Research

The rate of expansion of the universe was higher than expected.

The results of the new American studyastronomers, published in the Astrophysical Journal Letters, indicate that the universe is expanding about 10 percent faster than expected based on observations from the Planck space telescope, which may suggest a need for a new space phenomena occurring in it, reports Space.com. The preprint of the work can be freely found in the online repository of scientific articles arXiv.org.

The probability that this discrepancy is a mere coincidence has been reduced from one three thousandth to one thousandth, scientists note.

"This discrepancy has reached a point when to callit can no longer be accidental, ”commented Adam Riess, a professor of physics and astronomy at Johns Hopkins University in Baltimore (USA), who studies the study.

“This is not what we expected,” addsRiesz, who in 2011 (together with other physicists Brian Schmidt and Saul Perlmutter) received the Nobel Prize in Physics for proving the accelerated expansion of the Universe and the development of ultra-precise methods for measuring distances.

Scientists still cannot understand what exactlyincreases the rate of expansion of the universe, but many astronomers suggest that the culprit is a mysterious repulsive force called dark energy.

This illustration shows the three mainsteps that astronomers use to calculate the rate of expansion of the universe over time. This value is called the Hubble Permanent. All steps include the construction of the steps of the “space distance ladder”, starting with the measurement of exact distances to the nearest galaxies, and then moving farther and farther towards the galaxies. This “ladder” is a series of measurements of various types of astronomical objects with their luminosity indices, which can be used to calculate distances.

In the new study, Riess with colleaguesused data from the Hubble Space Telescope, containing information about observations of 70 Cepheids (stars with variable brightness) in the Large Magellanic Cloud, a galaxy adjacent to our Milky Way. For astronomers, Cepheids are a kind of beacon, thanks to the dependence period-luminosity, Cepheids are used as luminosity standards when determining distances to distant objects.

Another “guide” for speed calculationsextensions of the Universe may be type Ia supernovae, whose light is stretched as the space it overcomes expands. However, the main problem lies in determining the exact distance to these stars. Studying and observing precisely these stars allowed Riss, Schmidt and Permutter to receive the Nobel Prize.

Riesz with the team also included in their calculations,obtained during the Araucaria project, in which scientists from the USA, Europe and Chile made observations on the binary stellar systems of the Large Magellanic Cloud galaxy, noting the “eclipses” of stars that occurred when one star passed before its neighbor. This work provided Riesz and his colleagues with additional information about the distances to the stars, providing scientists with assistance in understanding the internal brightness of Cepheids.

Armed with data, the researchers usedthem to calculate the current rate of expansion of the universe - the value, which is called the Hubble constant. It received its name in honor of the famous American astronomer Edwin Hubble in the 20s of the last century. As a result, researchers received a new Hubble constant of 74.03 kilometers per second per megaparsec (1 megaparsec is equal to about 3.26 million light years), which is more than the constant derived from observations of the background radiation and equal to 67 kilometers per second per megaparsec. This means that the speed of separation of galaxies from us increases by almost 74 kilometers per second, and not by 67, as it was considered before. The hitch is that the previous value is taken into account in all our models, which describe both the age of the Universe and its composition, as well as the fundamental laws of physics.

According to the Riesz team, the maximum errorTheir calculations can be as low as 1.9 percent - the lowest at the moment. For example, in the 2001 surveys, the calculation error was about 10 percent, while the data for 2009 indicated an error of 5 percent.

New estimate of the expansion rate of the universecontrary to the value of the Hubble constant, obtained by the Planck telescope of the European Space Agency, which conducted studies of cosmic background radiation left after the Big Bang, which according to the most popular scientific opinion, spawned our Universe about 13.82 billion years ago.

“These are not just two inconsistent experiments. We measure something fundamentally different. In the first case, we are talking about measuring how quickly the Universe visible today is expanding, and in the second, it is a prediction based on the physics of the early Universe and data on how fast it should expand. If these values ​​do not match, there is a very high probability that we are missing something in the cosmological model that connects two epochs, ”concludes Riess.

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