The Bullet Cluster (1E 0657-56) shows a high-velocity collision between two galaxy clusters at approximately 4500 to 4700 km/s. X-ray imaging reveals the hot intracluster gas in characteristic shock fronts, while weak-lensing maps reveal mass concentrations that are spatially offset from the gas peaks. The lensing peaks lead the gas in the direction of motion (Clowe 2006; Markevitch 2007). The observation is widely cited as direct evidence that the lensing mass is collisionless dark matter that passed through the collision unimpeded while the gas drag-coupled and lagged behind.
The standard model interprets the Bullet Cluster offset as proving that lensing mass is collisionless dark-matter particles. The framework also requires the collision velocity (~4500 km/s) to be reproducible from hierarchical-merger predictions for cluster collisions at the observed redshift, a velocity that sits at the upper edge of, or somewhat exceeds, what standard structure-formation simulations naturally produce.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field that became our visible universe. SCT has no dark-matter particle. The Bullet Cluster mass-vs-gas offset is therefore not direct evidence for collisionless DM. Instead, it is a signature of the coherent-mesh gravitational contribution that travels with the galaxies during the cluster collision while the gas drag-couples to itself.
The galaxies in each cluster carry both their own baryonic mass and the coherent-mesh contribution Φ_mesh from the comoving sub-cluster substructure they share frames with (P45, P46, P47). When the two clusters collide, the galaxies and their associated mesh contribution pass through each other essentially collisionlessly. Not because there is a DM particle, but because the galactic baryonic mass plus the mesh contribution from comoving substructure carries mass-equivalent gravitational influence without participating in the gas-drag interactions. The X-ray-emitting gas, by contrast, hydrodynamically interacts with the gas of the other cluster through ram-pressure stripping and shock heating, lagging behind. The result is exactly the observed offset: the lensing peaks track the galaxies (which carry the mesh contribution) while the X-ray peaks track the gas (which does not).
The high collision velocity ~4500 km/s is consistent with cascade-seeded structure inheriting high relative velocities from the parent-collision history. SCT does not require fine-tuning hierarchical-merger histories to produce the observed velocity; collision-cascade structure formation naturally produces a wider distribution of cluster-collision velocities than ΛCDM's hierarchical-only mechanism allows.
PARTIAL. Paper 13 preliminary SCT estimate of the Bullet Cluster lensing-X-ray offset is approximately 390 kpc, a factor 1.8 short of the observed 720 kpc. The full SCT merger simulation (with proper Bullet Cluster initial conditions, 512³ gas + 512³ for the mesh-contribution distribution) has not yet been executed; it is an open task in SCTOPEN. The qualitative M6 mechanism (gas drag while mesh-bearing galaxies pass through) is correct; the quantitative match awaits the full simulation. Until that simulation is run and matches observation, the Bullet Cluster cannot be claimed as a clean SCT win. It is a partial resolution with a known quantitative gap.
Confirmed identification of mass peaks tracking neither galaxies nor the predicted mesh contribution but a separate distinct DM component would refute the no-DM-particle interpretation. The full SCT merger simulation producing a quantitative offset substantially less than 400 kpc or substantially greater than 1000 kpc would refute the M6 quantitative match. JWST + ALMA + Chandra precision multi-wavelength observations of additional cluster-collision systems will provide tests of the M6 framework across a population of mergers.