New observations by NASA/ESA/CSA’s James Webb Space Telescope confirm previous measurements by the NASA/ESA Hubble Space Telescope of the distances between nearby stars and galaxies, and confirm measurements of the universe’s mysterious expansion. Provide critical cross-checking to address discrepancies. This contradiction, known as the Hubble tension, remains unexplained by even the best cosmological models.
This artist’s impression shows the evolution of the universe, starting with the Big Bang on the left and continuing with the emergence of the Cosmic Microwave Background. The formation of the first stars ends the Dark Ages of the universe, followed by the formation of galaxies. Image credit: M. Weiss / Harvard-Smithsonian Center for Astrophysics.
“The discrepancy between the observed rate of expansion of the universe and the predictions of the Standard Model suggests that our understanding of the universe may be incomplete,” said Nobel laureate and Johns Hopkins University professor Adam Riess. “There is,” he said.
“Now that NASA’s two flagship telescopes are confirming each other’s discoveries, we must take this issue very seriously. It’s a challenge, but it’s a It’s also a great opportunity to learn more.”
The new research builds on Professor Rees’ Nobel Prize-winning discovery that the expansion of the universe is being accelerated by a mysterious dark energy that permeates the vast expanses of space between stars and galaxies.
The authors used the largest sample of Webb data collected during the first two years of the universe to test the Hubble telescope’s measure of the rate of expansion of the universe, a number known as the Hubble constant.
They used three different methods to measure the distance to the galaxy where the supernova occurred, using a method previously measured by the Hubble telescope and known to provide the most accurate “local” measurement of this number. We focused on the distance that is being
Observations from both telescopes were in close agreement, revealing that Hubble’s measurements were accurate and eliminating inaccuracies large enough to attribute the tension to Hubble’s errors.
Still, the Hubble constant remains a mystery. This is because measurements based on current telescopic observations of the universe produce higher values compared to projections made using the standard model of cosmology. The Standard Model is a widely accepted framework for how the universe works, calibrated with cosmic microwave background data. Weak radiation left over from the Big Bang.
The Standard Model Hubble constant is approximately 67-68 km/sec per megaparsec, but measurements based on telescope observations typically yield higher values of 70-76, with an average of 73 km/sec/megaparsec.
This discrepancy has puzzled cosmologists for more than a decade. A difference of 5 to 6 kilometers per second per megaparsec is too large to be explained solely by deficiencies in measurement and observation technology.
Webb’s new data eliminates significant bias in Hubble’s measurements, so the Hubble tension could be due to unknown factors or gaps in cosmologists’ understanding of physics that have yet to be discovered.
“Webb’s data represent the first high-definition view of the universe, greatly improving the signal-to-noise ratio of the measurements,” said Xiang Li, a graduate student at Johns Hopkins University. .
This image, taken with the Nicholas U. Mayall 4-meter telescope, shows the spiral galaxy Messier 106. Two dwarf galaxies (NGC 4248 in the lower right and UGC 7356 in the lower left) also appear in the image. Image credits: KPNO / NOIRLab / NSF / AURA / New Mexico State University MT Patterson / University of Alaska Anchorage TA Chancellor / M. Zamani & D. de Martin.
The astronomers used the known distance to the spiral galaxy Messier 106 (also known as M106 or NGC 4258) as a reference point to cover roughly one-third of Hubble’s total galaxy sample.
Despite the small dataset, they achieved impressive accuracy, showing less than 2% difference between measurements. This is much smaller than the approximately 8-9% size of the Hubble tension mismatch.
In addition to analyzing pulsating stars called Cepheid variable stars, the gold standard for measuring distances in the universe, they cross-checked measurements based on the brightest red giant stars in the same galaxy as carbon-rich stars. .
All galaxies observed by Webb with supernovae yielded a Hubble constant of 72.6 km per second per megaparsec. This is about the same as the 72.8 km per second per megaparsec that Hubble found for the very same galaxy.
“One possible explanation for the Hubble tension is that something was missing in our understanding of the early universe, such as a new component of matter that unexpectedly bombarded the universe after the Big Bang, nascent dark energy. I guess so,” Johns said. Mark Kamionkowski, a cosmologist at Hopkins University, was not involved in the study.
“And there are other ideas that might do the trick, like interesting dark matter properties, exotic particles, changing electron masses, or primordial magnetic fields. Theorists have a right to be pretty creative. It is.”
of result Published in astrophysical journal.
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Adam G. Reese others. 2024. JWST validates HST distance measurements: Supernova subsample selection explains differences in JWST estimates of local H0. APJ 977, 120; doi: 10.3847/1538-4357/ad8c21
Source: www.sci.news
