A new way to measure the #expansionrate of the #universe: #Redshiftdrift

https://phys.org/news/2023-08-expansion-universe-redshift-drift.html?utm_source=nwletter&utm_medium=email&utm_campaign=daily-nwletter

#Redshift #RedshiftDrift
"The Redshift Difference in Gravitational Lensed Systems: A Novel Probe of Cosmology"
by C. Wang, K. Bolejko, G.F. Lewis
🔗https://arxiv.org/abs/2308.07529

#DarkMatter #MOND
"Imagine if you can"
🔗 https://tritonstation.com/2023/02/20/imagine-if-you-can/

"... #Hubble established in the 1920s that galaxies external to the Milky Way existed..." but he did not establish "... that the universe was #Expanding". Hubble showed that #Redshift and distance are correlated.
🔗 https://journals.scholarsportal.info/details/00732753/v41i0002/141_wdteu.xml
Expansion is not proven yet, that's why experiments are planned to measure #RedshiftDrift.

Read the articles, then imagine if you are able that redshift does not mean expansion...

@tomassetti Helbig uses an #EinsteinRing to find the transverse velocity of the #GravitationalLens, but the ring is the image of the entire high-z object. One cannot obtain an accurate redshift for a part of the ring.

Multiple-images are better as in the paper by Wang et al.
🔗 https://doi.org/10.3847/1538-4357/ac98aa
(cited by Helbig) which gives a better description of the #RedshiftDrift measurement.

@GravityGrinch any comment on the simple gravitational lens models used in these papers? Can this work?