How can the oldest stars in the Universe be older than the Universe?
Of course the Universe has to be older than the oldest stars in it. So this question basically asks: which estimate is wrong – • The age of the Universe • The age of the oldest stars • Both The age of the Universe is determined from its expansion rate: the Hubble constant, which is the ratio of the radial velocity of a distant galaxy to its distance. The radial velocity is easy to measure, but the distances are not. Thus there is currently a 11% uncertainty in the value of the Hubble constant measured directly by the Hubble Space Telescope. John Huchra gives a good discussion of the historical uncertainties in the Hubble constant since even before Hubble’s work. There is now a more precise but more indirect determination from WMAP observations of the CMB anisotropy, and a more accurate direct measurement from Riess et al.. The estimated age of the Universe has been increased by the observations of an accelerated expansion of the Universe. The current best value is 13.7 +/- 0.2 billion
