Title: A Multi-Scale Dynamic Microscope for the Milky Way: From the Census of Stellar Systems to Probing Fundamental Physics and Galactic Sub-Structures

Speaker: Professor Haijun Tian (Hangzhou Dianzi University)

Time: 16:00pm, July 15, 2026

Location: Tencent Meeting 692-121-275

Abstract: Modern surveys have overturned the classical paradigm of a smooth, steady-state Milky Way, revealing a dynamically perturbed, non-equilibrium disc rich in phase-space wrinkles and large-scale asymmetries. This review presents a data-driven framework that leverages the systematic properties of multi-scale stellar tracers to connect observations of macroscopic asymmetries with constraints on local dark dynamics and fundamental physics. We navigate this landscape across three complementary regimes: individual stellar kinematics map global Galactic perturbations on macroscopic scales; wide binaries provide sensitive probes of gravity and local tidal environments on microscopic scales; and 3-kpc phase-space-coherent structures such as the Stellar Snake trace mesoscopic perturbations and dynamical coherence within the Galactic potential. We further elucidate the potential of deploying these multi-scale bricks and ribbons as a coordinated dynamical microscope. Wide-binary tidal truncations and kinematic fractures in Stellar Snakes can be used to search for compact dark-matter subhalos, test gravity in extremely weak-acceleration regimes, and cross-examine the dynamical coherence of macroscopic structures such as the Radcliffe Wave. This integrated platform provides a robust, data-validated roadmap for probing both the dark components and the fundamental laws of the local Universe.