Seeking the places where the elements are made — Science News, December 20, 1969
One of the outstanding questions in astrophysics is whether all [variants of naturally occurring elements] have been present from the beginning of the universe.… If the nuclear manufacture was not accomplished in some big bang … then it must take place in smaller cataclysms…. A good candidate … is an exploding star, or supernova.
The Big Bang created the universe’s lighter elements, including the hydrogen and helium that formed the first stars (SN: 2/10/15). Nuclear fusion within stars creates heavier elements up to about iron, which are spewed out when these stars explode as supernovas. The merging of two neutron stars, first witnessed from Earth in 2017, revealed that many variants of elements heavier than iron are made in such smashups (SN: 11/11/17). There may be other sources, too. Some physicists think certain rare, fast-spinning supernovas may be powerful enough (SN: 6/8/19).