Length Contraction Explained
ฝัง
- เผยแพร่เมื่อ 1 ต.ค. 2024
- Relativity is the idea that time and space can behave differently depending on your perspective. It is notoriously difficult to understand, but in this series, I explain the methods that helped me understand it to the best of my ability. This episode covers length contraction, where the lengths of objects change depending on velocity.
Intro Song: Chopin's Nocturne op 9 no 2, performed by Frank Levy
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Outro Song: Tchaikovsky's Waltz of the Flowers, from youtube's media library
This is the best explanation of why the speed of light is not a limit on itself. I've seen many times ridicilous explanations like "it takes infinite energy" or "the mass increases". The truth is, that when we are moving close to the speed of light, the contracted lenght becomes so short, that we are able to travel huge "uncontracted" distances. Like entire galaxies. From your perspective, you could travel entire galaxy in any time you like, for instance, 1 day, because you are moving through contracted space with huge speed. But from the observer's perspective, it would still take like 100000 years. And at the end, you would realize, that time dilation affected you, and you, in fact, have travelled 100000 years, but for you, only 1 day would pass by. Time dilation and lenght contraction might seem to be counterintuitive, but they are direct consequences of light travelling at the same speed for any observer, and nothing more. Your channel is highly underrated, and this video - very well put together in explaining the subject. I subscribed.
J
These relativity videos are great! After listening to hours of lectures and reading a ton I was still struggling with some concepts that you cleared up in an hour. I will sleep better tonight! You make me feel like I can almost grasp the math even---thank you for sharing this, I anxiously await the next one!
Thank you so much! It's comments like these that make me feel like it's all worth it :)
Don’t let people assume your gender. If they _really_ were experts in science, they would know that they cannot even observe your length. It’s _your_ perspective that matters! 💛🤍💜🖤
(Note for others: Kuvina’s pronouns are _they/them_ and they are shown with the non-binary flag at the start of the video. Please be respectful.)
Also, some annoying people tend to assume gender based on the length of _something._ Now you can tell them that length exists on a spectrum *_and_* is subject to relativity! (And it’s private, and just one of many variables.)
These lectures are really helpful, I would not even mind paying for them. Have you considered Patreon?
Thank you! I do not have a patreon and that is because I don't need the money. But if I do decide to do youtube full time I will consider it.
@@KuvinaThank u so much for your generosity and kindness to spread out knowledge ❤
This is the best explanation I've seen explaining time dilation and length contraction and their direct correlation. I've seen a dozen or more videos and this is the best one. Thanks!
love you so much, you explain it better than any teacher:)
Is there any way to move to make something longer? Like if I run backwards? Or can I shake my hips in a certain way? I have heard lots of $$$ can cause certain things to undergo a Lorentz transformation. Asking for a friend...
took me a bit but I finally get it. Another great video ❤ thank you & keep up this series please 😊
This also solves the "direction of the photon clock" paradox from the second video.
6:30 That was an incredible explanation
I find it really interesting that relative simultaneity applies to time, but not to space. Both space and time experience the same "length contraction", dilating them across spacetime. And yet, spacial dilation preserves coincidence within spatial dimensions, but temporaral dilation does not for the time dimension.
Really great video, thanks for sharing!
OMG you are so so talented in explaining stuff and keeping the intrigue, really thank you for your videos!!
0:35 - 😮Excellent explanation. Makes more sense now.
hm, so what im getting as the main summation of relativity, is that each perspective is just a different way to get to the same answer, and if the answers are different, that means theres just a rule you dont know yet.
can you do a video explaining how gravity is not a force? 🙏❤
long time no see dude :3
i totally support you coming out btw
Another hint to help figure out the ladder paradox:
(click to reveal)
Imagine that the shack has a door on each side that we can instantly open or close. One of the events is when the tail end of the ladder passes through the entrance door so we cqn close it behind the ladder. What could be the other event?
Einstein thought that the math regarding this did not accurately describe physical reality. A graph illustrates the squared nature of dilation (sometimes called gamma or y), dilation increases at an exponential rate the closer you get to the speed of light.
The best way to understand the phenomenon is to imagine a spaceship traveling at a constant acceleration rate. When the ship reaches 50% light speed, as viewed from an Earthbound observer with a magically powerful telescope, it would appear normal because as the graph shows nothing has changed at that point.
