Dear CC,
-The link refers also to the HST Key Project on the Extragalactic Distance Scale, see
http://www.ipac.caltech.edu/H0kp/
- I have only a scant informal background in astronomy. If asked why the sky is dark at night plain common sense will direct me to suggest the distances from us of the sources of light and maybe also the rate of expansion of the universe.
- Maybe someone more familiar with astronomy can explain what makes the "dark night question" a "cornerstone of modern cosmology"...
DH
