What is the vacuum of space?
In astronomy, the void in space is a space in which the density of matter is very small compared to the rest of the universe. Below is everything you need to know. Many people believe that in those regions of the universe where there are no stars, planets or galaxies, there is nothing. In reality, this is not at all the case. When we talk about vacuum, in astronomy we mean that large section of space in which the density of matter is very small, but not equal to zero. Less than one tenth of the average density: this is the reference value for scientists hunting for cosmic voids. And this is true: there are regions in our Universe where we find very, very few isolated galaxies. We owe the discovery of these voids to scientists Stephen Gregory and Laird Thompson of the Kitt Peak Observatory in 1978. How Cosmic Void Formed The image above is a large-scale representation of the distribution of matter in the universe. The blue threads are matter (both ordinary and dark matter, but mostly the latter fills the universe). The empty spaces between the threads are called space voids. Threads containing clusters and superclusters of galaxies, held together by dark matter, delimit these voids. Vacuums are thought to be between 11 and 150 megaparsecs in size, and especially large vacuums are called supervacuums. According to scientists, the voids were formed as a result of massive collapses of compressed baryonic matter after the Big Bang. The regions with the highest density collapsed faster under the influence of gravity, resulting in a structure similar to a kind of cosmic web, with voids and threads of galaxies, which we observe today. Among other things, there seems to be a correlation between voids and cosmic background radiation. This is a consequence of the so-called gravitational redshift and the Sachs-Wolf effect: colder regions will be closely connected to these voids, and filaments will appear in warmer regions. And since the Sachs-Wolf effect only makes sense if the universe is dominated by radiation and dark energy, the existence of voids is further proof of the existence of this mysterious force.
Source: New-Science.ru https://new-science.ru/chto-takoe-kosmicheskij-vakuum/