What happens to errors in the initial rungs of the cosmic distance ladder?
The error is magnified exponentially as the measurement extends to farther galaxies.
The structure of the cosmic distance ladder dictates a severe penalty for initial measurement inaccuracies, particularly those found in the lowest rungs, such as measurements derived from parallax for nearby stars. Because each subsequent measurement relies on the calibration established by the previous, closer measurement, any small percentage of error present at the start—for instance, a 1% error in measuring a nearby star—is compounded or magnified with each step outward. When extended across billions of light-years to the farthest observable structures, these initially negligible errors translate into massive discrepancies, potentially spanning millions or billions of light-years in the final calculated distances.
