8 December 2025

Photo: Stephan Rosswog

Numerical Relativity supercomputer simulation of two colliding neutron stars. The key aim of these simulations is to predict the gravitational wave signals, the newly forged heavy elements and to understand which electromagnetic flashes they produce.

The ENGRAVE collaboration has been awarded the new ‘Into Change Award’, which comes with a prize money of 1 million euros. The collaboration has made it possible to trace the origins of the Universe’s heaviest elements, which are forged in the aftermath of neutron star mergers.

ENGRAVE (Electromagnetic counterparts of gravitational wave sources at the Very Large Telescope) is an international collaboration of astronomers focused on gravitational wave events. The collaboration has over 250 researchers, including Quantum Universe Principal Investigator Stephan Rosswog. The collaboration has shown how the universe’s heaviest elements are forged in rare kilonova explosions. These events act as factories for heavy elements that make up about half of the periodic table, including precious metals, rare earths and uranium. In revealing this process, the team is shedding light on the very building blocks of humanity.

“This is wonderful news,” says Rosswog. “For half a century the general consensus was that heavy elements are forged when stars explode as supernovae. Our theoretical work from 1999 on a more ‘exotic’ alternative scenario, the collision of two neutron stars, clearly showed that such collisions must be major sources of the heaviest elements. We had been continuously working on predicting potentially observable signals, e.g., gravitational waves and electromagnetic flashes, from such events. It is wonderful that the observations of the ENGRAVE team could actually prove that neutron star mergers are indeed cosmic sources of heavy elements!