- #1
bernhard.rothenstein
- 991
- 1
As we know, Bondi derives the Lorentz transformations (LT) via the radar detection of the space-time coordinates of a distant event.
Once derived from other starting points the LT should account for the results obtained by Bondi expressing them as a function of the Doppler factor
D=sqrt[(1+b)/(1-b)] which can be derived without using the LT (b=V/c). The outgoing radar signal generates the event E(x,y=0,t=x/c) when detected from I and E'(x'=ct',y'=0,t'=x'/c). In accordance with the LT we have
x=(x'+cbt')/sqrt(1-b^2). (1)
But
b=(D^2-1)/1+D^2
sqrt(1-b^2)=2D/(1+D^2)
with which (1) becomes
x=[x'(1+D^2)+ct'(D^2-1)]/2D=Dx'=Dct' (2)
In a simillar way we obtain
t=[(1+D^2)x'+(D^2-1)x'/c]/2D=Dt'=Dx'/c. (3)
If the event is generated by a tardyon moving with speed u(u') the generated events are
E(x=ut,y=0,t=x/u) and E'(x'=u't',y'=0,t'=x'/u') and the corresponding LT could be espressed again as a function of D.
Do you find flows above? Do you consider that it could be a good exercise for the beginner teaching him to handle the LT?
Thanks in advance for your answers.
Once derived from other starting points the LT should account for the results obtained by Bondi expressing them as a function of the Doppler factor
D=sqrt[(1+b)/(1-b)] which can be derived without using the LT (b=V/c). The outgoing radar signal generates the event E(x,y=0,t=x/c) when detected from I and E'(x'=ct',y'=0,t'=x'/c). In accordance with the LT we have
x=(x'+cbt')/sqrt(1-b^2). (1)
But
b=(D^2-1)/1+D^2
sqrt(1-b^2)=2D/(1+D^2)
with which (1) becomes
x=[x'(1+D^2)+ct'(D^2-1)]/2D=Dx'=Dct' (2)
In a simillar way we obtain
t=[(1+D^2)x'+(D^2-1)x'/c]/2D=Dt'=Dx'/c. (3)
If the event is generated by a tardyon moving with speed u(u') the generated events are
E(x=ut,y=0,t=x/u) and E'(x'=u't',y'=0,t'=x'/u') and the corresponding LT could be espressed again as a function of D.
Do you find flows above? Do you consider that it could be a good exercise for the beginner teaching him to handle the LT?
Thanks in advance for your answers.