Tracing the Universe’s heaviest elements

Where do gold, platinum and uranium actually come from?

For decades, this question stood as one of cosmology’s most fundamental mysteries. The answer finally arrived in 2017 – thanks to a remarkable international effort led by a network of researchers and observatories across 13 European countries, who showed heavy elements were formed in huge amounts during the merger of two neutron stars (GW170817).

Following this historic breakthrough, these pioneers formed the ENGRAVE (Electromagnetic counterparts of gravitational wave sources at the Very Large Telescope) to unite astronomers, physicists, and cosmologists in the search for the universe’s most extreme events – collisions between neutron stars.

These rare cosmic mergers have been shown to be the factories of the heavy elements that make up two-thirds of the periodic table – including the precious metals, rare earths, and the fundamental elements that form our planet and our bodies.

From Discovery to a New Worldview

Since then, the researchers have used data from the LIGO-Virgo interferometer, ESO’s Very Large Telescope, the Hubble Space Telescope, and the James Webb Space Telescope, to document how these cosmic explosions create heavy elements through the so-called r-process – a rapid neutron-capture synthesis that occurs when a star collapses in a supernova explosion.

This ground-breaking work – published in highly cited papers in Nature, Physical Review Letters, and The Astrophysical Journal – has transformed our understanding of the chemical origins of the universe and answered one of science’s oldest questions: Where do we come from?

ENGRAVE is a model example of modern scientific collaboration:

• Joint European coordination of telescopes and data
• Open science with free access to results and datasets
• Active involvement and training of young researchers through mentoring and live observation networks
• A culture defined by curiosity, respect, responsibility, and collaboration

The project has not only changed physics – it has changed the way scientists work together across borders and disciplines. The ENGRAVE team’s discoveries were recognized as Science Magazine’s Breakthrough of the Year 2017 and have ushered in a new era of multi-messenger astronomy, where gravitational waves and light together reveal the deepest secrets of the cosmos.