Length Contraction and Time Dilation | Special Relativity Ch. 5
Why Physics Stack Exchange recommends it
Physics Stack Exchange users link it to show, with a diagram, why relativistic effects are symmetric between observers and how the Lorentz transformation produces them.
Recommended by 3 people across 3 different months, 2019 to 2020.
What it is
A 7-minute minutephysics video, chapter 5 of Henry Reich's special relativity series, explaining length contraction and time dilation. It uses a mechanical Minkowski diagram, or spacetime globe, to show how the Lorentz transformation of event coordinates produces both effects.
What people said
Recommends Matt · 2019-06 · Physics Stack Exchange · on “Shooting someone's past self using special relativity”
You suppose that A and B are far apart "initially" and that they were "both aged 0 when B took off". It means that you assume that simultaneity is an absolute notion, independent of the frame of reference, which is why you come to a paradox. It is exactly the symetric case of two people starting at the same point, diverging fast, and observing each other: each one will see the other one aging slower than him, because they compare moments in non parallel time sections. This is best shown by a drawing, this is the one I have suggested in this thread [LINK] : link to a video at the second displaying the graph [this video] .
Recommends Matt · 2019-06 · Physics Stack Exchange · on “Hypothetical effect of Solar System/Orion Spur traveling near speed of light”
@Thomas OK, I have found the picture I wanted to draw for you, in a video. This is the link with a time tag exactly at the moment when it appears: [this video] It should clear your mind on how the situation can be symetric (which is not possible if you hold on absolute time, simultaneity and all those things, of course).
Recommends Sean E. Lake · 2019-11 · Physics Stack Exchange · on “Checking the Lorentz Invariance”
@Constantin I recommend watching this playlist [LINK] , especially the Lorentz transform [LINK] video and the length contraction/time dilation video [this video] . Bottom line: the formula you want to depend on is a special case that only works sometimes.
Recommends rim · 2020-08 · Physics Stack Exchange · on “In relativity, if units of length contracts and time dilates then does unit of velocity or speed also change?”
Along with Philip’s answer, this video ( [this video] ) brought clarity to the problem. Basically what I understood from the two is that time dilation and length contraction are not similar or symmetrical things (as I was assuming in original question) but by nature, we are able to measure time only using one and length using another method respectively. In fact, there are concepts of length dilation and duration contraction that are not generally discussed but should be.
Cites Our · 2020-04 · Physics Stack Exchange · on “"If something moves while you are measuring its length, it does not represent its length": why?”
In minutepysics, while explaning length contraction [this video] , it is stated that If something moves while you are measuring its length, it does not represent its length Question: Why? I, somewhat, know that "measuring the length of an object while moving" does not work from this question [LINK] , but I cannot understand why that is the case; after all, we do a lot of length measurements by lasers, by which we use the time difference between laser beams arriving at different times.