The supernova remnant Cassiopeia A is the aftermath of a stellar explosion. These explosions – and other astronomical cataclysms such as neutron-star collisions – are responsible for creating the elements that are essential for life in the universe.
The image above, taken by NASA’s Chandra X-ray Observatory, shows the location of different elements in the remains of the explosion: silicon (red), sulfur (yellow), calcium (green) and iron (purple). Each of these elements produces X-rays within narrow energy ranges, allowing maps of their location to be created. The blast wave from the explosion is seen as the blue outer ring.