  For over 20 years NASA has struggled to find an explanation to the Pioneer
anomaly. Now it becomes clear the solution to the riddle is that they have
uncovered evidence that c, the speed of light, is not quite a universal
constant. Using J. C. Cure s hypothesis that the index of refraction is a
function of the gravitational energy density of space and straightforward
Newtonian mechanics, NASA s measurements provide compelling evidence that the
speed of light depends on the inverse of the square root of the gravitational
energy density of space. The magnitude of the Pioneer anomalous acceleration
leads to the value of the primordial energy density of space due to faraway
stars and galaxies: 1.0838. x 10^15 Joule/m3. A value which almost miraculously
coincides with the same quantity: 1.09429 x 10^15 Joule/m3 derived by J. C.
Cure from a completely different phenomenon: the bending of starlight during
solar eclipses.
