On the use of galaxies as clocks and the universal expansion

Understand

We set out to rederive the 8 Hubble parameter values obtained from estimated relative galaxy ages by Simon et al.

• [Physical Review D, 71, 123001 (2005)].
• We find that to obtain the level of precision claimed in $H(z)$, unrealistically small galaxy age uncertainties have to be assumed.
• Also, some parameter values will be correlated.