Relative Simultaneity and Aging - Freaky Fzx Friday

Einstein's 1st postulate - his starting point - for Special Theory - is that the speed of light is measured the same no matter the speed of the source or observer.  That was based on the Michelson-Morley experiment from 1887.

Einstein's Special Theory of Relativity is so named because it only deals with the special case of objects moving at a constant speed in a straight line.

This point of view - or Frame of Reference - is called an "inertial frame of reference"

So clocks run slow and mass increases and length contracts but only from the external perspective.

Internally everything looks normal and is measured to be normal and IS normal.  That's Einstein's 2nd postulate.

Simultaneous events in one frame of reference might not be simultaneous in another.  Both are correct.

And our final piece of Special Relativity is the Twin Paradox.  It's called a paradox if you are only looking at it from the Special Relativity perspective.

Next time - General Relativity - The real reason that the traveling twin ages more slowly.