The formation of some of the heaviest elements in the universe occurs during the cataclysmic collision between two neutron stars. These events were confirmed by observations recently due to the detection of gravitational waves and found to emit “polluting” interstellar gas containing elements like gold and uranium. Researchers speculate that one such collision might have occurred in our vicinity prior to the formation of our Solar System. The findings reported in the journal Nature claim that approximately 0.3 percent of the Earth’s heaviest elements might have formed during this explosion. The team estimates the occurrence of this neutron star collision around 4.6 billion years ago, just 100 million years before the formation of Earth.
The composition of meteorites that are relics from the past, serves as a significant piece of evidence in this research. Neutron star collisions yield certain radioactive elements that decay over timescales lesser than 100 million years, but the resulting elements remain trapped inside meteorites. Distinct decay signature of certain isotopes provide the researchers with a lot of information.
Lead author Dr Imre Bartos, from the University of Florida, said in a statement, “Meteorites forged in the early Solar System carry the traces of radioactive isotopes”.
Co-author Dr Szabolcs Marka at Columbia University added, “As these isotopes decay they act as clocks that can be used to reconstruct the time they were created”.
The research equated the abundances of elements like thorium, uranium, and plutonium etc.in the actinide series found in meteorites with numerical simulations of the Milky Way to assess the extent of spread of elements from a neutron star merger before decaying. The researchers used this data to estimate that the catastrophic collision must have occurred close to a 1,000 light-years from the gas cloud that led to the origin of the Solar System.
Marka added, “If a comparable event happened today at a similar distance from the Solar System, the ensuing radiation could outshine the entire night sky”.