The new data shows that they can explain the fundamental divergence in measuring the rate of expansion of the universe.
In a new paper, the main participants in this dilemma reviewed the available information and concluded that the best observations may indicate that we have gained the standard picture of how the universe grows over time.
Scientists know that the universe is expanding, but for ten years they have disagreed with the speed of this process. Data using the cosmic microwave background (CMB) (light left shortly after the Big Bang) show that the Hubble constant to measure this expansion should be about 46,200 miles per hour per million light years, or 67.4 kilometers. per second. The unit of the cosmologist is per million parsecs. (One megaparsec equals 3.26 million light years.)
Related: The Big Bang to the Present: A Snapshot of Our Universe Over Time
However, star-trained telescopes in the nearby universe have proposed 50,400 miles per million light years Measured value of the Hubble constant per hour (73.4 km / sec / Mpc). The two numbers are not different, but each number is very precise and cannot be coordinated with each other.
The tension between these two numbers has always been a headache for researchers, some people believe that this difference forces them to flip their preferred cosmological model, which explains how huge cosmic structures like galaxy clusters appear from the dawn and the time of evolution. Researchers may want to know that new physics beyond what we currently know can be used to bridge this gap.
“I think this is a very interesting question: ‘Is there new physics beyond the standard cosmological model?” University of Chicago cosmologist Wendy Friedman told Live Science.
Friedman has spent most of his career observing so-called Cepheid variables. These regularly pulsating stars have a relationship between the period of light fluctuations and their inherent brightness, which means how bright they will be if we stand next to them. By understanding the intrinsic brightness and luminosity of Cepheid variable stars seen from Earth, astronomers can calculate the distance between them and us and then measure the expansion rate of the universe at that point in space. The data from the variable star Cepheid
is one of the keys to the higher value of the Hubble constant, but Friedman and his collaborators have always doubted whether they made systematic errors in their observations. They have long been looking for independent ways to confirm or question their results.
A few years ago, she and her colleagues discovered a path under the huge light of the red star. These celestial bodies represent the last stages of the life of stars similar in mass to the sun, reaching a certain maximum brightness at some point in their evolution. Like Cepheid variable stars, astronomers can estimate their distance well by observing how dark they look from Earth.
In 2019, Friedman and his team provided the Hubble constant with a number that falls exactly between the other two measurements: 47,300 miles per hour per million light years (69.8 km / sec / Mpc). The result was calibrated using the giant red star in the Large Magellanic Cloud, which is a dwarf galaxy orbiting the Milky Way, and its distance from us is relatively safe.
Since then, the researchers have added more data points and calibrated the distances of the other three galaxies and the giant red stars in the space regions, thus improving the precision of their constant Hubble measurements. These findings are basically the same as those for the intermediate estimates, which appeared in a paper published in the preprint arXiv database on June 29, which was accepted for publication by the Astrophysical Journal.
“It landed in the same place, just under 70 [km / s / Mpc], and the uncertainty was slightly over 2%,” Friedman said of Hubble’s new constant estimate of the red giant. “If we compare these results with CMB, we will not say that there is a problem. These latest measurements of the
red giant indicate that there may be systematic errors in observing Cepheid variable stars, Friedman said. He added that blocking dust and backlight from the universe are some possible culprits, although it will take time to really find out if this is the case.
“I’m very impressed with the work and the details,” Simon Birrer, a cosmologist at Stanford University in California, told Live Science who was not involved in the research. He added that this document highlights the specific benefits of observations of the red giant.
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But Birrer, he’s a researcher Team members on how large galaxies distorted light They provided another independent measurement of the Hubble constant, and I don’t think the legend is over yet. “Is this the beginning of the end of the tension? We are still working hard,” he said.
Astronomers now provide many different estimates of the expansion of the universe, some of which agree and some of which disagree. Birrer said each team is trying to provide the best possible accuracy, but it is not yet clear which ones might contain the final answer.
Friedman agreed, saying that she and her colleagues had recently been approved to use the upcoming James Webb Space Telescope to observe Cepheid variables and red giant stars. These observations should help clear up some remaining uncertainties from the system and hopefully get closer to the true value of the Hubble constant.

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