Physicists presented new arguments in favor of the fact that the universe will cease to exist after 22 billion years as a result of the so-called Big Rip. The results of their research published authors in the journal Physical Review D.
In their study, the researchers used a new approach to the so-called cosmological bulk viscosity. As the application of thermodynamics and fluid dynamics to equations of general relativity, which describes the evolution of the universe, the cosmological contribution volume (or second) viscosity in the equation of state of the universe is described by its energy balance is compared with the contribution of shear viscosity, decisive.
In contrast to the shear viscosity, is responsible for the dissipation (scattering) energy in the medium as a result of movement and the mutual friction of its layers to each other, there is the bulk viscosity in compressible liquids and gases, and even at the level of classical hydrodynamics little studied . If the universe considered as a space filled with relativistic (moving at near-light speed) fluid, such a description makes it possible to draw conclusions about its development in the future, however, it leads to superluminal movement contrary to modern physics.
When a homogeneous (properties are not dependent on location) and isotropic (properties do not depend on the direction of) the expansion of the universe, which is observed at present, the equation of state of the universe is commonly defined as the ratio of dark energy pressure to its density, expressed as ( in a special system units) by the dimensionless parameter w. Its value determines the evolution of the universe.
At present, it is unknown what this value. If w is less than minus one, is conjecture Big Rip. According to her, the universe will cease to exist as a result of accelerated expansion, which will lead to the disintegration of matter. In this model, the observer, who turned out in such ceases to exist the world would notice the decay of matter up to the extent of applicability of the laws of modern elementary particle physics, reports «to Lenta.ru» .
In their study, scientists were able to circumvent the problem of superluminal motion of matter in the description of the universe as a compressible liquid-filled space, modifying the approach proposed in 1950 by the French mathematician Andre Lichnerowicz. According to the scientists, their study allows to review the possible role of dark energy, which is introduced to explain the observed
According to scientists, in the process bulk viscosity may play an important role, and some effects that are described introduction of dark energy can be explained by the influence of bulk viscosity. Most theories of dark energy, scientists say, the influence of bulk viscosity is not considered. Information on the latter, according to researchers, can serve as a limitation on the data on dark energy.
If the previous value of w, a smaller negative one, determine the threshold at which there is a big gap, but now, according to scientists, there is no need for a threshold and allows a natural development of the universe to w, at minus one. According to scientists, they obtained a theoretical model can be tested numerically using supercomputers. The resulting information after that scientists are going to compare with observations.
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