Jeon Ji-gook (left), professor of astronomy and space sciences at Yonsei University, and first author Hyung-jin Joo. Courtesy of Yonsei University
Cluster light is the light produced by stray stars between galaxies in a cluster of hundreds of galaxies. Astronomers have been debating the origins of light-producing stray stars. The claim that the wandering star was created recently and the claim that it was created in the early days of the universe clashed.
A research team in Korea has come up with research results that put an end to this debate. It succeeded in detecting the light within galaxy clusters created by stray stars in galaxy clusters in the early stages of the universe.
Ji Myeong-guk, a professor at the Department of Astronomy and Space Science at Yonsei University, announced that the research results were published in the international journal Nature on the 5th.
The research team used NASA’s Hubble Space Telescope to detect galaxy cluster infiltration created by stray stars in 10 early galaxy clusters that are only a third of the current age of the universe. The brightness of this galaxy cluster’s internal light is regarding 17% of the light produced by the cluster as a whole, similar to today’s measurements in the near universe.
The research team said, “The fact that many stray stars were discovered in young galaxy clusters means that stray stars were formed in large quantities in the early universe.” explained.
Wandering stars are expected to be used as tracers of ‘dark matter’. Dark matter accounts for 85% of the total mass of matter that makes up the universe, but its identity is still unknown. It does not interact with normal matter other than gravity and is invisible. The identity of dark matter remains one of the greatest challenges in physics in the 21st century.
Professor Ji explained why a wandering star can be used as a dark matter tracker by comparing it to an invisible man. However, if the amount of flour is insufficient, only a part of the shape such as the head or arms is visible.
Wandering stars play a role in scattering flour. It is explained that the wandering star, which has been proven to have been created in the early universe, must have interacted with dark matter through gravity while traveling around the galaxy cluster. Professor Ji said, “Where dark matter goes, the wandering star must have moved along with it.”
In 2007, Professor Ji published a study that found evidence proving the existence of dark matter using gravitational lensing. At the time, it was evaluated as the most convincing evidence in the history of dark matter research.
