The Galactic origin of Earth's gold

This week a research paper was released with information about the most likely origin of all of Earth's most notorious precious metal. Two neutron stars, 4.6-billion years ago, smashed their bodies together and splashed out waves of matter, a bit of which eventually came to rest in our still-forming solar system.

Our planet's gold has been around for a real long time, and it didn't come from the same place as most of the rest of our Earth. Researchers Szabolcs Marka at Columbia University and Imre Bartos at the University of Florida published a paper in the scientific journal Nature. This paper had a focus on the nearby neutron-star merger that's the most likely source for several metals on our modern Earth.

This event took place approximately 80 million years before the formation of our very own Solar System. That's nor particularly long ago, given the relative age of our Solar System (around 4.571 billion years old).

The event was calculated to have taken place around 300 parsecs away from the pre-solar nebula. Parsecs, here, Star Wars fans, is still a measure of distance – just as it's so often misinterpreted via Han Solo. Our Milky Way is 100,000 light years in diameter. The star collision took place just 1000 light years from where our current Solar System resides today.

The research paper released this month suggested that approximately 0.3-percent of Earth's "heaviest elements" came from this star collision event. That includes gold, platinum, and uranium too.

"It sheds bright light on the processes involved in the origin and composition of our solar system," said BVartos. "[This data] will initiate a new type of quest within disciplines, such as chemistry, biology and geology, to solve the cosmic puzzle."

You can read more about this subject in the paper "A nearby neutron-star merger explains the actinide abundances in the early Solar System." This paper appears in Nature volume 569, pages 85–88 (2019) and was authored by astrophysicists Imre Bartos and Szabolcs Marka. You can find this paper with code DOI:10.5281/zenodo.2556447 and datasets generated and/or analyzed can be found therein.