For centuries, alchemists have dreamed of turning lead into gold. At the Large Hadron Collider (LHC), they’ve finally managed to do it. There were no spells and no magic elixirs. It was just high-speed lead ions, flying and nearly the speed of light and barely missing each other.
Although it lasted for only a fraction of a second, a team of physicists has now observed and measured this modern-day transmutation. This marks the first time that gold creation at the LHC has been directly quantified — and it’s changing how we think about what these collisions are capable of.
The Philosopher’s Stone
Deep beneath the Franco-Swiss border, CERN’s 27-kilometer underground ring is like a modern-day Philosopher’s Stone. This legendary alchemical substance was said to have the power to turn “ordinary” metals into gold. The LHC does much more than that.
In several experiments, it accelerated lead ions at over 99.999993% of the speed of light. Most of them smashed head-on, creating minuscule but violent fireballs that mimic the conditions of the early universe. But sometimes, when the conditions are just right, they graze past each other. This is what physicists call ultraperipheral collisions. No contact or fusion, just an insanely fast electromagnetic handshake.
These near misses unleash ultra-powerful electromagnetic fields, strong enough to emit short bursts of photons (light particles). These photons have enough energy to knock a few protons and neutrons out of atomic nuclei. This process, called electromagnetic dissociation, is what allows a lead-208 nucleus (with 82 protons) to shed just enough protons — three, to be exact — to become gold.
A chemical element is defined by how many protons its nucleus contains. Hydrogen has one. Carbon has six. Gold has 79. If you change the number of protons, you change the element itself. So when a lead atom (82 protons) loses three protons, it’s no longer lead — it is gold. This isn’t chemistry; it’s nuclear physics.
Is CERN opening a jewelry store?
During Run 2, the LHC’s second operational run that lasted from 2015 to 2018 these near-miss collisions between lead nuclei were creating about 89,000 gold atoms every second. That means, on average, a new gold nucleus was forming every 11 microseconds. In the subsequent Run 3, where energy was increased, this was increased to roughly 178,000 gold atoms per second. But a single gram of gold has around 3,057 billions billions of atoms.
That’s not even the biggest problem. These atoms were “born” at incredible speeds, embedded in a high-energy beam of particles. A fraction of a second after they were created, they smashed into matter, fragmenting into subatomic debris. Their lives were golden, but they were also short and violent. This method also costs way more than the market price of gold.
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But this achievement is important from a different perspective.
These collisions and near-collisions test the very models we use to understand how matter behaves in extreme conditions. This is useful for our basic understanding of the universe and also in designing future particle accelerator experiments. Understanding how and when nuclei lose protons helps engineers design better beam controls and avoid costly shutdowns.
Gold wasn’t the only element produced by the experiment. Thallium (81 protons) and mercury (80 protons) were also produced, and in far greater quantities than gold.
So how did they measure it?
The real achievement in this study isn’t the creation of gold atoms, it’s the precise measurement of this process.
The ALICE experiment — A Large Ion Collider Experiment — is built to study the exotic soup of subatomic particles like quarks and gluons that spill out from some crashes. But it’s also uniquely equipped to spot the subtler byproducts of non-collisions.
To catch gold being born, researchers focused on the aftermath of these glancing blows. Instead of watching for thousands of particles flying every which way, they looked for just a handful — specifically, the tiny number of protons and neutrons ejected from the nuclei.
Using detectors called Zero Degree Calorimeters (ZDCs), placed far from the main collision point, the ALICE team counted events where one, two, or three protons were knocked loose from a lead nucleus, resulting in thallium, mercury, and gold respectively.
Modern-day alchemy hits differently
After centuries of fruitless pursuit, the alchemists’ dream has come true — not in a smoky basement, but in the world’s most advanced physics lab. Not for wealth, but for knowledge.
People used to think it was magic that will get this done. But it’s science; it’s always science.
It’s unlikely these fleeting gold atoms will ever serve as currency. But what they are buying is a deeper understanding of nuclear forces and how matter behaves when pushed to its breaking point. The ability to observe such a delicate process, hidden amid trillions of high-energy events, is a triumph of experimental physics. It’s something alchemists would probably also appreciate.
