Symmetrical Twin Paradox resolved with dynamic Minkowski Spacetime Diagram (Lorentz Transformations)
Channel: TwinParadox
Date: 2022-08-28

CONCLUSION: THE TWIN WHO TRAVELS A GREATER DISTANCE IN SPACE-TIME (between separation and reunion) IS THE TWIN THAT AGES MORE SLOWLY !!!
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00:00 Intro
01:10 The conventional explanation and resolution of the Twin Paradox
06:03 Reversing the Paradox
07:45 Why acceleration cannot be the cause of the time dilation
09:48 If they both fly towards each other to meet half way, then they will both end up with the same age.
11:21 Clocks observed at a distance first appear at half speed but then at double speed (Doppler effect).

In this video I show various ways we can resolve the apparent asymmetry in the Twin Paradox, using a visual version of the Lorentz Transformations on a Minkowski Spacetime Diagram. I also show that the Twin Paradox can be reversed, so that the first twin who originally stayed on Earth leaves to catch up with and meet his brother, making the first twin be the one who ages more slowly compared to the twin who left Earth first.

The dynamic Minkowski spacetime diagram used in this video was created by Abdul Latiff and can be found here: https://www.geogebra.org/m/s7xsubde

X-Axis: Distance, in light-years 
Y-Axis: Time, in years
Red Dot 🔴: a hypothetical star 3 light years from Earth
Green Dot 🟢: Earth 10 years later, when the second twin returns.

A brilliant article by Ronald C. Lasky explaining how the clocks look to the distant twins and how they first appear to slow down to half speed but then in the second "half" speed up to double speed, can be found here: https://www.scientificamerican.com/article/does-time-tick-at-the-same-rate-for-everyone/

You can verify the other speeds I talk about in the video:
88% of the speed of light to catch up with the twin who is traveling at 60% of the speed of light: https://www.omnicalculator.com/physics/velocity-addition?v=v:0.6!c,w:0.6!c
33.333% of the speed of light if both twins accelerate apart from each other at the beginning: https://www.omnicalculator.com/physics/velocity-addition?v=v:0.3333!c,w:0.3333!c

And heres one of the best explanations I've found of Minkowski spacetime diagrams, geometric Lorentz Transformations, and how to interpret them: https://youtu.be/1YFrISfN7jo

EDIT: After uploading this video, I did find one other video using at least in part very similar explanations and diagrams, including the Doppler effect (without referring to it in those precise terms):
- https://youtu.be/KdjQkuGTBMo?t=19m35s