Re:Do we really travel through time with the speed of light?
by Filligree on Monday August 31, 2020 @09:11AM
(#24331080)
It's not equal to C, as such.
It's a unit vector, and physicists working with relativity habitually set C=1 to make the equations simpler. That being said, it isn't really a vector -- it's just a direction. The "equal to C" bit is a mathematical artifact of both vectors being normalized.
Re:Do we really travel through time with the speed of light?
by andi999 on Monday August 31, 2020 @09:21AM
(#24331155)
Well, c is the conversion factor between our length and time measurement. For me, I am ok not to measure time in meter, so c can stay.
Re:Do we really travel through time with the speed of light?
by pdonis on Monday August 31, 2020 @01:26PM
(#24333735)
> why is it for all objects equal to c
Because this 4-vector removes the factor of rest mass, which distinguishes objects. Putting back the rest mass converts 4-velocity to 4-momentum, which does not have the same magnitude for all objects--the magnitude is the rest mass.
If you think for stationary examples it just means that the eigenzeit has a different pace, so two clocks next to each other going at a different pace. But this is ruled out by another definition, such that clocks are references by light clocks. And now it is also clear why this invariance is c.