Universal age paradox
Two most straightforward methods of computing the age of the Universe through redshift measurements, and stellar evolution yield incompatible results. Recent (mid 1990s) measurements of distances of distant galaxies by the use of the Hubble Space Telescope mention an age much less than the ages of the oldest stars which we calculate through stellar evolution theory . Currently there is no result to this paradox; a cosmological constant would rectify the condition, but it's possible that the discrepancy will not appear along with more accurate measurements of the age of the Universe by both methods.