Most of modern-time astrophysicists agree that the Universe contains a notable amount of so-called dark matter. But how much of this matter, to be exact? There are even several cosmological models which were created with aim to explain the presence of dark matter, although most of them rely only on ‘heavyweight’ theoretical assumptions and lack a real evidence-based substantiation. However, some progress in this area is being bade by comparing theory to astronomical observational data.

Brazilian astrophysicists R. C. Freitas, S. V. B. Goncalves and A. M. Oliveira used such comparisons to determine some of the cosmological parameters of our Universe by analyzing famous gravitational lensing effect. The basic idea is that the strength of gravitation-induced space-time distortion should be proportional to the distribution of matter in the observed area of the universe, and, therefore, should reflect the amount of dark matter which could be present in the same cosmic region.

Scientists compared six different most promising existing cosmological models: standard cold dark matter (CDM) model, ΛCDM model, Bose-Einstein condensate dark matter model, Chaplygin gas model, the viscous fluid cosmological model and the holographic dark energy model.

The ‘standard’ CMD represents probably the most simple scenario of our Universe, according to which ~5% of it is made up of atoms, ~23% is composed of cold dark matter (CDM) and ~72% consists of hypothetical dark energy. Interestingly enough, according to the results presented in the scientific paper at arXiv.org, this model is not very realistic since it doesn’t match the observational data very well, although authors do not assert that this model could be incorrect.

The investigated models use significantly different parameters, and the Brazilian team admitted that it is quite difficult to make a precise comparison regarding the magnitude of gravitational lensing effect. In any case, it is apparent that different cosmological models yield different results when estimating locations and effects of particular gravitational lenses, especially when varying parameters on which the cosmological models are build upon.

Authors also admit, that this analysis is only a preliminary study which lacks precision due to inherent inconsistency between parameters of different cosmological models. In their work, scientists propose a further work to calculate the theoretical predictions of gravitational lenses in our visible part of the Universe and to compare them with the results of available astronomical observations. According to the authors, such analysis could restrict the range for variability of parameters used in different cosmological models, therefore permitting a more precise theoretical analysis of gravitational lensing effect.

By Alius Noreika, source: Technology.org