What is the universe? The definition of this commonly used concept is not so simple. If formulated extremely succinctly: this is all that exists. However, a similar answer to the question of what the Universe (definition) is, does not really explain anything. Therefore, we dwell on it in more detail.
Two options
You can start with the fact that the concept of “Universe” is fundamental in two of the largest sciences of all time: philosophy and astronomy. In general, similar meanings of a word have a fundamental difference. In the first case, the universe is understood as a speculative structure, in the second - material. Strictly speaking, a detailed but clear definition of “the Universe is ...” is absent both in philosophy and in astronomy. Moreover, each study, physical or mental, as an object has an element of the universe.
Various sciences are engaged in observing different parts of the whole, designated as the Universe. Cosmology and astronomy are trying to cover it all. It is from the point of view of these sciences that this article will give an answer to the question of what the Universe is, the definition of a concept as a combination of space and time, existing forms of matter, and also the laws that govern them.
In the depths of centuries
If we turn to history, the first hypotheses on this topic arose in Ancient Egypt and Mesopotamia. Representations that can be called scientific appeared in the period of antiquity. The prevailing definition was then: The Universe is an eternally existing structure, in the center of which is the Earth. Around her in orbits, according to the ideas of Aristotle, Ptolemy and Pythagoras, planets revolve, including the Sun. Farther than other objects from the Earth are stars, which also revolve around the center of the Universe.
Such a picture of the world underwent a serious revision only after the appearance of the works of Copernicus and Newton. A heliocentric model has arisen. The discoveries of galaxies and other cosmic objects and phenomena significantly complemented the scientists' ideas about the Universe. Today, the study of distant objects, the progressive development of the methods of astronomy and astronautics have led to the emergence of a more or less clear understanding of the universe. However, daily incoming data, which often do not fit into existing theories, make it possible to consider any definition of the word "Universe" non-final.
Structure
The macrostructure of the Universe can be described as a space with a sponge-like structure. The walls of this structure are formed by a huge number of galaxies. The distance between the neighboring ones in most cases is approximately a million light-years.
The main elements of galaxies are stars, constantly revolving around a single center. The main substance that makes up stars is hydrogen. Among other elements, it is fundamental in our universe.
Was there a beginning?
The age of all things is not such a simple question as it might seem. In order to answer it, for a start it is necessary to accept the fact that the Universe did not exist forever. For a world accustomed to living according to religious canons, it was hard to try on the theory of a timeless universe. Also, after a while, the scientific community was seriously accustomed to the idea that a certain event was preceded by the appearance of the world - it too reminded of a biblical creation. However, weighty arguments made the big bang theory, which everyone today has heard, leading in cosmology. It is in it that the moment of the beginning of the Universe is described. According to scientists, it was 13.7 billion years ago.
Big explosion
The prevailing theory today suggests that the moment of the appearance of the Universe was accompanied by a big explosion, and its origin is not described in theory. A tremendous amount of energy was compressed to incredibly small sizes and began to expand. At the same time, the substance of the Universe was heated to enormous temperatures. Under such conditions, the first elementary particles began to form. One of the proofs of the theory is relict background, radiation, the source of which was a big explosion. No hypotheses suggesting the eternal existence of the universe can explain it.
Future
The universe is expanding so far. Existing models for describing this process do not converge basically: in what the future of the whole system will be. There are two possible options:
- The universe will expand indefinitely.
- At some point, the reverse process will begin, and everything will end with a big compression.
The list of likely finale options also includes the theoretically possible great freezing, thermal death, and a large gap in the universe.
Space curvature
Another task that the Universe poses for scientists is to determine its shape. She still has not found a solution.
Today it is also unclear whether the space of the Universe is flat. A positive answer to this question makes it possible to use Euclidean geometry in territories of cosmic scale. The vast majority of researchers are inclined to believe that the space of the Universe is really flat and has folds only in small areas.
Closed or not?
Another interesting point: according to the Big Bang theory, the Universe does not have spatial boundaries as such, but it can be limited. Understanding this fact will become easier if you imagine a sphere: its surface has no boundaries, but is limited in area. There is no unambiguous understanding of the spatial structure of the Universe today. If it is similar to the same sphere, then theoretically movement in a straight line in an arbitrary direction will sooner or later pass through its starting point.
Many more points require careful research. Technical progress and scientific knowledge have not yet reached the level at which we can give a comprehensive answer to the question of what the Universe is. The definition that exists in astronomy and cosmology today has a large number of gaps and requires clarification. However, the rapid development of technology and the frequent scientific discoveries of recent years allow us to hope that soon many knowledge gaps will be filled.