I was checking out this calculator where you can calculate distance to distant astronomical objects from redshift.
Here are some values:
z=0.1 > distance (light travel time) 1.31 billion lightyears
z=0.5 > distance 5.093 billion light years
z=1.0 > distance 7.817 billion light years
z=2.0 > distance 10.404 billion light years
z=4.0 > distance 12.162 billion light years
z=8.0 > distance 13.075 billion light years
z=20 > distance 13.54 billion light years
z=100 > distance 13.704 billion light years
z=1000 > distance 13.72 billion light years
Basically, even if something is infinitely redshifted, using the formula to get distance from redshift that cosmologists use, it will not reside further away than 13.72 billion light years.
Obviously according to reigning theory we should not be able to find something more distant than 13.8 billion light years away.
However, if there is something wrong with the model and there are galaxies out there who sent out the light we now observe for more than 13.72 billion light years we will not be able to identify them using the standard "distance as a function of redshift" formula.
Question: Are there other methods for estimating the "light travel time" that could help identifying hypothetically existing highly redshifted objects/galaxies who sent out the light we now see for more than 13.72 billion years ago?