Three gravitationally lensed quasars, observed using the Keck Observatory’s adaptive optics system, provide an independent measurement of the Hubble constant, confirming a discrepancy in cosmologists’ understanding of how fast the universe is expanding. Image: G. Chen, C. Fassnacht, University of California-Davis
A group of astronomers led by University of California, Davis has obtained new data that suggest the universe is expanding more rapidly than previously thought.
The study comes on the heels of a hot debate over just how fast the universe is ballooning; measurements thus far are in disagreement.
The team’s new measurement of the Hubble constant, or the expansion rate of the universe, involved a different method. They used NASA’s Hubble Space Telescope (HST) in combination with W. M. Keck Observatory’s Adaptive Optics (AO) system to observe three gravitationally-lensed systems. This is the first time ground-based AO technology has been used to obtain the Hubble Constant.
“When I first started working on this problem more than 20 years ago, the available instrumentation limited the amount of useful data that you could get out of the observations,” says co-author Chris Fassnacht, Professor of Physics at UC Davis. “In this project, we are using Keck Observatory’s AO for the first ...