- #1
ralqs
- 99
- 1
Some time ago, I came across a nice justification (by Einstein IIRC) for the formula [tex]x'^2 + y'^2 + z'^2 - c^2t'^2 = x^2 + y^2 + z^2 - c^2t^2[/tex].
The argument went something like this:
(1) [tex]x'^2 + y'^2 + z'^2 - c^2t'^2 = x^2 + y^2 + z^2 - c^2t^2 = 0[/tex] for light.
(2) *reasoning I forget*, therefore [tex]x'^2 + y'^2 + z'^2 - c^2t'^2 = \sigma(x^2 + y^2 + z^2 - c^2t^2)[/tex]
(3) [tex]y'^2 = y^2 [/tex], so [tex]\sigma = 1[/tex].
I can't remember or deduce the argument for step 2. I'm guessing it came down to some argument about linearity...does anyone have any ideas? Thanks.
The argument went something like this:
(1) [tex]x'^2 + y'^2 + z'^2 - c^2t'^2 = x^2 + y^2 + z^2 - c^2t^2 = 0[/tex] for light.
(2) *reasoning I forget*, therefore [tex]x'^2 + y'^2 + z'^2 - c^2t'^2 = \sigma(x^2 + y^2 + z^2 - c^2t^2)[/tex]
(3) [tex]y'^2 = y^2 [/tex], so [tex]\sigma = 1[/tex].
I can't remember or deduce the argument for step 2. I'm guessing it came down to some argument about linearity...does anyone have any ideas? Thanks.