A couple of years ago, a team of scientists observed a series of mysterious particles in Antarctica that were postulated as possible evidence of a parallel world formed in the Big Bang.
Now, new research suggests precisely the existence of an invisible “mirror world” of particles, which interacts with our world through gravity and could solve the problem of the Hubble constant.
What is the Hubble constant?
The Hubble constant is the expansion rate of the universe today. According to the standard model of cosmology, predictions for this rate are significantly slower than those found by more precise local measurements. What is this discrepancy about? Why doesn’t the expansion of our universe seem as steady as researchers expected? The two figures are different and multiple tests have made it clear that this is not a measurement error. While it remains a possibility, it is important to note that the discrepancy has become increasingly significant as higher quality data have been included in the analyses.
So far, there is no explanation for why this is so, and the answer is likely to require a fundamental rethinking of our understanding of the cosmos.
Cosmologists have been trying for many years to resolve this difference by changing our current cosmological model. But everything has to remain in balance with factors as crucial as the cosmic microwave background.
A solution to the problem?
A team of scientists claims to have found a new mathematical property of cosmological models that could solve this problem, since it allows the universe to expand more rapidly without changing the model in ways that would be problematic elsewhere. The discovery suggests that there could be a universe, very similar to our own, that remains almost completely invisible. But it can be seen in the evidence for the gravitational impact on our own, say the authors, who publish their work in the journal Physical Review Letters.
“This may seem crazy at first glance, but these mirror worlds have a great physics literature in a completely different context, as they can help solve an important problem in particle physics,” comments Francis-Yan Cyr-Racine, assistant professor in the Department of Physics and Astronomy at the University of New Mexico, and one of the authors of the research. “Our work allows us to link, for the first time, this great literature with a major problem in cosmology.”
Referencia: Francis-Yan Cyr-Racine, Fei Ge, Lloyd Knox. Symmetry of Cosmological Observables, a Mirror World Dark Sector, and the Hubble Constant. Physical Review Letters, 2022; 128 (20) DOI: 10.1103/PhysRevLett.128.201301