Scientists have discovered the first signs of nuclear fission occurring between stars. This discovery supports the idea that when neutron stars collide with each other, they create “superheavy” elements that are heavier than the heaviest elements of the periodic table, which then break apart. nuclear fission to birth elements like gold in your jewelry.
Nuclear fission is basically the opposite. nuclear fusion. Nuclear fusion refers to the splitting of lighter elements to form heavier elements, while nuclear fission is a process that sees the energy released when heavy elements break down to form lighter elements. Nuclear fission is also quite well known. In fact, this is the basis of the energy-producing nuclear power plants here. Soil – however, it did not appear to occur between stars before now.
“People thought fission was occurring in the universe, but until now no one could prove it,” said study co-author Matthew Mumpower, a scientist at Los Alamos National Laboratory. he said in a statement.
The research team, led by North Carolina State University scientist Ian Roederer, explored data on a wide range of elements in stars and discovered the first evidence that nuclear fission can take effect when neutron stars merge. These findings may help solve the mystery of his whereabouts. UniverseThe heavy elements of are coming.
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Scientists know that nuclear fusion is not only the primary source of energy for stars, but also the force that forms various elements, the “heaviest” of which is iron.
But for heavier elements such as gold and uranium, the picture of so-called nucleosynthesis was a little more mysterious. Scientists suspect that these valuable and rare heavy elements were formed by the formation of two incredibly dense dead stars. neutron stars — collide and combine, creating an environment so violent that elements cannot be created even in the most turbulent hearts of stars.
The evidence of nuclear fission discovered by Mumpower and his team comes in the form of correlations between “light sensitive metals” such as silver and “rare earth nuclei” such as europium seen in some stars. Scientists found that when one of these groups of elements increased, the corresponding elements in the other group also increased.
The team’s research also shows that there are elements with atomic masses. protons And neutrons in an atomic nucleus – more than 260 may exist around neutron star collisions, even if this existence is brief. This is much heavier than many elements at the “heavy end” of the periodic table.
“The only plausible way this could occur between different stars is if a consistent process is operating during the formation of heavy elements,” Mumpower said. “This is incredibly deep and is the first evidence of fission operating in the cosmos, confirming a theory we proposed several years ago.”
“As we get more observations, the cosmos is saying, ‘Hey, there’s a signature here, and it can only come from fission.'”
Neutron stars and nuclear fission
Neutron stars are created when massive stars run out of fuel supplies for their internal nuclear fusion processes; This means energy that supports them against pushing them inward. gravity stops. As the outer layers of these dying stars blow away, stellar cores with masses of one to two times the mass emerge. Sun It will collapse to a width of approximately 12 miles (20 kilometers).
This core collapse is happening so fast electrons and protons are forced together, creating a neutron sea so dense that even just a tablespoon of this neutron star “matter” would weigh more than 1 billion tons if brought to Earth.
These extreme stars orbit each other when present in a binary pair. And as they spin around each other, they lose angular momentum because they emit abstract waves in space-time. gravity waves. This causes neutron stars to eventually collide, merge, and create a very violent environment, which is unsurprising given their extreme and exotic nature.
This eventual neutron star merger releases abundant free neutrons, particles normally bound to protons in the atomic nucleus. This could allow other atomic nuclei in these environments to quickly capture these free neutrons; This process is called fast neutron capture or the “r-process.” This allows the atomic nucleus to become heavier, creating unstable superheavy elements. These superheavy elements can then undergo fission into lighter, stable elements such as gold.
In 2020, Mumpower predicted how “splitting fragments” of nuclei created by the r-process would be distributed. Following this, Mumpower collaborator and TRIUMF scientist Nicole Vassh calculated how the r-process would lead to the co-production of rare earth nuclei such as europium, gadolinium, dysprosium, as well as light precision metals such as ruthenium, rhodium, palladium and silver. and holmium.
This prediction can be tested not only by looking at neutron star mergers, but also by looking at the abundance of elements enriched in material created by the r-process in stars.
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This new research looked at 42 stars and found the exact correlation predicted by Vassh; thus showed a clear signature of fission and decay of elements heavier than those found in the periodic table; It also confirmed that neutron star collisions are actually places where elements heavier than itself are found. iron is forged.
“The correlation is very strong in r-process enhanced stars for which we have sufficient data. time nature produces a atom It also produces rare earth cores that are heavier in proportion to silver. Mumpower concluded: “The composition of these element groups is in the same direction.” “We showed that only one mechanism could be responsible – fission – and people have been thinking about this since the 1950s.”
The team’s research was published in the December 6 issue of the journal Science.