Unveiling Galactic Evolution through Galaxy Mergers

An Australian astronomer has solved a century-old mystery of galactic evolution by analyzing optical and infrared images of nearby galaxies. The study reveals that spiral galaxies reside between two types of lenticular galaxies: old and dust-poor, and dust-rich, which are formed through galaxy mergers. The research redraws the galaxy sequence and provides an evolutionary pathway through a galaxy wedding sequence. The Milky Way was likely once a dust-poor lenticular galaxy that accreted material and evolved into a spiral galaxy. The study also explains the formation of elliptical-shaped galaxies and the most massive galaxies observed in galaxy clusters.