Astronomer Uses 'Cosmic Fossils' to Trace Milky Way Origins

Amina Helmi, an astronomer at the University of Groningen, is studying cosmic fossils to understand how the Milky Way galaxy formed [1, 2].

This research provides a window into the deep history of the galactic neighborhood. By identifying the remnants of past collisions, scientists can reconstruct the violent events that shaped the stars and structures seen in the night sky today ^[3].

Helmi said these cosmic fossils are the remnants of past galactic collisions [1, 3]. These ancient signatures allow researchers to trace the evolution of the galaxy over vast stretches of time. Helmi said vast cosmic collisions over tens of billions of years ^[1] have shaped the galaxy into the Milky Way that is visible today ^[3].

Based at the University of Groningen in the north of the Netherlands, Helmi focuses on the specific movements and compositions of stars to identify which were born in the Milky Way and which were absorbed from other galaxies [1, 2]. This process of galactic archaeology helps map the growth of the system through a series of mergers and acquisitions.

The study of these fossils is essential for understanding the broader lifecycle of galaxies. Because the Milky Way is the only galaxy where astronomers can observe individual stars in such detail, it serves as a primary laboratory for studying the physics of galactic formation ^[3].

Helmi's work continues to refine the timeline of these events. The process of gathering and analyzing this data requires precise measurements of stellar velocities and chemical abundances to ensure the identified fossils are truly remnants of external systems [1, 3].