When the ship reaches 75% light speed it would appear fuzzy because as the graph shows relativistic effects would be noticeable at that point.
When the ship reaches 99% light speed it would not be visible because every aspect of its existence would be smeared through spacetime relative to an Earthbound observer, not onto itself.
this is so cool!!!!!!
Good stuff, please continue this series!
Thank you so much for making this video !!! I’ve been watching three videos about this topic and this one is the best one yet. the equation helps me understand so much
0:03 what is the flag in your character?
It's the non-binary flag
what if the mover was spinning around the stayer but the stayer was in unison with the mover (similar to how the center of a wheel has the same rpms as the outside of the wheel) would this mean that the stayer observing the mover would see the mover contract?
Yes I do believe so. Even when they have the same angular velocity, the one further out will have a different radial velocity than the one closer to the center. So they each see the other one moving at some velocity, and getting contracted along the direction of motion. However, circular motion is a form of acceleration, which makes it not an inertial reference frame. So in addition to the effects of special relativity, you also will have effects from general relativity.
Does length contraction even mean anything if everything that could measure length is also contracted
OOOOOOOOOH IT'S TIME DILATION WITHIN A REFERENCE FRAME.
Does that mean they can never happen at the same time though
omg i cant wait for the next episodeee
Thank you for your explanation and for your interesting video.
I would like to tell you about this scenario.
A spaceship moves in the frame of the Earth, and travels a distance L. (to reach a star S, suppose the Earth-star distance is L in the frame of the Earth)
The nose of the spaceship (the astronaut twin) and the Earth twin occupy the same position at the initial times (t = t’ = 0)
... and the twins are in relative motion to each other at speed v.
If we consider the uniform linear motion of the spaceship in the frame of the Earth:
1) the astronaut twin reaches the star S at time t = L/v, in the frame of the Earth
2) the star S reaches the astronaut twin at time t’ = L / (gamma*v) in the frame of the spaceship
In the spaceship frame the Earth-star distance is CONTRACTED, YOU'RE RIGHT !
But in my opinion if we consider the uniform linear motion of the Earth in the frame of the spaceship, then we need to consider SOMETHING ELSE: in this case it is necessary to consider the uniform linear motion of the star S in the frame of the spaceship.
And if we consider the uniform linear motion of the star S in the frame of the spaceship:
1) the star S reaches the astronaut twin at time t ’ = L/v in the frame of the spaceship
2) the astronaut twin reaches the star S at time t = L / (gamma*v) in the frame of the Earth
In my opinion the uniform linear motion of the star is hidden but it exists and happens, do you agree ?
NOOOOOOOOO i gotta find out about the ladder
Doesnt the speed of light change relativity, like you can find objectively how fast you are going by checking how close you are to C
No the basic postulate of relativity is that c will always be the same to all observers in inertial reference frames, and that's what everything else arises from. When we talk about something traveling at a certain fraction of c it only appears to be the case for an outside observer. To the object itself it would appear that light is still c faster than itself.
@@hedgehog3180 so travelling 0.99c is the same as travelling 0c technically
Relativity is just an optical illusion, and because all of modern physics is based on Relativity, modern physics is fundamentally wrong and needs to be rethought. Relativity has a simple built in logical fallacy, and no theory based on a logical fallacy can be true, no matter how many experiments seem to prove it, or how many people say it is true. Below is a very simple logical argument highlighting the logical fallacy, using the same terminology Einstein used to derive Relativity.
According to Relativity, observers on a moving train and on a stationary train platform will disagree on the size of the ""Train"" and the passage of time on the ""Train"". This is a complete logical contradiction if the size and the passage of time of the train are real. If the size of the train is real, then the ""Train"" can not be both contracted and not contracted. The same goes for the observed passage of time on the ""Train"". If these effects are observed, then the only possible conclusion is that it is an optical illusion. Things that are real must appear to be same from all frames of reference. If not, then by definition it is an illusion.
