subcluster motion Lensing mass peak (blue contours) Lensing mass peak (blue contours) X-ray gas (pink/red) ~85–90% of baryonic mass ~84% of total mass Gravitational lensing mass (DM + galaxies) Hot intracluster gas (X-ray) Galaxies The mass doesn't follow the baryons — it follows the galaxies
Figure: Schematic of the Bullet Cluster post-collision morphology. Blue dashed contours show gravitational lensing mass peaks, centered on the galaxy distributions (orange dots) — not on the X-ray gas (pink/red), which contains the large majority of baryonic mass. The subcluster's gas has been stripped into the characteristic bow-shock "bullet" shape. The spatial offset between lensing mass and gas (~150–270 kpc) is the key observation.