Determining how rapidly the universe is expanding is key to understanding our cosmic fate, but with more precise data has come a conundrum: Estimates based on measurements within our local universe don’t agree with extrapolations from the era shortly after the Big Bang 13.8 billion years ago.
A new estimate of the local expansion rate — the Hubble constant, or H0 (H-naught) — reinforces that discrepancy.
“For measuring distances to galaxies out to 100 megaparsecs, this is a fantastic method,” said cosmologist Chung-Pei Ma, the Judy Chandler Webb Professor in the Physical Sciences at the University of California, Berkeley, and professor of astronomy and physics. “This is the first paper that assembles a large, homogeneous set of data, on 63 galaxies, for the goal of studying H-naught using the SBF method.”
Ma leads the MASSIVE survey of local galaxies, which provided data for 43 of the galaxies — two-thirds of those employed in the new analysis.