Again the argument is very simple and it is the argument Einstein used to derive Relativity, and no acceleration is used in the argument. A train with length (L) traveling at constant velocity (v) relative a stationary observer on a station platform. According to Relativity, the stationary observer will see the train contracted (L/r, where r is the Relativistic gamma), whereas an observer on the train will see it not contracted (L). So the train is both contracted (L/r) and not contracted (L) depending on the observer. This is a complete contradiction (L not equal L/r) and can not be true if length is real. The same argument applies to passage of time on the Train, where both observers will disagree on the passage of time. If time is real, it can not be both dilated and not dilated (T not equal rT). If space and time are observed to be both large and small simultaneously for one inertial reference frame, such as the ""Train"", then it must be an optical illusion.
This argument is only the tip of the iceberg. There is much more evidence including both theoretical and experimental, so please keep reading. Hi my name is Dr William Walker and I am a PhD physicist and have been investigating this topic for 30 years. It has been known since the late 1700s by Simone LaPlace that nearfield Gravity is instantaneous by analyzing the stability of the orbits of the planets about the sun. This is actually predicted by General Relativity by analyzing the propagating fields generated by an oscillating mass. In addition, General Relativity predicts that in the farfield Gravity propagates at the speed of light. The farfield speed of gravity was recently confirmed by LIGO.
Recently it has been shown that light behaves in the same way by using Maxwell's equations to analyze the propagating fields generated my an oscillating charge. For more information search: William Walker Superluminal. This was experimentally confirmed by measuring radio waves propagating between 2 antennas and separating the antennas from the nearfield to the farfield, which occurs about 1 wavelength from the source. This behavior of gravity and light occurs not only for the phase and group speed, but also the information speed. This instantaneous nature of light and gravity near the source has been kept from the public and is not commonly known. The reason is that it shows that both Special Relativity and General Relativity are wrong! It can be easily shown that Instantaneous nearfield light yields Galilean Relativity and farfield light yields Einstein Relativity. This is because in the nearfield, gamma=1since c= infinity, and in the farfield, gamma= the Relativistic gamma since c= farfield speed of light. Since time and space are real, they can not depend on the frequency of light used. This is because c=wavelength x frequency, and 1 wavelength = c/frequency defines the nearfield from the farfield. Consequently Relativity is an optical illusion. Objects moving near the speed of light appear to contract in length and time appears to slow down, but it is just what you see using farfield light. Using nearfield light you will see that the object has not contracted and time has not changed. For more information: Search William Walker Relativity.
Since General Relativity is based on Special Relativity, General Relativity must also be an optical illusion. Spacetime is flat and gravity must be a propagating field. Researchers have shown that in the weak field limit, which is what we only observe, General Relativity reduces to Gravitoelectromagnetism, which shows gravity can be modeled as 4 Maxwell equations similar in form to those for electromagnetic fields, yielding Electric and Magnetic components of gravity. This theory explains all gravitational effects as well as the instantaneous nearfield and speed of light farfield propagating fields. So gravity is a propagating field that can finally be quantized enabling the unification of gravity and quantum mechanics.
The current interpretation of quantum mechanics makes no sense, involving particles that are not real until measured, and in a fuzzy superposition of states. On the other hand, the Pilot Wave interpretation of Quantum Mechanics makes makes much more sense, which says particles are always real with real positions and velocities. The particles also interact with an energetic quantum field that permeates all of space, forming a pilot wave that guides the particle. This simpler deterministic explanation explains all known quantum phenomena. The only problem is that the Pilot Wave is known to interact instantaneously with all other particles, and this is completely incompatible with Relativity, but is compatible with Galilean Relativity. But because of the evidence presented here, this is no longer a problem, and elevates the Pilot Interpretation to our best explanation of Quantum Mechanics.
*TH-cam presentation of above argument:
th-cam.com/video/sePdJ7vSQvQ/w-d-xo.html
*Paper it is based on: William D. Walker and Dag Stranneby, A New Interpretation of Relativity, 2023: vixra.org/abs/2309.0145
Your example with a train isn't a contradiction, you just personally find it unintuitive but you haven't shown any contradiction merely asserted that you don't like the facts. Personal taste however is not a valid argument in science.
@@hedgehog3180 No, it is a logical proof and has nothing to do with opinion. The same object can not be both larger and small at the same time and be physically true. Sure it can appear that way due to a physical illusion at play. For instance the object can be rotated at different angles from both observers perspectives. But using observation and physics reasoning we can figure out that the object has a real size that both observers must agree on, and it is just rotated creating a physical illusion that it appears to be a different size depending on the orientation of the observer. The size of an object is something physical and must be the same for all observers.