Milky Way’s Spiral Motion Revealed | Gaia Mission Discovers Galactic Ripple High-precision data from the ESA Gaia mission reveals that stars near the Sun are not moving smoothly. Instead, they form a spiral pattern in space and velocity, known as a phase-space spiral. This structure shows that the Milky Way’s disk is still dynamically oscillating, likely caused by a past encounter with the Sagittarius dwarf galaxy. The discovery reveals that the Milky Way is a responsive, evolving system, with s