In the lead article of last quarter's Facts & Faith (vol 8, no. 4), I reported on a widely publicized conflict over the value of the Hubble constant (that's a number indicating how fast the universe is expanding). As I stated in that article, a recent set of measures indicated a larger number, i.e., a faster expansion rate, hence an apparently younger universe (by a few billion years), than has been generally accepted.
A newer measurement, however, favors the lower Hubble number and sets an upper limit on the Hubble constant that falls between those proposed by both the high number and low number groups.[1] At the same time, this new measurement aligns more closely with other cosmic age indicators (those considered more reliable), such as stellar burning rates and the decay rates of radiometric elements.
This most recent measurement is based on a new technique (called "gravitational lensing"), different from the technique used by either of the two "warring" research groups. Thus, though it surely manifests its own inaccuracies, or calibration errors, it can at least serve as a check and balance on the other Hubble measurements.
As I read about the ongoing research, I estimate that another three or more years of research will be required to resolve this expansion rate controversy. And when it is resolved, the creation date it affirms will be so near to the date already suggested as to make no significant change in our origins model.
Diagram of gravitational lensing. Light from the distant object is bent by gravity as it passes through an intervening galaxy or galaxy cluster (i.e., a "lens").
1. H. Dahle, S. J. Maddox, and Per B. Lilje, "Deep Imaging of the Double Quasar QSO 0957+561: New Constraints on Ho," Astrophysical Journal Letters,#435 (1994), pp. L79-L82.
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