The video is subtle. A small, regular chip of stonelike material as wide as the end of a ballpoint pen rests on a flat metal surface. But it’s not resting, exactly: While one end touches the metal, the other end floats above the surface, and when pushed it bobs like a cork. It’s levitating.
If the physical scale of the phenomenon was small, the response by science enthusiasts was anything but. “Today might have seen the biggest physics discovery of my lifetime. I don’t think people fully grasp the implications,” a former Princeton physics undergraduate named Alex Kaplan tweeted. The tweet has since been viewed 30 million times.
The video was attached to one of a pair of papers published by a team of researchers from South Korea on July 22 on the Arxiv preprint server, a site where scientists can post papers that haven’t yet been through the peer-review vetting process. They described the results of experiments conducted with LK-99, a lab-made substance containing lead, oxygen, phosphorus, and sulfur. (The name derives from the initials of its inventors and the year they created it.) The levitation could be explained by the Meissner effect, a characteristic of materials that are superconducting, meaning they carry electrical current without any resistance. The authors made no bones about what they thought they’d found, titling one of their reports “The First Room-Temperature Ambient-Pressure Superconductor.” This was no modest claim; scientists have spent decades searching for a substance that is superconducting under normal, day-to-day conditions, and finding one would have a revolutionary impact on a wide range of industries. “Our new development will be a brand-new historical event that opens a new era for humankind,” the authors concluded.
The story spread far and wide, from Twitter, Tik Tok, and Twitch to everymainstream publication. One of the science influencers touting LK-99’s incredible potential was San Francisco–based applied physicist Andrew Cote, who tweeted, “if successful LK-99 would be a watershed moment for humanity easily on-par with invention of the transistor.” His tweets, too, received millions of views.
As the news spread, so did optimism. For a time, one online betting market was posting better-than-even odds that the superconductor claims would pan out.
But would the findings prove replicable?
Among working physicists and chemists, the mood was muted. “The scientific community is careful,” says Leslie Schoop, a professor of chemistry at Princeton. “They’re intrigued by what’s going on, but I think that very few people actually think it could be room-temperature superconductivity.”
Superconductivity is a property of matter that can only be explained by quantum mechanics, the deeply weird “new physics” whose elucidation was portrayed in the movie Oppenheimer. This kind of material has zero electrical resistance, meaning that if you induce a current to flow, it will keep on going forever. The first superconducting material was discovered in 1911, but to work it had to be cooled to negative 452 degrees Fahrenheit. Today, science has identified superconductors that operate at temperatures as warm as 95 degrees below zero, but only if they are held at extremely high pressures.
Despite these limitations, superconductors already have practical applications. A 17-mile loop of superconducting magnets herds subatomic particles at the Large Hadron Collider near Geneva, and in Japan passengers can ride an experimental maglev train that runs along 25 miles of track at speeds of up to 375 miles per hour. But both of these require heavy infrastructure to keep the magnets cold. A superconductor that could operate at room temperature and pressure would be practical for a much wider variety of applications, including hypothetical fusion reactors creating abundant, clean energy and quantum computers capable of performing calculations that are virtually impossible using conventional processors. Lossless electricity transmission would make it a lot easier to connect cities to cheap renewable energy from far-off sources.
Numerous claims of room-temperature superconductivity have been made in recent years, but none has so far stood up to scrutiny. LK-99 seemed more promising. After the Arxiv preprints were published, multiple teams around the world raced to replicate the findings by making samples of their own. Two teams were unsuccessful, but on August 1, Chinese researchers posted a video of a fleck of LK-99 material that they had created. The tiny speck, barely large enough to be visible, seemed to float above a magnet. Meanwhile, on July 31 a researcher at the Lawrence Berkeley National Laboratory in California published a preprint on Arxiv asserting that theoretical calculations suggested that LK-99 might well be capable of exhibiting superconductivity.
Nevertheless, there were grounds for caution. The findings had been released as preprints, meaning they hadn’t passed peer review — an important mechanism to filter low-quality research from high-quality research. And there were other reasons to be skeptical. Physicists who work with superconductivity point out that superconductivity isn’t the only way that materials can levitate in a magnetic field; there are plenty of substances that exhibit this property, called diamagnetism, including some that are used in desk toys. If LK-99 is a superconductor at room temperature, it will exhibit not only the Meissner effect and zero electrical resistance, but also a number of other characteristics. So far, these haven’t been verified. And while the Chinese team found that their sample was superconductive, it turned out that this was the case only at temperatures of hundreds of degrees below zero. (This means that the diamagnetism demonstrated in their video must have been due to characteristics other than superconductivity.) This doesn’t mean the case is closed; it’s possible, for instance, that their sample was impure or improperly formulated, and that a more refined sample would perform better.
As the week went on and strong confirmatory evidence failed to materialize, the online vibe seemed to wane, and the betting markets resumed their previous pessimism. “I don’t think there is anything to this, science-wise, in terms of it being a superconductor,” says N. Peter Armitage, a professor of physics at Johns Hopkins. “Historically, there have been many, many reports of room-temperature superconductivity, but none have ever panned out. But I think it’s important to have other groups independently investigate these claims, considering the potential impact.”
What Armitage finds most interesting about the story, he says, is “the story itself — it’s interesting how such a tentative report has galvanized public imagination.”
Schoop agrees. “There is a lot of hype on social media that distorts the entire discussion,” she says. “There are a few science influencers who come up with, like, ‘This is going to change the world.’ And I think it’s just way too early to say that.”
Whatever properties LK-99 turns out to possess, its story so far is a reminder of why science is normally done in a slow, laborious way, with researchers carefully checking their work and running it by peers before unveiling it to the general public. Otherwise, the narrative is apt to get swept away by people who lack an expert perspective on what’s going on.
But ultimately, Schoop says, responsibility for the social-media frenzy lies with the authors of the LK-99 papers. “They should not have titled their preprint ‘The First Room-Temperature Ambient-Pressure Superconductor,’” says Schoop. “That’s on them.”
This article orginally ran in New York magazine on August 5, 2023.