Antimatter exists in more places than most people expect. It forms naturally above thunderstorms, orbits Earth trapped in magnetic fields, streams through space as cosmic rays, and is even produced inside hospital imaging machines. While the universe is overwhelmingly made of ordinary matter, small quantities of antimatter are constantly being created and destroyed all around us.
Above Thunderstorms
One of the most surprising places antimatter turns up is right here on Earth, generated by lightning. Powerful thunderstorms act like enormous particle accelerators, producing intense bursts of gamma rays called terrestrial gamma-ray flashes (TGFs). When these gamma rays pass close to the nuclei of atoms in the atmosphere, they convert into pairs of particles: an electron and its antimatter counterpart, a positron. Scientists now think most TGFs produce these antimatter beams.
NASA’s Fermi Gamma-ray Space Telescope confirmed this in dramatic fashion. On December 14, 2009, while flying over Egypt, the spacecraft intercepted a positron beam launched upward by a thunderstorm that was actually beyond Fermi’s horizon. The onboard detector picked up the telltale signal of positrons annihilating against the spacecraft’s own atoms. Even more striking, some of the particles bounced off a magnetic “mirror point” in Earth’s magnetic field and came back, hitting the detector a second time.
Trapped in Earth’s Radiation Belts
Earth’s magnetic field doesn’t just deflect antimatter. It catches and stores it. High-energy cosmic rays constantly slam into the thin upper atmosphere, and when a cosmic ray proton has enough energy (above roughly 6 billion electron volts), it can produce antiprotons through collisions with atmospheric atoms. Some of these antiprotons become trapped in the magnetic field, spiraling along field lines in belts that mirror the well-known Van Allen radiation belts of ordinary protons and electrons.
Simulations show that the antiproton concentration inside these belts is 6 to 60 times higher than what you’d find drifting through interplanetary space, depending on solar activity. The particles spread outward from where they’re born through a slow diffusion process, filling a wider region of the inner magnetosphere over time. It’s a tiny amount of antimatter by any practical standard, but it represents the largest known natural reservoir of antiprotons near Earth.
In Cosmic Rays
Beyond Earth, antimatter is a regular ingredient in the cosmic rays that fill interstellar space. Positrons (the antimatter version of electrons) are produced when cosmic rays collide with interstellar gas, and possibly by more exotic sources like pulsars or dark matter annihilation.
The Alpha Magnetic Spectrometer (AMS-02), mounted on the International Space Station, has measured the positron content of cosmic rays with extraordinary precision, cataloging 6.8 million positron and electron events. Its data revealed something unexpected: the fraction of positrons in cosmic rays steadily increases at energies between 10 and about 250 billion electron volts, a pattern that doesn’t match simple predictions from cosmic ray collisions alone. The AMS team described this as evidence of “new physical phenomena,” and the source of these extra positrons remains an open question in physics.
Inside Medical Scanners
If you’ve ever had a PET scan, antimatter was at work inside your body. PET stands for positron emission tomography. A radioactive tracer, most commonly a glucose molecule tagged with fluorine-18, is injected into the bloodstream. As the tracer decays, it emits positrons. Each positron almost immediately collides with a nearby electron, and the two annihilate each other, producing a pair of gamma rays that fly off in opposite directions. Detectors surrounding the body catch those gamma rays and use them to build a detailed map of metabolic activity, which is why PET scans are so useful for spotting cancers and evaluating brain function.
Other isotopes used in PET imaging include oxygen-15, carbon-11, and nitrogen-13, all of which produce positrons as they decay. In this sense, hospitals routinely create and use antimatter on a daily basis.
In Particle Physics Labs
The most concentrated antimatter on Earth is made deliberately at facilities like CERN in Geneva. Researchers there have created entire atoms of antihydrogen, each one consisting of an antiproton orbited by a positron. Keeping these atoms from touching ordinary matter (which would instantly destroy them) requires suspending them in powerful magnetic traps inside ultra-high vacuum chambers.
The ALPHA experiment at CERN has pushed storage times remarkably far. Using machine learning analysis on more than 1,000 trapped antihydrogen atoms, the team established a preliminary lower limit for their confinement lifetime of 66 hours. That’s nearly three days of keeping antimatter intact, a feat that would have seemed impossible just a couple of decades ago. These stored atoms allow physicists to study antimatter’s properties in detail, testing whether it behaves as a perfect mirror image of matter or shows subtle differences.
Why There Isn’t More of It
The deeper puzzle behind all of this is why antimatter is so rare in the first place. The Big Bang should have produced exactly equal amounts of matter and antimatter, and when those equal amounts met, they should have annihilated completely, leaving nothing behind but energy. No stars, no planets, no people. Instead, roughly one particle of matter per billion survived the annihilation. That tiny imbalance is the reason anything exists at all.
Experiments over the past few decades have confirmed that the laws of physics don’t treat matter and antimatter with perfect symmetry. Certain particles that naturally oscillate between matter and antimatter states show a slight preference for decaying into matter. But the known asymmetries are far too small to explain the overwhelming dominance of matter in the observable universe. Something else, some unknown mechanism in the early universe, tipped the balance. Identifying that mechanism remains one of the biggest unsolved problems in physics.
Why Antimatter Releases So Much Energy
When antimatter meets matter, 100% of both particles’ mass converts into energy. This makes antimatter annihilation the most energy-dense reaction known. One kilogram of antimatter annihilating with one kilogram of matter releases about 90 quadrillion joules, roughly 2,000 times the energy of the same mass of nuclear fuel. About 70% of that energy could theoretically be captured for propulsion, which is why antimatter drives are a staple of science fiction.
In practice, though, producing antimatter consumes vastly more energy than it releases. Every antiproton made at CERN costs millions of times more energy than it stores. The total amount of antimatter ever produced by humans, if annihilated all at once, wouldn’t be enough to boil a cup of coffee. For now, antimatter’s value lies in what it teaches us about the universe, not as a practical energy source.