hyper kamiokande

Neutrinos are nearly elusive particles that pass through Earth without noticing it. But sometimes one slams into an atomic nucleus in water, and a whole shower of particles is born: muons, protons, pions. Catching that moment is like photographing a bullet hitting an apple from a kilometer away.

The universe is constantly sending us signals, but many are too faint to notice. Relic neutrinos, particles left over from the Big Bang, pass through Earth by the billions every second, yet catching even one is a feat on the edge of possibility. We need a detector that can sense energy a thousand times smaller than what it takes to move a speck of dust.

Measuring distances in the universe is no easy task. Almost all methods rely on light, which can be absorbed by dust, scattered, or distorted along the way. It's like trying to spot a distant lighthouse through fog and haze. Neutrinos are a different story. These ghostly particles pass through anything without noticing obstacles.

High in the mountains, where the air is clear and still, physicists are preparing to catch elusive visitors from space — neutrinos. These particles, like ghosts, pass straight through the Earth, leaving almost no trace. But occasionally a neutrino does slam into an atom, producing a shower of particles that can be seen.

A huge pool of clear liquid is hidden deep underground. Inside, there is nothing but a pristine 'broth' that flashes with faint light when an invisible particle flies through. This is the JUNO detector—20,000 tons of liquid scintillator built to hunt for neutrinos. The main enemy of such a hunt is not darkness but its own noise.

The 21-kilometer ring near Protvino was once planned to accelerate protons. Today, the same tunnel could host a very different machine — a muon collider. The muon is a heavy cousin of the electron, and that's its strength. On a curve, an electron radiates like a searchlight, losing precious energy. A muon radiates a billion times less.

Deep inside a neutron star, matter is squeezed so tightly that familiar protons and neutrons give way to new players. Hyperons are born there — particles that harbor a strange quark.

When a massive star runs out of fuel, its core collapses, giving birth to a supernova and unleashing an all-penetrating shower of neutrinos.

Engineers create an alloy for solar concentrators by adding hard particles — like raisins in dough, to help it hold its shape under extreme heat. Too big a raisin and the material cracks. Previously, scientists manually counted these particles on microscope images.

In the depths of the ocean, where light never reaches, a plan is taking shape to capture particles that barely interact with anything. Geoneutrinos, tiny messengers from the scorching mantle, are emitted during the decay of uranium and thorium. Their flux carries information about how much heat lies hidden beneath our feet.

When a massive star dies, its core collapses, and a supernova explosion occurs. The cataclysm births streams of particles — like ripples from a thrown stone. The first to arrive are swift neutrinos, which pierce the Earth, hardly interacting. Then, hours later, ghost particles with a tiny charge appear.

Neutrinos are often compared to a radio broadcast picked up by different receivers. One station sends a signal, but antennas in Japan, Antarctica, and at the bottom of the Mediterranean Sea hear it differently — due to distance, interference, and antenna orientation.

An old photograph taken at the moment of the universe's birth has been carrying its light to us for nearly 14 billion years. This snapshot is the cosmic microwave background, the cooled echo of the Big Bang. It captures the tiny inhomogeneities from which galaxies later grew.

Somewhere in the galactic bulge, a massive star lies dormant, ready to trade quiet burning for collapse. Its core will exhaust its fuel, and in a fraction of a second, a neutron star or black hole will be born, releasing 10⁵⁸ neutrinos — almost all the energy of the explosion.

A photographer shoots a night forest, trying to catch fireflies in the frame. The flashes are rare and faint, while around there's the noise of wind and distant lights.

Deep underground in Japan, a huge tank of ultrapure water waits for rare visitors — neutrinos arriving from distant stellar explosions. Such guests are few and far between: over years of observation, Super-Kamiokande registers only a handful of events.

A giant tank of ultrapure water sits deep underground in Japan. Its walls are lined with thousands of light-sensitive sensors that catch faint flashes — the traces of ghostly particles passing through the water.

An invisible fence blocks the strait. You can't climb over it or dive under it: it's not made of steel, but of a stream of particles penetrating the water column. That's one way to describe the idea of detecting nuclear submarines by their antineutrino emission.

Deep in the Mediterranean Sea, where water presses down with the force of hundreds of atmospheres, a network of light-sensitive spheres waited for a rare guest. And it came — a neutrino that carried through the bulk of the Earth an energy comparable to the impact of a flying brick.

A translator halfway across the hall suddenly starts rendering the message backwards. That's roughly how a neutrino, a ghost particle that barely notices matter, might behave if it encounters a cloud of ultralight dark matter.

