New analyzes reveal that the Milky Way has suffered collisions and may face future impact with a neighboring galaxy
New information about the formation and development of the Milky Way has been obtained through recent studies in the field of galactic astronomy using broad sets of stellar data. As detailed by The Conversation, researchers like Vasily Belokurov have examined the motion and chemical composition of billions of stars to reconstruct the complex history of our galaxy.
Evidence suggests that the Milky Way underwent a major collision with another galactic system billions of years ago, an event that left permanent marks on its internal structure. Furthermore, ongoing interactions with nearby galaxies continue to alter their shape and dynamics.
The work, which is based on information from space observatories and large astronomical surveys, also seeks to unravel the distribution of dark matter, an invisible component that exerts a crucial gravitational influence on the stability of galaxies.
Evidence of major changes in the Milky Way’s trajectory over time
The reconstruction of the Milky Way’s journey is possible thanks to a type of research that uses the stars themselves as natural archives of their evolution. A study published in The Astrophysical Journal Letters, based on data from the Sloan Digital Sky Survey and the Gaia mission, demonstrated that precise mapping of stellar positions and movements allows us to identify groups of stars that did not originate in our galaxy.
These stars, called migrants, exhibit routes and chemical compositions that diverge from stars formed in the galactic disk. The analysis presented in the study suggests that this behavior indicates an external provenance, connected to smaller galaxies that were progressively assimilated over time, acting as true cosmic “fossils” of past events.
One of the biggest proofs of this ancient merger is the structure known as Gaia-Sausage-Enceladus, interpreted as the remnant of a galaxy that collided with the Milky Way between 8 and 11 billion years ago. This event would have redrawn the galactic disk and spread stars to its most distant regions.
In addition to the physical impact on the structure, the encounter would also have modified the distribution of the dark matter halo, the invisible sphere that surrounds the galaxy and concentrates most of its gravitational mass.
Recent impacts and the constant evolution of our galactic system
Although the Milky Way has experienced a long period of relative stability after the old collisions, new external forces are once again acting on its structure, indicating the possibility of a new clash. Researchers describe that the Large Magellanic Cloud exerts a significant gravitational influence on our main galaxy.
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This interaction causes gradual deformations in the galactic halo and disturbs the dynamic balance of the Milky Way. The process develops slowly, but uninterruptedly, confirming that the galaxy remains in constant transformation.
The most recent data indicates that this relationship between the two galaxies could evolve into an even more intense interaction in the future, in a pattern that echoes merger events observed in past eras.
The study is based on the assumption that galaxies are not static entities, but systems in continuous restructuring. The analysis of vast stellar databases has made it possible to identify movement patterns that reveal collision episodes in the distant past of the Milky Way.
These records show that a portion of the stars observed today have an external origin, having been incorporated during the merger with smaller galaxies. This process contributed to the formation of the stellar halo and the redistribution of globular clusters.
Dark matter emerges as a central element in this reconstruction, since its presence determines the shape and gravitational extent of the galaxy. Studies indicate that the dark halo may have been shaped by ancient interactions and remains sensitive to new galactic approaches.
