This composite image shows the Bullet cluster, galaxy cluster 1E0657-556, which formed after two galaxy clusters collided. The Chandra X-ray Observatory imaged hot gas (pink), where most of the cluster's normal matter resides. Magellan and the Hubble Space Telescope imaged surrounding galaxies (orange and white) in visible light. Dark matter (blue) was detected through gravitational lensing.
X-ray: NASA/CXC/M. Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D. Clowe et al.; Lensing: NASA/STScI; ESO WFI; Magellan/U.Arizona/D. Clowe et al.