When we observe astronomical objects like distant galaxies there are several complicating factors for estimating the distance:
- Relativistic speed result in length contraction
- Relativistic speed results in Doppler-shifts in the frequency of light
- Simultaneity is skewed due to our differing velocities
With these effects, how are we able to state with decent accuracy how far away all of the distant galaxies are from us? Do the above effects have an impact on the measurements?
I know that determining far distances is mainly done by measuring the red-shift of light from those sources. A higher z number normally means it is farther away (due to the accelerating expansion of the Universe). My question is really about how relativistic effects are accounted for and whether or not they play a big role in the uncertainty of our calculations.
I'm looking for an answer geared towards the layperson, but formulas are always a welcome challenge.