The ages of the oldest stellar objects in our galaxy provide an independent test of the current cosmological model as they give a lower limit to the age of the Universe .
Recent accurate parallaxes by the Gaia space mission , accurate measurements of the metallicity of stars , via individual elemental abundances , and advances in the modelling of stellar evolution , provide new , higher-precision age estimates of the oldest stellar populations in the galaxy : globular clusters and very-low-metallicity stars .
The constraints on the age of the Universe , t _ { U } , so obtained are determined from the local Universe and at late time .
It is well known that local and early-Universe determinations of another cosmological parameter closely related to the age of the Universe , the Hubble constant H _ { 0 } , show a \gtrsim 3 \sigma tension .
In the standard cosmological model , \Lambda CDM , t _ { U } and H _ { 0 } are related by the matter density parameter \Omega _ { m, 0 } .
We propose to combine local t _ { U } constraints with late-time \Omega _ { m, 0 } estimates in a \Lambda CDM framework , to obtain a low-redshift H _ { 0 } determination that does not rely on early Universe physics .
A proof-of-principle of this approach with current data gives H _ { 0 } = 71 \pm 2.8 ( H _ { 0 } = 69.3 \pm 2.7 ) km s ^ { -1 } Mpc ^ { -1 } from globular clusters ( very-low-metallicity stars ) with excellent prospects for improved constraints in the near future .