The Eastern Bubbles (eROSITA + Fermi) extend from the Galactic Center with significant east-west asymmetry: the northern bubble tilts west, the eastern edge shows sharp brightness enhancement (Predehl 2020; Ponti 2021). Standard symmetric AGN-feedback or starburst models cannot reproduce the asymmetric morphology without invoking specific tilted-jet histories or asymmetric ambient-medium configurations.
The standard model has Galactic Center bubbles inflated by symmetric SMBH outflow or starburst expanding into uniform halo. Recovering the observed asymmetry demands tilted central engine, asymmetric ambient medium, or specific jet-precession history, none of which is parsimonious within minimal ΛCDM.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, the Eastern Bubble asymmetry is the same sibling-pocket gravitational-influence signature that produces the Fermi Bubbles asymmetry (recid 198). The Galactic Center hosts a cascade-seeded SMBH (P22, P46) inherited from prior cycles (P25, P28), driving the past outflow events that inflated the bubbles into cascade-thermalized inherited gas.
Sibling pockets at multi-Mpc to gigaparsec scales (P58, P59, P60) provide asymmetric gravitational influence on the Galactic Center outflow direction, naturally producing the observed east-west asymmetry. The eastern brightness enhancement reflects the higher-density gas environment encountered on that side, consistent with the cosmic-web cascade-stream geometry around the Milky Way.
Angular-momentum inheritance (P31, P32) gives the Galactic Center its inherited J vector that constrains the outflow direction. Gravitational superposition (P50, P51, P52) provides the cosmic-web context where the Milky Way + nearby siblings together host the bubble structure. The same M9 framework that produces the Fermi Bubbles asymmetry (recid 198), dark flow (recid 12), bulk-flow excess (recid 87), and the broader sibling-pocket gravitational-influence phenomenology accounts for the Eastern Bubbles asymmetry as a sibling-pocket signature.
If precision eROSITA + future X-ray surveys find the Eastern Bubble asymmetry fully reproducible by standard tilted-jet or asymmetric-ambient-medium models at the 5% level (no sibling-pocket signature), the M9 explanation is refuted. The signature SCT prediction is the asymmetry direction correlating with sibling-pocket cosmic-web direction indicators.