл бұрын

More specifically, an inertial observer always considers _themselves_ to be stationary (with respect to "space") since they always observe that light moves at the same velocity relative to them in all directions.

@TheOnurcem

4 жыл бұрын

@@corwin-7365 is velocity the total displacement and is a vectoral entity in this case which would be 0 as you return to your starting position. Or is it just some speed which is only scalar? İf it is a vector the time dilation would be none if you make your calculations with v = 0 is it is scalar and your velocity is speed then this calculation adds up and there is a time dilation. What am I missing?

@corwin-7365

4 жыл бұрын

@@TheOnurcem , an instantaneous velocity of an object is the speed (and direction) of an object at a given instant. That can change from instant to instant. Likewise the time dilation at any given instant depends on the magnitude of the velocity at that instant'. One measurement of an "average velocity" over a particular time is the net displacement divided by time, which is what you have mentioned.