New research has unveiled a new piece of this cosmic puzzle, pointing towards the role of nuclear fission in the creation of heavy elements throughout the universe.
For decades, scientists have been intrigued by the origin of elements heavier than iron in the periodic table. The prevailing theory suggested these elements were born from cataclysmic stellar events such as supernovae or the merger of neutron stars. However, recent studies involving old stars have revealed intriguing data suggesting the presence of nuclear fission in the universe.
Matthew Mumpower, a theoretical physicist at Los Alamos National Laboratory, emphasized the novelty of this discovery. “People have thought fission was happening in the cosmos, but to date, no one has been able to prove it,” Mumpower stated. His research indicates that superheavy nuclei, beyond the heaviest elements known, may be naturally produced.
The researchers observed a positive correlation between light precision metals like silver and rare earth nuclei such as europium across different stars. “The only plausible way this can arise among different stars is if there is a consistent process operating during the formation of the heavy elements,” Mumpower explained. After exhaustive testing, fission emerged as the only viable explanation for this trend.
“This is incredibly profound and is the first evidence of fission operating in the cosmos, confirming a theory we proposed several years ago,” Mumpower declared.
The observations suggest that elements with an atomic mass of 260, heavier than any currently on the periodic table, might exist. These findings stem from fission models developed by Mumpower and observational leadership by Ian Roederer of North Carolina State University.
Traditionally, astrophysicists believed heavy elements beyond iron were formed in supernovae or neutron star mergers. These processes involve the rapid-neutron capture process, or r-process, where atomic nuclei capture neutrons to form heavier elements. The possibility of these elements undergoing fission, splitting into lighter elements while releasing energy, had been a mystery until now.
In a 2020 paper, Mumpower first predicted the distributions of fission fragments for r-process nuclei. A subsequent study predicted the co-production of light precision metals and rare earth nuclei. Roederer’s analysis of data from 42 stars found the precise correlation predicted, providing a clear signature of fission in the creation of these elements.
“The correlation is very robust in r-process enhanced stars where we have sufficient data,” Mumpower pointed out. He explained that the creation of an atom of silver is proportionally linked to the production of heavier rare earth nuclei. “We have shown that only one mechanism can be responsible — fission,” he added.
Mumpower highlighted the significance of nuclear fission models developed at Los Alamos, initially intended for weapons research. These models have proven effective in interpreting experimental data and filling gaps where measurements are lacking. Since the cessation of nuclear weapon testing in the United States in 1992, experimental data on fission has been limited, making these models even more crucial.
In summary, this research opens a new chapter in our understanding of the universe and the formation of heavy elements. It confirms the occurrence of fission in cosmic processes while also hinting at the existence of elements beyond our current knowledge.
As Mumpower and his team continue to unravel the mysteries of the cosmos, we are reminded of the ever-evolving nature of scientific discovery and its ability to challenge and refine our understanding of the universe.
The full study was published in the journal Science.
Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.