3D trajectory of a (single) small and massless bubble rising under the action of buoyancy in a rotating but otherwise static atmosphere. The initial bubble is released at a distance of 5 kpc from the center (just above the disk plane). The green line shows the case of a nonrotating atmosphere. In this case, the bubble moves away from the Galaxy center in the disk and then switches to a more radial trajectory. The blue curve shows the case of a slowly rotating halo (V_h ∼ 100 km s⁻¹). The bubble is now involved in rotation and motion towards larger radii. Finally, the red curve illustrates the case of fast rotation of the halo gas (V_h ∼ 200 km s⁻¹). In this case, the centrifugal force is strong, and an inverted pressure gradient pushes the bubble closer to the rotation axis.