Hi,
Seeing the Galaxy UGC 3374 or PGC 18078 in my wide field image taken with the Taka TOA 130 curiosity did me search in the NASA/IPAC webpage for its details and saw that there is a huge discrepancy in distance.
Hubble Distance is ~90.67 Mpc ~ 295 mly
Redshift-independent Distances is ~170.55 ~ 556 mly
Is it allowed here to ask, what is correct?
Pure curiosity
Thanks
andrea tasselli · Jan 9, 2026, 09:56 PM
Reading it a bit in depth would clarify the question:
One is the distance estimated by the optical redhshift and current cosmological constants while the other is another estimate of the distance without using this information (using 21cm HI line spectra widening). It shall not pass unnoticed that the error bracket for the latter return the previous value to a good precision, wiz:
Hi Andrea,
Thanks. I read your message many times and still do not underatand it fully. My conclusion is then that both values are correct but also wrong and none of them is the correct distance of the object, eg. we do not know the real distance.
I have seen it in a few of the objects I image that there are two distances very different while on other objects these two values have a minor discrepancy.
Yes, I ahve read a lot of articles about Hubble Distance, Hubble Constant and Redshift-Independent Distances, etc. etc. etc. but still need to read more to get a clearer image…
andrea tasselli · Jan 10, 2026, 05:29 PM
CBR
What is this?
Just found an answer from AI after asking
“when a galaxy has two different distances like Hubble distance and redshift independent distance, which one is correct?”
Answer from AI ( I am still reluctant to take for granted what AI delivers but a bit of truth must lie in there)
📷 image.png
Below an interesting article