Twins Paradox
The Twins Paradox is a famous thought experiment showing a confusing potential outcome of time dilation predicted by Special Relativity.
None of the academics writing answers in either of these physics.stackexchange threads (one referencing the other) seem to be able to provide a satisfactory explanation of the Twins Paradox:
- https://physics.stackexchange.com/questions/620066/twin-paradox-in-sr
- https://physics.stackexchange.com/questions/2554/how-is-the-classical-twin-paradox-resolved
But, predictable responses to this Relativity Challenge do receive good coverage. A whimsical overview of these arguments are addressed in the satire Relativity Facepalm.
Before Einstein's theories of relativity, a universal frame of reference was generally accepted and has never been entirely disproven. What's known today as the Lorentz Ether Theory (LET) is a common alternate theory to relativity: The Twin Paradox in Special Relativity and in Lorentz Ether Theory