The dark universe remains one of the biggest mysteries facing physicists today. The visible universe that we observe, consisting of stars, galaxies, and the known matter, makes up only about 5% of the contents of the universe. The remaining 95% is composed of what is known as dark energy and dark matter.
Dark matter constitutes approximately 27% of the universe's content. It is invisible and does not interact through traditional means with light or ordinary matter. Its presence is believed to exert gravitational effects on galaxies and stars, influencing the formation of large-scale cosmic structures.
Dark energy makes up about 68% of the universe's content. It is a mysterious force that accelerates the expansion of the universe. It is believed to have a negative pressure effect, causing the universe to expand at an accelerating rate.
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Current Research and Future Challenges in the fields of dark energy and dark matter focus on understanding their nature and origin. Numerous theoretical models attempt to explain these mysterious phenomena, and current research aims to discover new clues that may help solve this grand cosmic puzzle.
With our current understanding of the universe, comprehending dark energy and dark matter remains one of the greatest scientific challenges awaiting discovery and understanding in the future.
Definition of Dark Energy:
Dark energy is a concept in cosmology that refers to a mysterious form of energy filling the empty spaces between galaxies and causing the acceleration of cosmic expansion. Dark energy is thought to constitute about 68% of the universe's energy content and indirectly influences its evolution and expansion. Dark energy does not emit or absorb light but manifests its existence through its gravitational effects on the observable universe.
Definition of Dark Matter:
Dark matter is another type of matter in the universe that is invisible and does not emit light or electromagnetic radiation. Dark matter constitutes about 27% of the universe's contents and affects celestial bodies due to its gravitational force. This matter is non-radiative and interacts weakly with ordinary matter, making it difficult to detect through traditional observation methods such as visible light or X-rays.
Dark energy and dark matter together constitute the vast majority of the universe, and despite being largely mysterious, understanding them represents a significant challenge for physicists and cosmologists today.
Theories of Dark Energy:
The theory of dark energy is not a specific individual theory but a concept based on accumulated evidence from astronomical observations and computer simulations of cosmic evolution. Dark energy is a fundamental hypothesis for explaining certain physical phenomena that current theories have not fully explained with the presence of ordinary matter and known energy.
There are several theories and assumptions regarding the nature of dark energy, including:
Negative vacuum energy: This hypothesis was introduced by Albert Einstein in his theory of general relativity, where he introduced a term called the "cosmological constant" to achieve equilibrium in cosmic expansion. It is assumed that this constant represents dark energy expressed by a negative pressure force.
Dark cosmic energy: This hypothesis suggests the existence of a negative or positive energy field with properties contrary to ordinary matter and other forms of energy.
Other models of dark energy: These include various hypotheses that interpret dark energy as a result of phenomena in nuclear physics or quantum physics.
The goal of these theories is to explain observed phenomena such as cosmic expansion acceleration and the distribution of large structures in the universe better than classical theories can. Although much research, simulation, and observation are still needed to understand dark energy more fully, current hypotheses are a crucial part of the current understanding of the universe's formation and evolution.
Relationship between Dark Energy and Cosmic Expansion:
The relationship between dark energy and cosmic expansion lies in the effects exerted by dark energy on the rate of cosmic expansion. Here are some key points that illustrate this relationship:
Effect of dark energy on the acceleration of expansion: Dark energy is believed to constitute about 68% of the universe's contents and significantly contributes to the acceleration of cosmic expansion. Instead of slowing down expansion due to gravity, the presence of dark energy leads to an increase in the speed of cosmic expansion at an accelerating rate over time.
Constant cosmic hypothesis: One of the main hypotheses for dark energy is that it represents the "cosmological constant" proposed by Albert Einstein in his theory of general relativity. This constant expresses negative energy in space, pushing objects away from each other, contributing to the accelerated expansion of the universe.
Astronomical evidence of expansion acceleration: Astronomical research and advanced cosmic observation have shown that galaxies and galaxy clusters are moving away from each other at a faster rate than expected, supporting the hypothesis of the existence of dark energy contributing to the accelerated expansion of the universe.
In general, the presence of dark energy affects the structure and evolution of the universe through accelerating its expansion. This poses a significant challenge for physicists and astronomers in understanding its nature and actual impact on the observable and perceptible universe.
Definition of the Universe:
The universe is the comprehensive sum of everything in outer space, including stars, galaxies, dust, gases, energy, matter, and everything occupying space and interacting with each other. It is the gigantic entity that encompasses everything we know and can see in the visible and dark universe.
In detail, the universe can be divided into major components:
Galaxies:
These are massive clusters of stars, gases, and other astronomical materials, forming fundamental structures in the universe, such as our Milky Way galaxy and other galaxies like Andromeda.
Stars:
These are massive masses of hot gases that emit light and heat due to nuclear fusion reactions in their cores, forming the basic chemical elements of the universe.
Dark matter:
Includes dark matter and dark energy, which constitute about 95% of the contents of the universe and greatly influence the formation and evolution of cosmic structures.
Interstellar space:
This is the vacuum surrounding stars and galaxies, containing dust, gases, and energy scattered throughout the universe.
Dark energy:
Refers to the dark energy that constitutes a significant portion of cosmic energy and contributes to the acceleration of cosmic expansion.
The universe as a concept encompasses everything in outer space, from tiny particles to giant galaxies, and is the subject of continuous studies and research in various scientific fields such as astronomy, physics, chemistry, and space science.
How Do We Know Dark Energy Exists?
We know about the existence of dark matter through its observable gravitational effects in the universe, despite our inability to directly see it. Evidence includes the following points:
Studying the motion of celestial bodies such as galaxies and galaxy clusters, we find that their rotational speeds at the outer edges are much higher than can be explained by gravity resulting from visible mass alone, such as stars and visible gases. This increase in rotational speeds indicates the presence of additional quantities of invisible matter that significantly affect the rotational motion of galaxies, and these quantities are considered dark matter.
In addition, evidence relies on cosmic studies of spectral distributions and large-scale structures in the current universe, such as the distribution of gases and materials. These evidences are manifested in theoretical cosmological models indicating that large quantities of dark matter significantly affect the development and structure of the universe, where its presence constitutes a large and important part of our current understanding of cosmology and the universe's evolution.
Exploring dark matter remains one of the greatest scientific challenges in modern physics, as this mysterious phenomenon continues to be the focus of interest for scientists and researchers worldwide. Through its unexplained gravitational effects and its impact on large cosmic formations, dark matter enhances our understanding of the universe's formation and evolution.
Although we still face many challenges in understanding its nature and components accurately, increasing evidence and advanced astronomical analyses reinforce our confidence in its existence and importance. Research and studies in this field are expected to continue, potentially uncovering more secrets about this mysterious phenomenon and its role in the structure of the universe.
As scientific understanding continues to evolve, studies of dark matter can contribute to expanding the boundaries of our knowledge about the origin and future of the universe, making this field one of the most important research subjects in astronomy and cosmology in the coming years.