Chandra has recently observed 1E 0657-56, a hot merging system at z = 0.3 (the "bullet" cluster), for 500 ks. I present some of the findings from this dataset. The cluster exhibits a prominent bow shock with M = 3.0 ± 0.4 (one of only two known M ≫ 1 shock fronts), which we use for a first test of the electron-ion equilibrium in an intergalactic plasma. The temperatures across the shock are consistent with instant shock-heating of the electrons; at 95% confidence, the equilibration timescale is

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... much shorter than the collisional Spitzer value. Global properties of 1E 0657-56 are also remarkable. Despite being extremely unrelaxed, the cluster fits well on the L X −T relation , yet its total mass estimated from the M −T relation is more than twice the value measured from lensing. This is consistent with simulations predicting that in the middle of a merger, global temperature and X-ray luminosity may be temporarily boosted by a large factor.