Have we measured the change in the red shift over time?

[Justin Hunt]

Have experiments been done to measure the red shifts of distant objects over time? If inflation is correct, the the speed at which an object is receding relative to us is based on how far away that object is located. Therefore, the most distant objects would also have the highest acceleration. Is it possible to measure a change in red shift of distant objects due to this acceleration?

I am a bit of a skeptic of the expanding universe conclusion we derived by comparing red shift values to brightness when it could be explained with actual velocities versus expansion of space time or some combination of the two. In my opinion testing changes in red shift over time would be the most decisive way to determine what part of the velocity is due to actual velocity and what part is due to the expansion of space between us and the distant object.

 

[George Jones]

Have experiments been done to measure the red shifts of distant objects over time? If inflation is correct, the the speed at which an object is receding relative to us is based on how far away that object is located. Therefore, the most distant objects would also have the highest acceleration. Is it possible to measure a change in red shift of distant objects due to this acceleration?.

This is called redshift-drift, and it occasionally come up here at Physics Forums. See,

https://www.physicsforums.com/threa...or-cosmological-redshift.617506/#post-3981620

https://www.physicsforums.com/threads/possible-way-to-measure-dark-energy.826976/#post-5194025

 

[kimbyd]

I am a bit of a skeptic of the expanding universe conclusion we derived by comparing red shift values to brightness when it could be explained with actual velocities versus expansion of space time or some combination of the two. In my opinion testing changes in red shift over time would be the most decisive way to determine what part of the velocity is due to actual velocity and what part is due to the expansion of space between us and the distant object.

There's no difference between the description of our universe as "stuff is moving apart" and "space is expanding". They're two different ways of describing the exact same phenomenon. Each description has strengths and weaknesses in terms of providing understanding of what's going on.

 

[Chronos]

Keep in mind the rate of expansion is absolutely microscopic compared to the size of the universe. The Hubble constant is about 70 km/sec/MEGAparsec. That translates into about 7x10^-9% per year. We cannot measure redshift with such phenomenal accuracy - even at vast distances over many, many years. Scientists have come up with a very clever effortt using gravitational lensing as described here; https://arxiv.org/abs/1703.05142, Redshift drift of gravitational lensing