This artist’s impression shows two tiny but very dense neutron stars merging and exploding as a kilonova. Such objects are the main source of very heavy chemical elements, such as gold and platinum, in the Universe. The detection of one element, strontium (Sr), has now been confirmed using data from the X-shooter instrument on ESO’s Very Large Telescope.More information and download options: http://www.eso.org/public/videos/eso1917b/Credit:ESO/L. Calçada