Researchers claim that evidence found against the `` flat cosmic theory '' that the universe does not contract


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Since the universe was born about 13 billion years ago, it is said that it has continued to expand. In recent years, the `` flat universe '' theory that the expansion of the universe will not shrink in the future is thought to be powerful by scientists, but the research team that analyzed the new data, `` the universe is flat Rather, a theory that 'it is likely to be a closed universe' was announced.

Planck evidence for a closed Universe and a possible crisis for cosmology | Nature Astronomy
https://www.nature.com/articles/s41550-019-0906-9

Everything We Know About the Shape of the Universe Might Be Wrong | Live Science
https://www.livescience.com/universe-may-be-curved.html


Various theories have been proposed as to whether the universe, which has been expanding since the Big Bang, will continue to expand, or will eventually contract. Regarding the expansion pattern of the universe, there are three cosmic patterns: “closed universe”, “flat universe”, and “open universe” based on the idea of the “curvature of the universe” that indicates the bending of spacetime.

When the mass contained in the whole universe exceeds a certain critical amount, the universe that has continued to expand will turn into contraction due to its own gravity. In this case, suppose that the curvature of the universe is +, the state where the mass and the critical amount are balanced is 'zero curvature of the universe', and the state where the mass is below the critical amount is 'the curvature of the universe is-' I call. If the curvature of the universe is +, the universe will eventually become a “closed universe” that will begin to contract, and if the curvature of the universe is zero, the “flat universe” where expansion will stop in an infinite future, and the curvature of the universe is- It is said that it will become an “open universe” where expansion continues forever.

This is an easy-to-understand illustration of the differences on the website of the National Science Museum, which explains the open and closed universes. In the open universe, the universe gradually expands from the big bang at the left end, but in a closed universe, when it exceeds a certain level, it begins to contract and eventually reaches the end of the universe called the big crunch .


Although it is difficult to accurately measure the mass of the universe, scientists have regarded the theory that the universe is flat from recent observations. However, Eleonora Di Valentino from the University of Manchester , Alessandro Melchiorri from the University of Roma La Sapienza , and Joseph Silk from Johns Hopkins University said, “Evidence that the universe is closed from new observations Has been found and is in debate.

The proof of the closed universe by the research team is detailed mapping data of cosmic microwave background radiation released by the European Space Agency (ESA) in 2018 as 'Planck 2018 Results'. Cosmic microwave background radiation is a microwave observed almost isotropically from all directions on the celestial sphere, and is said to be evidence of the Big Bang theory.

This cosmic microwave background radiation is not only thought to have occurred immediately after the Big Bang, but has spread throughout the universe, and is considered one of the most important data on the history and behavior of the universe. According to the latest observational data from ESA, the gravitational lensing effect in cosmic microwave background radiation seems to be greater than expected, saying, “Why gravity not explained by existing physics is bending cosmic microwave background radiation? 'The research team thought.

Therefore, as a result of exploring a method to explain the extra gravitational lens effect, the research team found that it was possible to explain this phenomenon in a closed universe rather than a flat universe. “This can be explained by general relativity , so it is a physical interpretation rather than giving a new parameter (to explain an unknown phenomenon),” Melchiorri says.

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Melchiorri admits that the theory published by his research team is not definitive because the results are not statistically reliable enough. He also explains that if the universe is not flat, many mechanisms related to the universe will need to be re-adjusted, causing many problems.

“I don't want to say that I believe in a closed universe. I'm a little more neutral. Let's wait for what the current data and the newer data show. 'We believe we need to be careful and try to find the cause of the contradiction,' Melchiorri said.

by Jacub Gomez

in Science, Posted by log1h_ik