Scientists have discovered the first signs of nuclear fission occurring between stars. The discovery supports the idea that when neutron stars collide, “superheavy” elements, which are heavier than the heaviest elements on the periodic table, are created and then broken down. nuclear fission It gives your jewelry a gold-like element.
Nuclear fission is basically the opposite. Nuclear fusion. Nuclear fusion refers to crushing lighter elements to create heavier elements, while fission is a process that looks at the energy released when a heavy element splits to create a lighter element. Nuclear fission is also quite famous. In fact, this is the basis of nuclear power plants that produce energy. earth — but it wasn’t observed happening. Performer Until now.
“People have always thought that nuclear fission occurs in the universe, but so far no one has been able to prove it,” said study co-author Matthew Manpower, a scientist at Los Alamos National Laboratory. said in a statement.
A research team led by North Carolina State University scientist Ian Roederer studied a wide range of elements in stars to find the first evidence that nuclear fission may be at play when neutron stars merge. I searched the data. These discoveries could help solve the mystery of where it is. macrocosmThe heavy elements of come from .
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Scientists know that nuclear fusion is not only the main source of energy for stars, but also the force that forges various elements, the “heaviest” being iron.
But the whole picture of so-called nucleosynthesis of heavier elements such as gold and uranium is a little more mysterious. Scientists believe that these precious and rare heavy elements may be produced by two incredibly dense dead stars. neutron star — creating an environment violent enough to collide and fuse to create elements that even the noisiest centers of stars cannot produce.
The evidence for nuclear fission, discovered by Manpower and his research team, comes in the form of a correlation between “light precision metals” such as silver and “rare earth nuclei” such as europium, which can be found in several stars. Scientists have observed that when one of these groups of elements rises, the corresponding element in the other group also rises.
The team’s research also shows that elements have atomic mass, i.e. proton and neutron Inside the nucleus, there can be more than 260 atoms around a neutron star collision, even if their existence is short-lived. This is much heavier than many elements on the “heavy end” of the periodic table.
“The only possible way this could happen between different stars is if consistent processes are at work during the formation of heavy elements,” Manpower said. “This is incredibly profound and is the first evidence of nuclear fission occurring in the universe, supporting a theory we proposed several years ago.”
“As we get more and more observations, the universe is saying, ‘Hey, there’s a signature here, and it can only come from nuclear fission.'”
Neutron stars and nuclear fission
Neutron stars are created when a massive star reaches the end of its fuel supply for its inherent fusion process. This refers to the energy that has supported the neutron star against its own inward pressure. gravity Stop. When the outer layers of these dying stars are blown away, the star’s core becomes 1 to 2 times the mass of the star. Sun It collapses to about 12 miles (20 kilometers) wide.
This core collapse occurs so rapidly that electronicIf only a tablespoon of this neutron star’s “matter” were brought to Earth, the protons would be forced together to form a dense neutron ocean that would weigh more than a billion tons. .
When these polar stars exist in binary pairs, they spiral around each other. And as they spiral around each other, they lose angular momentum as they emit ripples in space-time, called intangible ripples. gravitational waves . This causes the neutron stars to eventually collide and merge, creating an extremely violent environment, which is understandable given their extreme and exotic nature.
This ultimate neutron star merger releases large amounts of free neutrons, particles that are normally bound to protons in atomic nuclei. This allows other nuclei in these environments to quickly capture these free neutrons. This is a process called rapid neutron capture or “r-process.” This makes the atomic nucleus heavier and creates unstable superheavy elements. These superheavy elements undergo nuclear fission and are broken down into lighter, more stable elements such as gold.
In 2020, Manpower predicted how the “fission fragments” of atomic nuclei produced in the r process would be distributed. Following this, Manpower collaborator and TRIUMF scientist Nicole Vash explains how the r-process can be used to synthesize lightweight precision metals such as ruthenium, rhodium, palladium, and silver as well as rare earth nuclei such as europium, gadolinium, and dysprosium. We calculated whether this would lead to joint production. And holmium.
This prediction can be tested not only by looking at neutron star mergers, but also by looking at the elemental richness inside the stars enriched by the material produced in the r process.
This new study examined 42 stars and found the exact correlation predicted by Vash. This showed clear signs of fission and decay of heavier elements than found on the periodic table, further supporting that neutron star collisions are indeed where elements heavier than the periodic table collide. Iron is forged.
“The correlation is very strong for r-process-enhanced stars for which there is sufficient data. time produced by natureatomIn proportion to the production of silver, heavier rare earth nuclei are also produced. “The composition of these elemental groups is well under way. We showed that only one mechanism could be responsible, fission, and people have been wondering about this problem since the 1950s. ” Manpower concluded.
The team’s research was published in the December 6 issue of the journal. science.