Quote:
Originally Posted by Cougar
Apparently, the simple answer is no. According to Harvard's Water Maser Cosmology Project....Today, the best estimate of the Hubble constant is uncertain by perhaps 10% when all things are considered. Of course, in traditional astronomical terms, "uncertain by 10%" is astoundingly accurate. |
Thanks for the link cougar!
One thing to keep in mind when they quote the 10% accuracy is that it really applies to the uncertainty of the individual H0 estimates given the assumptions and methods applied in each study. The actual value of H0 could still be more than 10% different from any of the individual studies that have attempted to estimate H0. For example, Tully&Pierce noted the potential for a 12% change in H0 with the maser distance to NGC 4258.
Ekholm et al find H0=53 in one study. So 10% sets an upper limit of 58 from their methods - consistent with their reported uncertainty. Tully&Pierce find H0=77 and 10% sets a lower limit of 69 - again consistent with their reported uncertainty. So the 10% accuracy doesn't lead to an overlap in the results of the two studies.
My point is just that while the data and calibrators now in principle allow a determination of H0 to 10% accuracy. That H0 value is only accurate to within 10% of the true value of H0 if the assumptions and methods of the study are in fact valid.