Gold is one of the most valued metals on Earth, but unlike some substances that have a very clear origin that is based on the beginning of universe, like hydrogen or helium, its birth remains a mystery. Now, we know that some heavier elements like iron were forged in stars, but that theory does not sustain all materials found on Earth and does not confirm the origins of specific materials, like gold.
Anirudh Patel, a doctoral student at Columbia University in New York explains why the question matters “It’s a pretty fundamental question in terms of the origin of complex matter in the universe. It’s a fun puzzle that hasn’t actually been solved.”
The theory that gold is one of the elements that was created by a magnetized neutron stars, called magnetars was conducted by him and by Eric Burns, study co-author and astrophysicist at Louisiana State University in Baton Rouge. They took 20-year-old archival data from NASA and ESA telescopes and found that it reflected a surprising amount of evidence that supports the magnetar theory. As Burns stated “It’s answering one of the questions of the century and solving a mystery using archival data that had been nearly forgotten.”
According to the found data, magnetar giant flares could “contribute up to 10% of the total abundance of elements heavier than iron in the galaxy” and since this was a type of star that existed very early on in the creation of our universe, impacts to our planet during its formation could have been responsible for the gold we now find.
Study authors estimate that magnetar giant flares could contribute up to 10% of the total abundance of elements heavier than iron in the galaxy. Since magnetars existed relatively early in the history of the universe, the first gold could have been made this way.
How could gold be made in a magnetar?
Another theory is that when massive stars go supernova and leave behind a compact core that core can in some cases become a magnetar. Their magnetic fields are intense, and every now and then, the crust of a magnetar cracks causing a “starquake.” These starquakes can release huge bursts of radiation called giant flares, which have been observed only a handful of times. Patel, along with his advisor Brian Metzger and others, started thinking that maybe the energy from these giant flares could actually help forge heavy elements.
This process is known as the “rapid neutron-capture process,” or r-process during which atoms snatch up neutrons so quickly that they do not have time to stabilize, and then the excess neutrons decay into protons, moving the atom up the periodic table.
This theory is supported by the fact that back in 2017, scientists witnessed the collision of two neutron stars, a rare event that definitely created heavy elements like gold and platinum, but since those types of mergers take too long to happen to explain the earliest presence of these elements in the universe, magnetar flares might be a more reasonable explanation for the earlier creation of these elements.
Researchers like Jakub Cehula, Todd Thompson, and Metzger found that these flares could blast chunks of neutron-rich material off the surface of the magnetar, potentially seeding space with heavy elements. When they asked other observers if gamma rays could have been involved in element creation, they were given data from a flare that erupted back in December 2004. ESA’s INTEGRAL telescope had picked up a weird signal after the main burst that at the time made no sense to researchers, but when Patel and Metzger compared that old signal to their predictions, it was a near-perfect match.
The gamma-ray afterglow from that flare looked exactly like what they expected if heavy elements had formed and were being dispersed. Patel said, “I wasn’t thinking about anything else for the next week or two. It was the only thing on my mind.”
They backed up their findings with additional data from NASA’s RHESSI and Wind satellites, which also caught the 2004 flare and now NASA’s upcoming COSI mission a gamma-ray telescope set to launch in 2027, could confirm these results by directly identifying the elements produced in flares. For now, Patel and the team are combing through more old data, hoping that other overlooked magnetar flares might be hiding similar signals.
“It’s very cool to think about how some of the stuff in my phone or my laptop was forged in this extreme explosion of the course of our galaxy’s history,” Patel said.