According to a new study, our Universe may have an unusual shape. Scientists suggest that it could be asymmetric, meaning it is not the same in all directions.
The existing standard cosmological model, or Lambda-CDM model, which describes the evolution and structure of the Universe, is based on the assumption that it is isotropic, meaning it looks the same in all directions and is homogeneous on large scales. However, several contradictions, or discrepancies in the data, call this idea into question. Astrophysicists presented a study dedicated to one of the most significant contradictions found in the Universe, known as the cosmic dipole anomaly. The scientists concluded that it poses a serious problem for the standard cosmological model. The study was published in the journal Reviews of Modern Physics, reports ScienceAlert.
What is the cosmic dipole anomaly, and why does it pose a problem for describing space? We need to start with the relic radiation that remains from the Big Bang. This radiation is extremely homogeneous throughout the cosmos.
Therefore, astrophysicists are confident in the model of the Universe, using the most symmetrical description of spacetime in Einstein's theory of general relativity. This symmetrical description of the Universe, where it looks the same everywhere and in all directions, is known as the Friedmann–Lemaître–Robertson–Walker metric. This significantly simplifies the solution of Einstein's equations and serves as the foundation for the standard cosmological model.
However, there are several important anomalies, including the Hubble problem. It consists of the fact that the value of the expansion rate of the Universe in its early history does not match the value in the more modern, and therefore closer, cosmos. The cosmic dipole anomaly is a less well-known contradiction, but it has even greater significance for understanding the Universe, according to astrophysicists.
When scientists found that the relic radiation is symmetric on large scales, they discovered that there are variations in this radiation. One of the most significant is called the dipole anisotropy of the relic radiation. This is the largest temperature difference in the relic radiation, where one part of the cosmos appears hotter, while the other is colder.
There is also a hypothesis that a similar variation, or dipole anisotropy, is observed in the distribution of matter throughout the cosmos. If the assumption of a symmetric Universe is correct, then this variation in the distribution of matter should be directly determined by the variation in relic radiation.
Consistency between variations in relic radiation and in matter would confirm the correctness of the standard cosmological model. Discrepancies would directly call it into question. However, data to verify this has only recently become available. The study shows that the variation in matter does not correspond to the variation in relic radiation.
Thus, the cosmic dipole anomaly becomes a serious problem for the standard cosmological model. This means that the Universe may be asymmetric, and therefore, a new model of the evolution and structure of the cosmos may need to be created. Astrophysicists believe that additional data is necessary to verify the findings, which they hope to obtain in the near future. According to the scientists, if their conclusions are correct, it could completely disrupt our understanding of the Universe.
