“Measuring Shadows” –Revising the Expansion Rate of the Cosmos


Hubble's Constant


“Eventually we reach the utmost limits of our telescopes –there we measure shadows, and we search among the ghostly errors of measurement for landmarks that are scarcely more substantial,” said Edwin Hubble in 1929, creator of Hubble’s law that observed that the further galaxies are, the faster they are moving away from Earth –the “red shift.” Predictions of Hubble’s Constant from the standard cosmological model when applied to new measurements of the cosmic microwave background (CMB)—the leftover radiation from the Big Bang—have produced a value of 67.4, a significant and troubling difference. This difference, which astronomers say is one of the fundamental problems in all of physics, is beyond the experimental errors in the observations.