What is dark energy?

Galaxiesbuzz
8 min readMay 17, 2024

The whole universe can be seen as a window that peeks through the veil of obscurity and reveals only a small portion of the invisible world at a time. That, together with the stars, planets, and galaxies, are only the visible tip of the cosmic iceberg. So not only this dark matter is the essence of the universe, but it remains hidden from our direct assessment because it is in the subsurface level.

What is Dark Matter?

Dark matter is kind of matter that fails to emit, absorb or reflect light, with explorer observatories unable to recognize it. In terms of the universe, dark matter remains elusive, but it is known that it rests about 27% of the universe’s total mass and energy content. The situation is starkly different from the mundane matter, or “baryonic,” matter (protons, neutrons, and electrons) which account for only a small percentage of almost 5% of the universe. While the 68% of the universe is made up of dark energy, a strange yet compelling force stretching the universe at an accelerated pace, it is still unknown as to why it exists and what it consists of.

The Discovery of Dark Matter

Zwicky, a Swiss astrophysicist, from the 30s has observed that Coma Cluster had an unknown energy not from visible matter and proposed the presence of dark substance. He then noted that the galaxies in the cluster were so speeded up that the visible mass, according to the standard theory, was unable to explain the gravitational forces necessary keep the cluster together. Zwicky put forward a missing mass idea as he called it *dunkle materie* in the hope to bridge the gap.

Besides, in the seventies the works of the American astronomer B. L. embrace another evidence. Rubin in his experiments studied the rotation curves of spiral galaxies and found that they do not decrease as much as what is predicted by the existing models at the speeds the stars orbit at.

What is special about it?

Structural Foundation of the Universe:

The Dance of Darkness states that dark matter is one of the keys to the origin and internal structure of the Universe. It is a scaffold of gravity that both galaxies and stellar systems separately develop and revolve around. If there were no dark matter, the background curvature of the universe would be positive and not large enough to counter the pressure of radiation at the beginning, which can stop the formation of galaxies.

Cosmic Microwave Background (CMB):

The CMB, comptonization of the Big Bang, give the scientists a unique chance to see how the universe was looking approximately 380000 years after its expansion. This distribution can be interpreted through the presence of dark energy, which caused matter’s gravity to induce density fluctuations as the universe expanded.

Galaxy Clusters and Lensing:

Any study of galaxy clusters, the large gravitationally split systems in the universe, ineffectually point out the importance of dark matter in the whole process. Gravity lensing, light from far away objects bent when passing a big massive object in front of them, proofs a supportive role for dark matter. The visible relationship is not adequately explained by the normal matter alone; this implies a major dark matter participation.

The Standard Model of Cosmology:

The Lambda Cold Dark Matter (ΛCDM) model, the standard cosmological model that predominantly conveys the history and dynamics of the universe, is based on the dark matter fundamentally. This model, in fact, is seen expressing that full range of observations; from the cosmic scale structure to the galaxy distribution.

The issue of the Dark Matter’s nature:

Even though it is one of the most crucial components, no one is sure what exactly dark matter is in modern physics, which remains one of the primary enigmas. Several candidates have been proposed, including:

Weakly Interacting Massive Particles (WIMPs):

WIMPs refer to hypothetical particles that can interact only through two fundamental forces: the weak nuclear force and gravity, while they are invisible to electromagnetic forces. They are discovered to be one of the major suspects for the culprit. The Large Hadron Collider (LHC) and several so-called direct detection experiments, which aim at uncovering signs of WIMPs, are among a growing number of experiments now hunting for evidence of these hypothetical particles.

Axions:

Axions is a very lightweight particle which has been suggested to play a role in the final solution of the strong CP problem in the theory of quantum chromodynamics. Likewise, they are another one of the favorite candidates that could go as the dark matter. The Axions, which are detected by the Axion Dark Matter Experiment (ADMX), are the century-old particles aimed to be determined.

family which cannot be detected through the weak nuclear force, thus forming a very elusive and unique class of the nuclides. They might definitively counter the problem of dark matter and also sit as their presumable form above all.

