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Is the universe expanding faster than scientists thought?

Based on numerous observations of stars andof galaxies, scientists began to notice that the universe is scattering faster than the most accurate models of the cosmos show. Evidence of this has accumulated over the years, with the result that some scientists have called this process an impending crisis in cosmology. The latest data that a group of researchers managed to collect using the Hubble Space Telescope suggests that there can be no mistake, the universe is really scattering faster. The puzzle is named “Hubble stress” after astronomer Edwin Hubble. In 1929, he noticed that the farther a galaxy is from us, the faster it moves away. However, not all scientists agree with these findings, and still argue that the “Hubble tension” is just an artifact. But what are the pros and cons?

Latest research shows the universe is expanding at an accelerating rate

Content

  • 1 What is the Hubble voltage and how the expansion rate of the universe was calculated
  • 2 Space microwaves and remote ladder
  • 3 Accounting for errors and variations in measuring the rate of expansion of the Universe
  • 4 Is the Hubble voltage a calculation error?
  • 5 An explosion of dark energy and a rejuvenated universe

What is the Hubble voltage and how the expansion rate of the universe was calculated

Researchers tried to measure the current speedexpansion of the Universe in two main ways - by measuring the distances to nearby stars and by mapping the faint glow associated with the young Universe. The study also revealed some key cosmic ingredients such as dark energy, a mysterious force believed to be driving the accelerating expansion of the universe.

These two methods show different results.relative to the current rate of expansion of the Universe. The discrepancy is approximately 8 percent. This difference may seem insignificant, but if it really exists, then the universe began to expand faster than at the beginning of its existence.

Most of the data scientists use in their calculations, obtained from the Hubble telescope

Several studies published by TheAstrophysical Journal, certain types of stars and stellar explosions are used to measure the distance between us and nearby galaxies. The dataset includes observations of 42 different stellar explosions, more than double the scale of previous analyzes of this kind. According to the results, the inconsistency between their new analysis and measurements from the early cosmos has reached five sigma, a statistical threshold used in particle physics to confirm the existence of new particles.

Space Microwaves and Remote Ladder

One way to get a Hubble constant(the rate of expansion of the universe) is based on the cosmic microwave background (CMB), a faint glow that formed when the universe was only 380,000 years old. Telescopes such as the European Space Agency's Planck Observatory have measured the CMB, providing a detailed snapshot of how matter and energy were distributed in the early universe, as well as the physics that controlled them.

Using a model that with amazing successPredicting many properties of the universe, known as the Cold Dark Matter Lambda model, cosmologists can mathematically calculate the evolution of the young universe and predict what today's Hubble constant should be. According to this method, the universe should be expanding at a speed of about 67.36 kilometers per second per megaparsec.

One megaparsec equals 3.26 million light years.

Scientists use data from stars and galaxies to calculate the Hubble constant

Other teams measure the Hubble constant by lookingto the “local” universe, that is, more modern stars and galaxies that are relatively close to us. This version of the calculation requires two types of data: how quickly the galaxy is moving away from us and how far this galaxy is. This method requires astronomers to develop a so-called space distance ladder.

The ladder of cosmic distances of the newThe study, compiled by the SHoES research group, begins by measuring the distances between us and certain types of stars, called Cepheid variables. To expand the ladder even further, astronomers added rungs based on stellar explosions called Type 1a supernovae.

Studying the galaxies in which there are bothCepheids and type 1a supernovae, astronomers can establish a relationship between the brightness of supernovae and the distance to them. Because Type 1a supernovae are much brighter than Cepheids, they can be seen at much greater distances, allowing astronomers to extend their measurements to galaxies deeper in space.

There can be errors in the calculations of the Hubble constant, since it is difficult to obtain accurate information about Supernovae and other space objects that are located at a great distance from the Earth.

Accounting for errors and variations in measuring the rate of expansion of the Universe

The problem with calculating the Hubble constant isis that it is extremely difficult to accurately measure the data of all stars and supernovae. Technically speaking, not all Cepheids and Type 1a supernovae look the same. Some of them may have different compositions, different colors, or different types of host galaxies. Astronomers have spent many years figuring out how to explain all this variability. Nevertheless, it is extremely difficult to say with certainty that an error has not crept in in one dimension or another.

To solve these problems, researchA group called Pantheon + has exhaustively analyzed over 1,700 Type 1a supernova observations collected since 1981. The analysis included a quantification of all known uncertainties and sources of bias.

The Hubble constant, obtained taking into account possible errors, confirmed the acceleration of the expansion of the Universe

After exhaustive cross-validationFor factors that could affect Cepheid observations, the team gave the most accurate estimate for the Hubble constant at 73.04 kilometers per second per megaparsec, plus or minus 1.04. This is about 8 percent higher than the value derived from CMB measurements by the Planck Observatory.

The team has also made every effort totest outside scientists' ideas about why her estimate of the Hubble constant is higher than Planck's. In total, the researchers looked at 67 analyzes, many of which exacerbated the Hubble tension puzzle.

Is the Hubble voltage a calculation error?

Wendy Friedman, University of Chicago Scientistworked on an estimate that is not based on pulsating stars. Instead, she used a specific group of red giant stars that act like light bulbs of known wattage. Based on these alternative objects with known internal brightness, the Hubble constant was 69.8 km / s per megaparsec.

Scientist Wendy Friedman independently calculated the Hubble constant using "reliable" sources

Despite the team's meticulous work, Friedmansays that undetected errors can still affect analysis, possibly creating an illusory tension. Some sources of uncertainty are inevitable, she said. There are only three galaxies close enough to the Milky Way that we can measure distances directly.

The Pantheon + and SH0ES teams have carefully studiedthe results of Friedman and other researchers. According to their work, the inclusion of additional stars, which Friedman used, slightly lowers the estimate of the Hubble constant, but does not relieve tension. And if the Hubble tension really reflects our physical reality, as scientists argue, then explaining it will probably need to add another item to our list of fundamental components of the universe.

An explosion of dark energy and a rejuvenated universe

According to one theory, after about 50 thousandyears after the Big Bang, there was a short burst of dark energy. In principle, a short burst of additional dark energy could alter the expansion rate of the early universe enough to create a Hubble stress without violating the standard model of cosmology.

The James Webb Telescope will probably help get more accurate information on the rate of expansion of the Universe.

But, according to cosmologists, the age of the universewill fall from the current 13.8 billion years to about 13 billion years. At this point, there is no clear evidence of early dark energy. Although there are still some hints. In September, the Atacama Cosmological Telescope, an institution in Chile that measures the cosmic microwave background, said the model including early dark energy matched their data better than the standard cosmological model. True, there is a theory according to which dark matter, on the contrary, slowed down the expansion of the universe.

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Obviously, to solve the Hubble voltageadditional, more accurate observations will be required. Perhaps the final point in the dispute about the rate of expansion of the universe will be put by the James Webb Telescope, which will double-check the measurements made earlier by the Hubble Telescope.