Which process explains the creation of heavier elements beyond iron in the universe?

The creation of heavier elements beyond iron in the universe is primarily explained by the rapid neutron capture process, commonly referred to as the r-process. This process occurs in environments with an abundance of neutrons, which allow atomic nuclei to rapidly capture neutrons before they can undergo beta decay.

During events like supernova explosions or neutron star mergers, extreme conditions lead to the presence of a high flux of neutrons. In these environments, lighter elements can quickly capture neutrons, building up heavier nuclei through a series of reactions. The r-process is instrumental in forming heavy elements such as gold, platinum, and uranium, which cannot be produced through ordinary stellar nuclear fusion because those reactions do not provide the necessary neutron abundance.

Understanding this process is crucial for comprehending the nucleosynthesis of elements in the universe, especially for understanding the origins of heavy elements that are often found on Earth or in astrophysical observations.