The Bullet Cluster (Webb & Chandra composite) - section

A collision between two massive galaxy clusters forms this striking cosmic scene known as the Bullet Cluster, located about 3.8 billion light-years away in the constellation Carina. What appears here is not just a breathtaking collection of galaxies, but also a unique laboratory for studying dark matter, one of the most mysterious components of our universe.

In this composite image, Webb’s near-infrared observations reveal thousands of galaxies and foreground stars, while data from NASA’s Chandra X-ray Observatory appear in pink, showing hot, X-ray-emitting gas left behind by the violent collision. The blue areas highlight where dark matter resides, mapped with extraordinary precision using Webb’s detailed imaging.

Normally, gas, dust, stars, and dark matter remain bound together in galaxies, even within galaxy clusters. But in this case, the hot gas has been stripped away while the dark matter continued on, unaffected. This clear separation provides compelling evidence for the existence of dark matter, which cannot be seen directly but reveals itself through its gravitational effects on visible light, bending and magnifying the galaxies behind it, much like invisible ripples distorting pebbles beneath water.