Did the universe expand faster than light

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. '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.' '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.

The 63 galaxies in the sample are at distances ranging from 15 to 99 Mpc, looking back in time a mere fraction of the age of the universe. The surface brightness fluctuation (SBF) technique is independent of other techniques and has the potential to provide more precise distance estimates than other methods within about 100 Mpc of Earth, or 330 million light years. Dark energy comprises about two-thirds of the mass and energy in the universe, but is still a mystery.ДЇor the new estimate, astronomers measured fluctuations in the surface brightness of 63 giant elliptical galaxies to determine the distance and plotted distance against velocity for each to obtain H0. Perplexingly, estimates of the local expansion rate based on measured fluctuations in the cosmic microwave background and, independently, fluctuations in the density of normal matter in the early universe (baryon acoustic oscillations), give a very different answer: 67.4 вђ.5 km/sec/Mpc.ДЄstronomers are understandably concerned about this mismatch, because the expansion rate is a critical parameter in understanding the physics and evolution of the universe and is key to understanding dark energy - which accelerates the rate of expansion of the universe and thus causes the Hubble constant to change more rapidly than expected with increasing distance from Earth. The average from the three other techniques is 73.5 в‘.4 km/sec/Mpc.

This means that for every megaparsec - 3.3 million light years, or 3 billion trillion kilometers - from Earth, the universe is expanding an extra 73.3 в’.5 kilometers per second. Using a relatively new and potentially more precise technique for measuring cosmic distances, which employs the average stellar brightness within giant elliptical galaxies as a rung on the distance ladder, astronomers calculate a rate - 73.3 kilometers per second per megaparsec, give or take 2.5 km/sec/Mpc - that lies in the middle of three other good estimates, including the gold standard estimate from Type Ia supernovae. A new estimate of the local expansion rate - the Hubble constant, or H0 (H-naught) - reinforces that discrepancy.

Did the universe expand faster than light