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Jennifer Ouellette reports via Ars Technica: Astronomers have made new measurements of the Hubble constant, a measure of how quickly the Universe is expanding, combining data from the Hubble Space Telescope and the James Webb Space Telescope. Your results confirmed the accuracy of Hubble’s previous measurement of the value of the constantaccording to his recent article published in The Astrophysical Journal Letterswith implications for a long-standing discrepancy in values obtained by different observation methods known as the “Hubble tension”.
There was a time when scientists believed that the Universe was static, but that changed with Albert Einstein’s general theory of relativity. Alexander Friedmann published a set of equations showing that the Universe could actually be expanding in 1922, and Georges Lemaitre later made an independent derivation to reach the same conclusion. Edwin Hubble confirmed this expansion with observational data in 1929. Before this, Einstein had been trying to modify general relativity by adding a cosmological constant to obtain a static universe from his theory; After the discovery of Hubble, Legend says, referred to that effort as his biggest mistake. The article notes how scientists have employed different methods to calculate the Hubble constant, including observing nearby celestial objects, analyzing gravitational waves from cosmic events, and examining the cosmic microwave background (CMB). However, these approaches yield different values, highlighting the challenge of pinpointing the constant precisely. A recent effort involved making additional observations of Cepheid variable stars, correlating them with Hubble data. The results further confirmed the accuracy of the Hubble data.
“We have now covered the full range of what Hubble observed and can rule out measurement error as the cause of the Hubble strain with very high confidence.” saying Co-author and team leader Adam Riess, a physicist at Johns Hopkins University. “The combination of Webb and Hubble gives us the best of both worlds. We find that Hubble measurements remain reliable as we move up the cosmic distance scale. Once measurement errors are negated, what remains is the real possibility and exciting that we have misunderstood the Universe.”