- A catastrophic collision of two neutron stars sent a small fraction of its precious materials to Earth.
- The event occurred 4.6 billion years ago, near the Earth’s solar system.
- Nearly 0.3% of the Earth’s heaviest elements came from this cosmic event.
A growing body of evidence suggests heavy elements are produced by binary neutron-star mergers. As these mergers happen a few time in a million years, their production of heavy elements is infrequent.
The isotopes of these elements have half-lives of nearly 100 million years, and they are no longer present in our Solar System. However, signs of their abundances in the early Solar System can be found in meteorites.
Recently, researchers at the University of Florida and Columbia University identified a catastrophic collision of two neutron stars as the most likely source of coveted matter on Earth. The event occurred 4.6 billion years ago, near the Earth’s solar system, sending the planet a small fraction of its precious materials, including gold, platinum, and uranium.
Analyzing Radioactive Isotopes In Meteorites
To come up with their findings, the team examined data from ancient meteorites that were formed 4.6 billion years ago (for reference, the age of our solar system is also 4.6 billion years).
These meteorites carry the traces of radioactive isotopes that would have produced by a neutron-star collision. The researchers analyzed the decay process of these isotopes to reconstruct the time they were formed.
Reference: Nature | DOI:10.1038/s41586-019-1113-7 | Columbia News
They found that nearly 0.3% of the Earth’s heaviest elements came from this cosmic event. They then created numerical simulations of the Milky Way and compared them with the composition of meteorites.
The resulting data showed that neutron stars could have collided 100 million years before the Earth was formed and this collision might have happened within 1000 light-years from a dense gas cloud that ultimately formed our Solar System.
The final phase of a neutron-star merger | Credit: NASA
Our galaxy is alone 100,000 light-years wide, or 100x larger than the distance of this event from the birthplace of Earth. If a similar event occurred today at the same distance, the light from the explosion could outshine the whole night sky. In fact, it could end life on Earth.
But since such collisions only occur every 100,000 years in our galaxy, and ones that occur within 1000 light-years are far less often, humans aren’t in any immediate danger.
Significance Of This Research
The findings explain the processes involved in the origin and composition of the solar system. The research team believes that this study will initiate a new kind of quest across several fields including geology, biology, and chemistry, to solve the cosmic mystery. Also, it tries to explain the origin of humanity and where we are heading.
Researchers plan to study how often such collisions happened in the past in our galaxy and how they affected the formation/evolution of the Milky Way.