I review here recent developments which have affected our understanding of both the absolute age of globular clusters and the uncertainties in this age estimate , and comment on the implications for cosmological models .
This present estimate is in agreement with the range long advocated by David Schramm .
The major uncertainty in determining ages of globular clusers based upon the absolute magnitude of the main sequence turn-off remains the uncertainty in the distance to these clusters .
Estimates of these distances have recently been upwardly revised due to Hipparcos parallax measurements , if one calibrates luminosities of main sequence stars .
However , it is important to realize that at the present time , different distance measures are in disagreement .
A recent estimate is that the oldest clusters are 11.5 \pm 1.3 Gyr , implying a one-sided 95 \% confidence level lower limit of 9.5 Gyr , if statistical parallax distance measures are not incorporated .
Incorporating more recent measures , including Hipparcos based statistical parallax measures , raises the mean predicted age to 12.8 \pm 1 Gyr , with a 95 \% confidence range of 10-17 Gyr .
I conclude by discussing possible improvements which may allow a more precise age distribution in the near future .