Here we present convincing evidence for a cosmic collision. This extraordinary event is occurring within the Perseus galaxy cluster, which is about 250 million light-years from Earth. This cluster is an immense collection of thousands of galaxies. It is receding from our planet at a remarkable 3,335 miles per second (5,366 kilometers per second) as the universe continues to expand. This finding opens a new window into a fascinating and complex history for this celestial neighborhood. It contradicts the old assumption that it was just a cushy galaxy cluster.
The Perseus galaxy cluster spans an amazing 11.6 million light-years. It’s 100 times wider than the Milky Way! Read more in Our Ocean in Focus. Its tremendous size and complexity provide unparalleled opportunities for dynamic scientific observations and discoveries. Researchers previously believed that the cluster had a stable configuration. New evidence has shown them that it’s been a far more tumultuous history than they ever imagined.
Subcluster and Mass Bridge
In this paper, the new findings led to a thrilling discovery. At the center lies a subcluster with 10 times the mass of the Milky way. This subcluster is linked to the primary main galaxy cluster with what is referred to as a “mass bridge,” reaching about 1.4 million light-years. This bridge is a compelling testimonial to complex gravitational interactions between the two clusters.
The massive bridge has been key to interpreting the lopsided structure of the Perseus galaxy cluster. The gravitational pull between the main cluster and the subcluster has influenced its structure, revealing that the cluster is not as relaxed as scientists once thought.
“The result surprised me, because I considered Perseus to be a relaxed cluster,” – HyeongHan Kim
Historical Cosmic Events
Despite being the current heavyweight champion of the known universe, the Perseus galaxy cluster has had a very hard cosmic past. The subcluster’s first approach through the center of the main cluster occurred about 2 billion years ago. During this close encounter, gravitational forces with Earth slowed it down and pulled it back from its trajectory towards the Sun. The subcluster then passed through the outskirts of the main cluster again, about 3 billion years later, adding to their interaction.
According to subsequent analyses, this subcluster crossed paths for the third time around 750 million years ago. Further, this suggests a cycle of feedback of continued interaction that has profoundly influenced both spaces. Such events are key pieces of the puzzle to understand how galaxies evolve and collide over the gigantic timescales of the universe.
Cold Fronts and Galactic Dynamics
Along with these major discoveries, researchers found “cold fronts” inside the Perseus galaxy cluster. Discovered in 2012, these cold fronts likely form when galaxy clusters collide, marking boundaries where hot gas from one cluster collides with cooler, denser gas from another.
These cold fronts are an additional piece of evidence for these past collisions and interactions. Investigating these phenomena allows astronomers to understand how galaxies and clusters evolve in different thermal environments.
“As we do not know the intrinsic shape of each galaxy, we cannot infer how much the image of the background galaxies are distorted,” – HyeongHan Kim
This sobering realization illustrates the difficulty of investigating our universe’s largest structures. Researchers have to account for a multitude of variables that could affect the outcome of their study. As the mission to study the Perseus cluster continues, more discoveries are sure to provide new knowledge into the mechanisms causing and controlling galaxy evolution.