Modified Gravity Theories:

Some other hypotheses suggest that the dark matter may not be a form of matter but the curvature of space in itself that provides us with the force of gravity. Some of them like Economic theory — Modified Newtonian Dynamics (MOND) — make altercations to the rules of motion of the exist traditional for large-scale objects.

The hunt for Dark matter

Scientists look for the explanation of the dark matter’s existence through the joint efforts of multiple methods like the searching method, experimental accuracy, and performing theory work. Here are some of the key methods used in the search for dark matter:

Here are some of the key methods used in the search for dark matter:

  • Direct Detection:

The simplest method is via direct detection. This method involves looking for evidence of dark matter when its particles interact with ordinary material. Typically, these experiments are performed much deeper under the ground to make sure they are away from the cosmic rays and the any kind of radiation background. Sensors such as LUX-ZEPLIN (LZ) and XENON1T use large quantities of liquid xenon to create the reaction zones that are capable of detecting the smallest interactions with the dark matter particles or decays. The equipment involving it, for instance, the Fermi Gamma-ray Space Telescope, comprises the set of utensils necessary for the research.

  • Indirect Detection:

Indirect search methods are aimed at identifying particles produced when two dark matter particles interact. Instruments that are seeking dark matter, like Fermi Gamma-ray Space Telescope and the Alpha-Magnetic Spectrometer (AMS-02), go after excess of gamma rays, positrons, etc. that suggest the potential presence of dark matter.

  • Collider Experiments:

The LHC (Large Hadron Collider) and other high-energy particle colliders, for example, are capable of creating dark matter particles due to their collisions. Though dark matter has not been directly detected, scientists hope to arrive at dark matter “dynes” by investigating missing energy and momentum in these collisions.

  • Astrophysical Observations:

Studies on celestial bodies, galaxies, gravitational lensing and cosmic microwave background radiation all show clear evidence of the presence of dark matter. As an example, SDSS (Sloan Digital Sky Survey) and the upcoming Rubin Observatory will trace the distribution of dark matter in the universe. They will help us understand the distribution of dark matter in galaxies and the whole universe.

The Role of Dark Matter in the Universe — wide Cosmological Effects

Dark matter is powerful enough to be involved not only in galaxies’ structures forming but also in processes on a universe-wide level. Its presence affects several key aspects of cosmology and astrophysics. Its presence affects several key aspects of cosmology and astrophysics:

Galaxy Formation and Evolution:

Dark matter halos will serve us only as gravitational wells wherein galaxies form and generally evolve. The symmetric profile and destiny of galaxies in the Universe depend on the distribution and density of dark matter.

Cosmic Web:

The extensive architecture of the universe is commonly given the name a cosmic web, through which dark stuff multiplies the nets. She also weaves the gravitational laws happened between dark matter and the universe.

Galaxy Rotation Curves:

The analysis of galaxy rotation curves was a landmark work, advanced by Vera Rubin, which introduced the idea that the galaxies are surrounded by dark matter. The angular velocity curves observed to be flat as is the case for many spiral galaxies cannot sufficiently be explained by visible matter alone and therefore demands the addition of dark matter to explain this feature.

Dark Matter and Black Holes:

The union between dark matter and black holes is a rich topic of scientific investigation. Likewise, being affected by the gravitational impact, dark matter can be gathered up around black holes which in turn influences black holes to grow and evolve. While dark matter could be clarified by black holes due to their gravitational effects, the reverse argument is also evident.

Entering a new Era of Creation

The investigation of the dark matter is probably the most specifying and difficult area in physics today. The improvement of technology and inventions of new methods of seeing the dark matter will has the possibility of unveiling the real nature of dark matter. Coming experiments and missions like the James Webb Space Telescope (JWST) and the Euclid Mission from the European Space Agency will give us more than we can visualize of obscure matter location and its score card.

a unique representation of entering into a new era

In spite of all the researchers and modern technology intimidation the nature of dark matter remains one of the greatest mysteries of modern science. Read more:

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