The expansion of the universe may be slower than previously thought
The web of the universe was compiled over a long period of time. Under the control of gravity, they gradually coalesced from what formed billions of years ago during the Big Bang. The universe is constantly growing, and as slow as this growth may seem to us, physicists Nhat Minh Nguyen, Dragan Hutterer, and Yue Win of the University of Michigan want to slow this process even further.
The modification they proposed could resolve the major contradiction that arose during observations of the expansion of outer space in the model that currently best describes our universe. For some reason, nothing is growing, squeezing itself into the gaps between galaxies to gently expand the structure of the universe at an ever-accelerating rate. Since we don’t know what’s behind this mysterious expansion, we just call it dark energy.
“If gravity acts as an amplifier that amplifies perturbations of matter so that the structure of the universe grows, then dark energy acts as a damper that dampens these perturbations and slows their growth,” said Nguyen, the study’s lead author. “By looking at how cosmic structure assembles and grows, we can try to understand the nature of gravity and dark energy.”
Growth is soothing
The exact rate of expansion, known as the Hubble constant (H0), is not at all clear. If we measure how certain types of exploding stars are pulled so far away, we can get an acceleration of 74 kilometers per second per million parsecs. Using the cosmic microwave background (CMB), the “light echo” of rectangular radiation still reflected after the Big Bang, H0 approaches 67 kilometers per second, the researchers wrote. Science Alert.
This may not seem like a big difference, but the difference persists through enough testing that it is no longer treated as a negligible error. Nguyen, Hutterer, and Winn reconsider the flat cosmology model ΛCDM as a possible source of false assumptions. If, for some reason, the process of evolution of the universe deviates from that predicted by the consensus model and prevents the growth of the large-scale structure of the universe, then the tension between different scales of the universe’s accelerating expansion will disappear.
The researchers used a combination of measurements of cosmic web ripples, gravitational lensing events, and details of the cosmic microwave background to arrive at a statistically convincing conclusion: that the cosmic web is growing more slowly than predicted by the ΛCDM cosmology model. “The difference between the growth rates we are likely to discover becomes more pronounced the closer we get to the present,” Nguyen says. “Individually and together, these different investigations point to growth inhibition. Either we have overlooked some methodological errors in the individual investigations, or new and late theories of physics are missing from our standard model.”
It took the universe 13.7 billion years to reach its present state. It will take a few years to develop the theory accurately.
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