The Milky Way’s Past, Present, and Future through an Extragalactic Lens

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Once thought to be clumpy, turbulent systems, high-redshift galaxies are now revealed by the James Webb Space Telescope to host spiral arms, bars, and even thick and thin disks. These discoveries raise fundamental questions about how disk galaxies assemble, how quickly they settle into ordered rotation, and what physical processes shape their long-term evolution. Closer to home, Gaia together with Galactic archaeology surveys such as GALAH and APOGEE, reveal a complex picture in which the Milky Way is shaped through minor collisions with satellite galaxies and the delicate interplay of chemical and dynamical processes. Yet there is still no consensus on how its distinct thin and thick disks formed and evolved, and the answer is unlikely to come from studying the Milky Way alone. In this talk, I will present new results from the GECKOS survey, a VLT/MUSE program targeting 36 edge-on Milky-Way-mass galaxies that provides detailed, spatially resolved chemistry and kinematics across a representative sample of local analogues. Our data are revealing a variety of kinematic sub-structures that require a contemporary view of galaxy morphology, expanding the traditional picture and linking the Milky Way’s kinematic complexity with that seen in other galaxies. I will show how linking GECKOS with highly resolved face-on surveys such as PHANGS and MAUVE, together with large multi-object IFS surveys like SAMI and Hector, allows us to connect bars and spiral features to the vertical structures seen in GECKOS. Alongside these latest results, I will also discuss our work on placing the Milky Way in a cosmological context and explore the likely outcome of the future collision between our Galaxy and Andromeda.