The fact that our Universe is expanding was discovered almost a hundred years ago, but how exactly this happens, scientists realized only in the 90s of the last century, when powerful telescopes (including orbital ones) appeared and the era of exact cosmo.
International Journal of Modern Physics has published an article by the IKBFU Physics and Mathematics Institute Artyom Astashenok and the Institute’s MA student Alexander Teplyakov. The article refers to the issue of the “Dark Energy” and an assumption is made that the Universe has borders.
Artyom Astashenok told:
“The fact that our Universe is expanding was discovered almost a hundred years ago, but how exactly this happens, scientists realized only in the 90s of the last century, when powerful telescopes (including orbital ones) appeared and the era of exact cosmology began. In the course of observations and analysis of the data obtained, it turned out that the Universe is not just expanding, but expanding with acceleration, which began three to four billion years after the birth of the Universe.”
For a long time, it was believed that space is filled with ordinary matter — stars, planets, asteroids, comets and highly rarefied intergalactic gas. But, if this is so, then accelerated expansion is contrary to the law of gravity, which says that bodies are attracted to each other. Gravitational forces tend to slow down the expansion of the universe, but cannot accelerate it.
Artyom Astashenok says:
“And then the idea was born that the Universe is filled for the most part not with ordinary matter, but with some “dark energy,” which has special properties. No one knows what is it and how it works, so it named “Dark Energy” as something unknown. And 70% of the Universe consists of this Energy.”
There are many theories of what the “Dark Energy” is, and the IKBFU scientists presented their own theory.
“The so-called Casimir effect (named after the Dutch physicist Hendrik Casimir), which consists in the fact that two metal plates placed in a vacuum are attracted to each other, has long been known. It would seem that this cannot be, because there is nothing in the vacuum. But in fact, according to quantum theory, particles constantly appear and disappear there, and as a result of their interaction with plates, which indicate certain boundaries of space (which is extremely important), a very small attraction occurs. And there is an idea according to this, approximately the same thing happens in space. Only this leads, on the contrary, to additional repulsion, which accelerates the expansion of the Universe. That is, there is essentially no “Dark Energy,” but there is a manifestation of the boundaries of the Universe. This, of course, does not mean that it ends somewhere, but some kind of complex topology can take place. You can draw an analogy with the Earth. After all, it also has no boundaries, but it is finite. The difference between the Earth and the Universe is that in the first case we are dealing with two-dimensional space, and in the second — with three-dimensional.”
The published article, which, as explained by Artem Astashenok, develops the ideas presented in the thesis of Alexander Teplyakov, presents a mathematically sound model of the universe in which additional repulsion occurs, and where there is no contradiction between the fact that the expansion of the Universe accelerates and the law of universal gravitation.
Reference: “Some models of holographic dark energy on the Randall–Sundrum brane and observational data” by A. V. Astashenok and A. S. Tepliakov, 2 December 2019, International Journal of Modern Physics D.