2010/12/04 by John B. Miller, Thomas E. Miller, Miller, John B. +10 · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Relativity and Gravitational Theory #astro-ph.CO #astro-ph.IM
paper · pdf · doi:10.48550/arxiv.1012.0871
13 pages, 4 figures
arxiv created 2010/12/04 · openalex publication_date 2010/12/04 · arxiv updated 2010/12/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report the first direct photon velocity measurements for extragalactic objects. A fiber-optic, photon time-of-flight instrument, optimized for relatively dim sources (m 12), is used to measure the velocity of visible photons emanating from galaxies and quasars. Lightspeed is found to be 3.00±0.03×108 m s-1, and is invariant, within experimental error, over the range of redshifts measured (0≤ z≤1.33). This measurement provides additional validation of Einstein's theory of General Relativity (GR) and is consistent with the Friedmann-Lemaître-Robertson-Walker (FLRW) metricl, as well as several alternative cosmological models, notably the hyperbolic anti-de Sitter metric, though not with the pseudo-Euclidean de Sitter metric.