Powerful Reactions Similar to a Nuclear Bomb Observed in Space for First Time

In a landmark discovery, scientists believe they have found the first evidence of nuclear fission naturally occurring in the universe — a powerful reaction in which a neutron hits an atom and splits it into new atoms, releasing energy as it does.

The discovery is documented in a new study published in the journal Science. In it, the researchers describe how two neutron stars — extremely dense, small cores of dead stars made up of neutrons — could collide with enough force to produce a fission reaction. From there, these kinds of nuclear reactions in space could help create ultra-heavy elements, like gold, as well as yet-to-be discovered elements, the researchers say.

Specifically, the way they theorize it works is that when neutron stars collide, the neutrons are picked up by atoms to form heavier atoms. As the atoms gather neutrons, they get so heavy that they split into lighter atoms — fission.

“People have thought fission was happening in the cosmos, but to date, no one has been able to prove it,” said Matthew Mumpower, a theoretical physicist at Los Alamos National Laboratory and co-author of the new paper in a statement.

To try and prove the theory, the scientists used observations of elements around several stars — they saw that as the amount of heavy elements like europium went up, so did the amount of lighter elements, like silver.

"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," said Mumpower. "The team tested all the possibilities and fission was the only explanation that was able to reproduce the trend."

"This is incredibly profound and is the first evidence of fission operating in the cosmos, confirming a theory we proposed several years ago," he added. "As we’ve acquired more observations, the cosmos is saying hey, there’s a signature here, and it can only come from fission."

Ultimately, this could mean there are some undiscovered, very heavy elements out in the cosmos. Currently, the heaviest of the 118 confirmed elements is oganesson, which has an atomic mass of 294 (the total number of protons and neutrons found in an atom).

“The correlation is very robust in r-process enhanced stars where we have sufficient data. Every time nature produces an atom of silver, it’s also producing heavier rare earth nuclei in proportion. The composition of these element groups are in lock step,” said Mumpower. “We have shown that only one mechanism can be responsible — fission — and people have been racking brains about this since the 1950s.”