Astronomers more accurately determine the rate of expansion of the universe

Scientists have specified the expansion rate of the local universe. The results of the study are published in The Astrophysical Journal.

NGC 1453, a giant elliptical galaxy in the constellation Eridani, was one of 63 galaxies used to calculate the expansion rate of the local universe.

Determining how fast the universe is expanding is a way to understand how it evolved and what lies ahead. But with more accurate data, a problem has arisen: estimates based on measurements in our local universe do not agree with extrapolations from the era shortly after the Big Bang 13.8 billion years ago.

The new estimate of the rate of local expansion – the Hubble constant, or H0 (H-nothing) – amplifies this discrepancy.

The new H0 value emerged as a by-product of the MASSIVE survey of nearby galaxies, in which scientists use space and ground-based telescopes to study in detail the 100 most massive galaxies within about 100 megaparsecs, or 330 million light-years from Earth.

To obtain H0, scientists from the MASSIVE project measured fluctuations in the surface brightness of 63 giant elliptical galaxies and determined the distance to each of them depending on their speed.

The authors note that the advantage of the surface brightness fluctuation (SBF) method is that it does not depend on other parameters or methods of observation and can provide more accurate distance estimates than other methods.

As a result, the value of the Hubble constant for a large number of galaxies was 73.3 kilometers per second per megaparsec. This means that for every megaparsec – 3.3 million light years, or 3 billion trillion kilometers – the universe is expanding 73.3 kilometers per second.

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Alexandr Ivanov earned his Licentiate Engineer in Systems and Computer Engineering from the Free International University of Moldova. Since 2013, Alexandr has been working as a freelance web programmer.
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Alexandr Ivanov

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