Scientists believe that lighter elements such as hydrogen and helium, and even small amounts of lithium, likely existed early after the universe was formed in the Big Bang 13.8 billion years ago, CNN notes.
The exploding stars then released heavier elements like iron, which became part of the newborn stars and planets. But the distribution of gold, which is heavier than iron, throughout the universe remains a mystery to astrophysicists.
“This is a pretty fundamental question in terms of the origin of complex matter in the universe,” said Anirudh Patel, lead author of the study published in the Astrophysical Journal Letters and a doctoral student in the physics department at Columbia University in New York. “It’s a fun puzzle that hasn’t really been solved yet.”
Previously, gold production in space was associated only with collisions of neutron stars, CNN notes.
In 2017, astronomers observed two neutron stars colliding. The cataclysmic collision produced ripples in spacetime known as gravitational waves, as well as radiation from a gamma-ray burst. The collision, known as a kilowave, also produced heavy elements such as gold, platinum, and lead. Kilon waves have been likened to gold-producing “factories” in space.
Most neutron star mergers are thought to have occurred only in the last few billion years, said study co-author Eric Burns, an associate professor and astrophysicist at Louisiana State University in Baton Rouge.
But previously murky data from 20 years ago from NASA and European Space Agency telescopes suggests that flares from magnetars that formed much earlier, during the early days of the universe, may have provided another way to make gold, Burns notes.
Neutron stars are the remnants of the cores of exploded stars, and they are so dense that on Earth, 1 teaspoon of star material would weigh 1 billion tons. Magnetars are extremely bright neutron stars with incredibly powerful magnetic fields, CNN explains.
Astronomers are still trying to figure out exactly how magnetars form, but they suspect the first magnetars likely appeared just after the first stars formed, about 200 million years after the universe formed, or about 13.6 billion years ago, Burns says.
Sometimes magnetars release huge amounts of radiation due to “starquakes.” On Earth, earthquakes occur because the Earth’s molten core causes movement in the crust, and when enough stress builds up, it causes the ground beneath your feet to move erratically, or shake. “Starquakes are like that,” Burns says.
“Neutron stars have a crust and a superfluid core,” Burns continues. “The movement beneath the surface creates stress on the surface, which can eventually cause a starquake. On magnetars, these starquakes produce very short bursts of X-rays. Just like on Earth, you have periods where a given star is particularly active, causing hundreds or thousands of flares over a period of weeks. And similarly, you have particularly powerful earthquakes from time to time.”
The researchers found evidence that the magnetar was releasing material during a giant outburst, but they had no physical explanation for the star’s mass being ejected, Patel said.
According to recent research by several co-authors of the new study, including Brian Metzger, a professor of physics at Columbia University and a senior fellow at the Flatiron Institute in New York City, it is likely that the flares heat and eject crustal material at high speeds.
“They suggested that the physical conditions of this explosive mass ejection were promising for the production of heavy elements,” Patel says.
The research team was curious to see if there might be a connection between the radiation from the magnetar flares and the formation of heavy elements. The scientists looked for evidence in visible and ultraviolet wavelengths of light. But Burns wondered whether the flare might also produce detectable gamma rays. He looked at gamma-ray data from the last observed flare from a giant magnetar, which occurred in December 2004 and was recorded by the INTEGRAL, or International Gamma-Ray Astrophysics Laboratory, mission. Astronomers had detected and characterized the signal, but at the time they didn’t know how to interpret it, Burns said.
The prediction, based on a model proposed in Metzger’s previous study, matched the signal received in 2004 exactly. The gamma rays resembled what the team had predicted would be the formation and distribution of heavy elements in a giant magnetar outburst.
Data from NASA’s retired Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Wind satellite also supported the team’s findings. Long-term studies contributed to the discovery, Burns said.
“When we initially built our model and made our predictions in December 2024, none of us knew that the signal was already in the data. And none of us could have imagined that our theoretical models would fit the data so well. It’s been a pretty exciting holiday season for all of us,” Patel said.
“It’s really cool to think that some of the elements in my phone or laptop were created by such a powerful explosion throughout the history of our galaxy.”
Dr Eleonora Troia, an associate professor at the University of Rome who led the discovery of X-rays emitted by the neutron star collision in 2017, said the evidence for the formation of heavy elements from a magnetar event was “in no way comparable to the evidence collected in 2017”.
“Gold extraction from this magnetar is a possible explanation for its gamma radiation, one of many others that are discussed candidly at the end of the paper,” Troja notes.
Dr Troya adds that magnetars are “very messy objects.” Given that gold production can be a complex process requiring special conditions, it’s possible that magnetars could add too many of the wrong ingredients to the mix, such as an excess of electrons, resulting in light metals like zirconium or silver rather than gold or uranium.
“So I wouldn’t say that a new source of gold has been discovered,” Troya says. “Rather, an alternative way of extracting it has been proposed.”
Researchers believe giant magnetar outbursts may be responsible for producing up to 10 percent of the elements heavier than iron in the Milky Way galaxy, but a future mission could provide a more precise estimate, Patel said.
The findings could feed into NASA’s Compton Spectrometer and Imager mission, or COSI, which is scheduled to launch in 2027. The wide-field gamma-ray telescope is designed to observe giant magnetar outbursts and identify elements that originate in them. The telescope could help astronomers search for other potential sources of heavy elements throughout the universe, Patel said.
