A study of more than 25 million galaxies reveals strange discrepancies in the way astronomers measure the cosmological lumpiness, the cosmological standard that explains how the universe formed and evolved. This may threaten the model.
The discrepancy, discovered by measuring the distortion of light caused by the powerful gravitational fields of distant galaxies, suggests that the universe is not as dense as previously predicted.
If the measurements are accurate, it could join the Hubble tension as another significant challenge to our preconceptions about how the universe evolved, paving the way for new physics and even completely different models of the universe. It may be given away. The researchers published their findings in the journal Dec. 11. Physical Review D.
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“We’re still pretty cautious here.” Michael Straussdean of Princeton University’s School of Astrophysical Sciences and one of the leaders of the team that made this discovery. stated in a statement. “We are not saying that we have recently discovered that modern cosmology is all wrong; statistics show that there is only a 1 in 20 chance that it is due to chance, and this is It’s powerful, but not completely conclusive: the astronomical community has come to the same conclusion through multiple experiments, and as we continue to make these measurements, we’re probably finding out it’s real. ”
According to the standard model of cosmology, big bang The young universe began to expand rapidly due to an invisible force known as the “plasma broth.” dark energy. As the universe grew, ordinary matter that interacted with light congealed around invisible clumps of matter. dark matter Create your first galaxy connected in the vast cosmic web. Cosmologists currently believe that ordinary matter, dark matter, and dark energy make up about 5%, 25%, and 70% of the universe, respectively.
However, this situation is becoming more problematic. To test models, astronomers often compare the past and present universe. Their past measurements were obtained from the Cosmic Microwave Background (CMB), the universe’s first static bubble of light that left its source 380,000 years after the Big Bang (recombination of atoms). Masu.
However, the Hubble constant (a value that tracks the rate of expansion of the universe) predicted from the CMB did not match calculations derived from objects in the modern universe. This contradiction created a cosmological crisis known as the Hubble tension.
The new contradiction about the lumpiness of the universe centers around a number called S8, which measures how much matter is clumped together, or clumped, throughout the universe. After using the Planck satellite to study the cosmic microwave background radiation (CMB), astronomers previously incorporated the data into the standard model of cosmology. The predicted value for S8 was 0.83.
This conflicts with the S8’s new measurements using Japanese standards. subaru telescope, studied how much light is distorted by the presence of matter in galaxies. The researchers took that result and calculated a smaller value of 0.77 for S8. This new result was replicated by two of his other collaborations that use gravitational lenses to map matter in the universe. dark energy research And that kilometer survey — Individual anomalous results are less likely to occur.
“We are now in the community recognizing that there is a real discrepancy between measurements of cohesion in the early Universe (measured from the CMB) and measurements of cohesion at the age of galaxies, i.e. ‘only’ 9 billion years ago. We have confirmed that it is increasing within the country.” Arun Kannawadisaid an associate researcher at Princeton University who was involved in the analysis in a statement.
This problem represents another gaping hole in our understanding of the universe, but cosmologists don’t yet have a good way to fill it. It’s possible that cosmologists are wrong about the amount of dark matter in the universe or how dark matter clumps together. Perhaps dark energy has changed throughout the life of the universe. This is an explanation that resolves both the S8 and Hubble tensions by tweaking the standard model of cosmology.
Or, perhaps most interestingly, it could mean that the standard model is broken and requires a complete replacement. It will take more powerful telescopes and more precise measurements before scientists will know for sure. Two such candidates are the Vera C. Rubin Observatory in Chile and the Nancy Grace Roman Space Telescope, which are scheduled to become operational in 2025 and 2027, respectively.