This is the key to understanding the Lorentz Transformation.

With COVID-19 putting a damper on social activity, “the gang” doesn’t get together very often, but we still gather occasionally (and carefully). One of the times recently I got into how, even though we’re all sitting essentially motionless in a living room, we’re moving through time at the speed of light. I explained why that was, and they found it pretty cool.

Then I ran into someone online who just couldn’t wrap his head around it — just couldn’t accept it (despite explaining in detail and even providing links to some videos). Physics is sometimes challenging to our daily perceptions of reality!

In this case, though, it’s just a matter of some rather simple geometry.

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