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Galaxy Research is a work that goes back to the beginning

The process of combining two small galaxies to form a large galaxy ⓒ NASA
The process of combining two small galaxies to form a large galaxy ⓒ NASA

Among the galaxies that make up the universe, there are tornado-shaped galaxies and elliptical galaxies. The surprising thing is that there are hundreds of billions of galaxies in the universe of such various shapes, and how are these galaxies created?

The eighth lecture space opera, an event to uncover the secrets hidden in space and galaxies by calculating such curiosity with computer simulation, was held online on the 21st and drew the attention of viewers.

Organized by the Chaos Foundation, which was established with the aim of popularizing science, this event is designed to view everything related to the universe, including the solar system, planets, and galaxies, from various perspectives of experts.

Two galaxies merge to form one large galaxy

Ji-Hye Shin, a senior researcher at the Galactic Evolution Research Group at the Korea Astronomical Research Institute, who presented on the subject of space and galaxies realized through computer simulations said, space and galaxies are the objects of mankind's oldest curiosities.

Dr. Shin said, there are really various galaxies in the universe, and a representative way for galaxies to be formed is when two different galaxies merge into one. As galaxies have various shapes depending on the structure, density, and amount of gas, and these galaxies are known to form another shape as they merge. The problem is that these changes have progressed over billions of years, making it very difficult to observe the process.

Dr. Shin introduced that computer simulation is a tool for grasping changes in galaxies over such a long period of time, and emphasized that computer simulation through a statistical approach is the key to understanding galaxies.

This means that you can create virtual universes and galaxies through computer simulations to infer the shape of our galaxy to which the solar system belongs, or to estimate how galaxies are distributed.

As such, a representative example of the appearance of the universe and galaxies inferred by computer simulation is the theory of the cosmic giant structure hypothesis. This hypothesis, also called cosmic web structure' because the universe looks like a web-like a spider's web, is derived from the fact that there are sparse large clusters of galaxies in the universe, and these clusters are connected like long and thin filaments.

About the computer simulation used as a tool for grasping the mysteries of the universe and galaxies, Dr. Shin introduced, there are theoretical and experimental research methods.nThe experimental research method is a method of proving a hypothesis, then performing a numerical model design, and then verifying the hypothesis after observation and comparison.

Research on dark matter that holds the secrets of the universe

The lower half of Dr. Shin's lecture was filled with explanations of dark matter and galactic formation. Dark matter is a term for a matter that is presumed to exist widely in the universe but has not yet been directly observed. This concept was introduced to explain gravitational phenomena that require more matter than visible matter in various astrophysical phenomena.

Regarding the dark matter, Dr. Shin said, it has not been directly observed or detected, but evidence of the existence of dark matter, such as the stability of spiral galaxies, the speed of galactic rotation, or the gravitational lens, can be found in a number of phenomena.

Dark matter is also closely correlated with dark energy. It is known that only 4% of the universe is visible to our eyes. The remaining 96% are unknown and unknown, and the astronomical world estimates that the remainder is composed of 27% dark matter and 69% dark energy.

Computer simulations have been attempted so far to uncover the identity of dark energy that only exists theoretically, but it is true that the size of the virtual universe was limited in the existing cosmological fluid mechanics numerical simulation.

In order to uncover the secret of such dark energy, a study using a supercomputer was conducted in Korea last year. The Korea Institute of Science and Technology Information (KISTI), together with the Academy of Advanced Sciences and Korea Astronomical Research Institute, uses the 5th supercomputer Nurion to calculate space evolution and galaxy formation, HR5 (Horizon Run 5). Performed.

The research team greatly expanded the scale of the simulation at the time and reproduced it closest to the standard space model. In response, the astronomy community has evaluated HR5 as the world's largest cosmological fluid dynamics simulation led by a domestic research team.

Meanwhile, at the end of the lecture, Dr. Shin also introduced baryon, a concept contrary to dark matter. It is the norm in the existing astronomy world that only 5% of the matter that makes up the universe is only about 5% of the matter, and the remaining 95% is composed of 26% of dark matter and 69% of dark energy.

Here, the common substance visible to our eyes is called barion, and barion refers to elements such as protons, neutrons, or subatomic particles that make up general matter such as hydrogen, helium, or heavier elements.

Dr. Shin said, it is presumed that the astrophysical phenomena such as star formation, supernova explosion, and black hole formation are caused by the involvement of barion.

At the conclusion of the presentation, Dr. Shin emphasized, the work of realizing the universe and galaxies through computer simulation is probably the challenge of mankind to go back to the beginning.

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