Theoretical Extent of Redshift - How Far Can It Go?

[Wes Tausend]

How far can the Redshift phenomenon theoretically shift frequency? I believe I understand the doppler-like effect, but have never seen this question regarding extreme RF shift asked before.

One might think that if a relative object moved away very near the speed of light that the radio emission frequency might drop so low as to be very near subsonic levels. Or perhaps zero frequency at full lightspeed, if the weakened signals were somehow still detectable.

Thanks,
Wes
...

 

[phinds]

I can't see any reason why there should be a lower limit.

 

[TheDemx27]

Well, if you look up the equation for the relativistic doppler effect, you will get something like this. If you plug in 299,792,457 m/s for v (1 m/s less than c), and let v_source be 1, you get a factor 24486.427. Hopefully this is what you meant?