Tuesday, November 16, 2021

Error In Astronomy Distances Is Systemically Understated

Singh's analysis isn't rocket science, just diligent hard work. But it also is robust, is not model dependent, and is frankly the kind of reality check that should be applied to stated error bars experimental and observational results more often.  

Simply put, the Hubble tension is an illusion of us thinking that our extragalactic distance measurements are more precise than they actually are. This also suggests that the values of the cosmological constant and dark energy proportion are far more uncertain than they are generally claimed to be. We are not yet in an era of true precision cosmology as much as we'd like to think that we are.

1. We find that any two distance moduli measurements for the same galaxy differ from each other by 2.07 times the reported one sigma uncertainty on average. 
2. This average difference between distance moduli measurements of the same galaxy as a multiple of reported uncertainty is growing with time of publication, rising to 3.00 times the reported one sigma uncertainty for all distances reported from 2014 to 2018. 
3. This average difference between distance moduli measurements of the same galaxy as a multiple of reported one sigma uncertainty is highest for the standard candles (3.01) including Cepheids (4.26), Type Ia Supernovae (2.85), and Tip of the Red Giant Branch (2.82). 
4. This data points to a possible systematic underestimation of uncertainties in extragalactic distances. 
5. The results also give a possible way out of the Hubble-Lemaitre tension by advocating for increasing the error bars on Hubble-Lemaitre constant measured via distance ladders of standard candles and rulers.
Ritesh Singh, "Evidence for possible systematic underestimation of uncertainties in extragalactic distances and its cosmological implications" arXiv:2111.07872 (November 15, 2021) (published in 366 Astrophys Space Sci 99 (2021) DOI: 10.1007/s10509-021-04006-5).

1 comment:

Graham Dungworth said...

Ritesh Singh conclusions include
"Since
Type Ia Supernovae distances form a critical basis of
cosmological models and expansion history, underesti-
mation of uncertainties in them may have some impli-
cations for our confidence in cosmological parameters... "
It's not necessarily the problem with smoke and dust estimations.

So where does this leave Accelerated Expansion?