Last month, a small company in San Francisco announced that it had a plan to manufacture gold—not merely a flake or a nugget, but tons of the stuff. According to a paper written by one of Marathon Fusion’s co-founders (and not yet peer reviewed), the alchemist’s dream could be achieved not by mixing powders in a crucible but by tweaking atoms that were superheated during the process of nuclear fusion. The gold wouldn’t be the end game, more like a side hustle. The millions of dollars made from selling the precious metal could be used to offset the cost of nuclear fusion, a near-limitless power source that maybe, just maybe, could one day replace fossil fuels.
For more than two millennia, the promise of alchemy—and, specifically, transmuting ordinary elements into valuable ones—has intrigued scientists and scoundrels alike. Medieval alchemists were obsessed with finding or creating the Philosopher’s Stone, a substance thought to turn common metals into gold. That turned out to be elusive, though arcane tinkering continued for centuries. Then, in the early 1900s, physicists determined that they could change one element into another by altering the number of protons in its nucleus. In an essay published in The Atlantic in 1936, a physicist wrote that turning mercury into gold—which is what Marathon is advocating—was scientifically possible but “cannot be commercially profitable.”
That didn’t stop scientists from giving it a go. Over the past 50 years, researchers have produced gold in laboratories, but only on the scale of atoms. In 1980, Glenn Seaborg, who was part of the team that first isolated plutonium, was able to turn several thousand atoms of the metallic element bismuth into gold by using a particle accelerator. The amount was minuscule—not enough to see, much less sell—and the cost exorbitant. Seaborg estimated at the time that, using his technique, making a single ounce of gold would cost $1 quadrillion. In May, scientists reported that they had turned lead into gold inside the world’s largest particle accelerator, in Switzerland—although, again, the yield was tiny, measured in trillionths of a gram. And an instant after the gold atoms were created, they dashed themselves into subatomic particles inside the accelerator.
Nuclear fusion has proved similarly challenging, despite being pursued with similar fervor. Fusion, in which atoms are smashed together in order to release energy, is the holy grail of clean power, both because it creates less waste than fission reactors and because it doesn’t carry the same risk of melting down like the ones in Chernobyl and Fukushima. Although experimental fusion reactors that can make electricity have been built, the technology hasn’t advanced enough to allow fusion to be practical on a commercial scale. Fusion, like modern alchemy, is prohibitively expensive, in part because the reaction requires extremely high temperatures, which require a lot of energy to achieve.
Back in February, Adam Rutkowski, one of the co-founders of Marathon, started thinking about additional ways that a fusion reactor could prove useful—an extra revenue stream, perhaps, that could subsidize the costly process. He told me that he’d had a few other ideas, including one involving nuclear batteries, before he arrived at his epiphany: The neutrons produced during fusion could be repurposed to change one metal into another. A power plant, in other words, could double as a gold factory.
Rutkowski ran the idea past several fusion physicists, including Dennis Whyte, a professor of nuclear science and engineering at MIT. Whyte told me that he thought it was clever, and he plans to test the theory by using computer simulations during one of his classes next semester. Steven Cowley, the director of the Princeton Plasma Physics Laboratory, who was not involved in the study, was likewise intrigued. Rutkowski has “a really nice idea,” Cowley told me, though he would like to see more analysis before he’s entirely convinced that gold could be manufactured in this way.
At the moment, Rutkowski’s idea is entirely speculative; he’s not sitting on a pile of gold, but rather would like to be one day, as commercial fusion becomes more of a reality. In fact, the utter lack of commercial fusion in 2025 is likely the largest and most obvious barrier to his vision. Marathon is not in the reactor-building business; instead, it hopes to team up with such companies by consulting and supplying them equipment. According to a recent survey, fusion companies have raised $2.6 billion in the past year, and the majority of company representatives who responded said they believe that fusion power will become a reality at some point in the next decade. Some physicists I spoke with thought that timeline might be optimistic, but they also noted that significant progress has been made in recent years.
I sent Marathon’s proposal to Lawrence Principe, a historian and chemist at Johns Hopkins University who has written several books about alchemy and has re-created alchemical recipes in his lab. (He successfully replicated one 17th-century experiment that made a lump of gold appear to grow into a glittering tree inside a flask.) Principe was struck, while perusing the company’s website, by the spirited promotional language—touting a “golden age,” for example—that echoes the pamphleteering of centuries past. “I’m getting deja vu here looking at this relative to 16th- and 17th-century texts,” he told me.
Like Marathon, many alchemists from that era advertised that they were on the cusp of a breakthrough, according to Principe. They wrote to kings and queens asking for an investment in their laboratory, or for a gold sample to kick-start the undertaking. In the 15th century, King Henry IV banned the practice because he was worried about alchemical advances undermining gold currency. That’s a theoretical consideration today too. But fusion seems unlikely to devalue anyone’s stockpile: Rutkowski estimates that a single reactor could produce just a couple of tons of gold per year—worth more than $200 million, but still a far cry from the 3,000-plus tons that are mined annually, not to mention that any gold produced through fusion would be somewhat radioactive and would take about 15 years to be considered safe.
The history of alchemy is replete with stories of dashed hopes and dubious boasts. In 1782, a British chemist named James Price, like Marathon, claimed that he could turn mercury into gold, though he professed doing it with mysterious powders rather than nuclear energy. After being repeatedly challenged to replicate his experiment, he agreed to put on a public demonstration. But instead, when the time came, he drank a vial of poison and died in front of the three witnesses who showed up. In the early 20th century, Rudolph Hunter, an engineer and inventor, was deemed a “modern Midas” after claiming he was set to build a factory that could produce thousands of dollars’ worth of gold a day by using principles he had learned from studying the sun. He passed away before proving his concept.
Unlike those ill-fated efforts, Marathon’s plan has real science behind it. If it works, the achievement would mark the end of the alchemist’s quest, proof positive that humankind can alter the elements. But Rutkowski and company aren’t driven by the desire for gold itself. Instead, they’re after a technology that could help sate the world’s ever-growing need for energy—a prize that’s far more valuable and, for now, still just out of reach.
