50 years ago, scientists didn’t know where heavy elements came from

Excerpt from the December 20, 1969 issue of Science News


Heavy elements probably aren’t created by an ordinary star exploding, or a supernova, the remnants of which are shown in this infrared and X-ray compsite image. But scientists now have seen these elements created in the collision of two neutron stars. Regular supernovas (like the one in this image created with infrared and X-ray data) probably can’t form heavy elements, but powerful, more exotic supernovas might.

NASA Goddard

December 20, 1969 cover

Seeking the places where the elements are madeScience 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).

Sofie Bates was the Fall 2019 intern at Science News. She holds an undergraduate degree in genetics and a master’s degree in science communication.

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