The speed of light in a vacuum is physics' metronome: it sets the rhythm for all processes. If it falters, the familiar harmony collapses. Neutrinos, ubiquitous but almost intangible particles from space, can check if this rhythm ever stumbles under extreme conditions.

A giant sphere filled with liquid flashes when an elusive particle, a neutrino, flies through it. Inside the sphere, like fireflies on a Christmas tree, hang thousands of tubes that catch these flashes. To pinpoint exactly where the flash occurred and how much energy arrived, you need to know the position of each tube to within a millimeter.

Inside every atom lives a proton. For a long time, it was considered as eternal as matter itself. But theories that unify all forces of nature predict that, sooner or later, the proton will decay. The only question is how long we have to wait. In the Japanese detector Super-Kamiokande — a giant tank of ultra-pure water — physicists searched for signs of such a decay.

Deep beneath Japan's Mount Ikeno sits a tank holding 50,000 tons of the purest water. Inside, it catches neutrinos — ghostly particles that zip through Earth as if it weren't there. When a star explodes in our galaxy, neutrinos arrive first, hours before the light.

Neutrinos are tiny particles that pass through the planet's bulk like light through a windowpane. Every second, billions of them fly through your pinky fingernail, but catching even one is no easy feat. To do it, scientists dug a two-kilometer-deep mine in Canada and installed the SNO+ detector.

Deep beneath our feet, within the planet's bulk, radioactive elements are slowly decaying. This process spawns tiny particles — geoneutrinos. They pass through the crust, mantle, and core, barely interacting with anything.

Plain water in a glass is clear and calm. But if you add tiny carbon dots made from sugar and citric acid in an ordinary microwave, the water starts to glow when a charged particle flies through it.

Radioactive tritium decays, emitting an electron. Its energy is almost always the same, but sometimes, just a little less. This shortfall could mean that alongside the ordinary neutrino, another, hidden particle was born. The Standard Model describes three types of neutrinos, but scientists suspect there is a fourth — the sterile one.

Neutrinos — elementary particles rightly dubbed “ghosts”—barely interact with matter, making their detection a formidable challenge. The existence of neutrinos was predicted by Wolfgang Pauli, and the name was coined by Enrico Fermi.

In a dark tank holding thirty tons of water, the liquid glows when a ghostly particle streaks through. Neutrinos barely interact with matter, but occasionally they bump into atoms, and a flash is born. To catch it, a special substance, a liquid scintillator, is added to the water to amplify the light.

A tiny ghostly particle zips through a piece of germanium. Usually it leaves no trace, but sometimes, like a billiard ball, it smacks into an atom's nucleus. The nucleus recoils, and that jolt can be detected. At Oak Ridge National Laboratory, the Ge-Mini detector caught such recoils for two years. Neutrinos are the most elusive of known particles.

Deep within the Antarctic ice, at depths where sunlight never reaches, antennas hang suspended. They listen not for sounds but for radio waves, waiting for a signal from a particle that is nearly impossible to catch. A neutrino passes through the Earth like a bullet through fog, but occasionally, very rarely, it grazes an ice atom.

In April 2023, Japanese satellites detected a super-intense X-ray burst on the neutron star MAXI J1752–457. The star cooled down in 4 days — five times faster than usual. Like someone cracked open a cosmic window.

A bullet that doesn't just pierce one target but leaves marks in several layers of armor. That's roughly how superheavy dark matter behaves, and it's what the DarkSide-50 detector was built to catch for the first time. The usual suspects for dark matter (weakly interacting massive particles, or WIMPs) pass through matter almost unnoticed, occasionally bumping into a nucleus.

In a vast, dark hall, they're searching for a single person who makes almost no sound. That's how physicists hunt for sterile neutrinos — ghostly particles that pass through matter, leaving barely a trace.

Cosmic particles with energies millions of times greater than anything our accelerators can produce slam into the atmosphere and create a shower of secondary particles. This shower emits radio waves that antennas on the ground pick up. But the signal is weak: it's swamped by the radio noise of our galaxy and the receivers' own noise.

In an underground hall at Fermilab, a huge tank holds liquid argon — a transparent fluid at minus 186 degrees. When an invisible neutrino flies into the tank, it occasionally strikes an argon nucleus, and a short track of charged particles flashes.

In a field stands a tank of water that usually catches particles from space. Now it keeps an eye on how much moisture is in the soil underfoot. The water in the tank acts as a trap for neutrons — tiny particles that fly out of the soil when cosmic rays hit it. The drier the ground, the more neutrons escape, and the more often the tank registers them.

In a tank of pure water, particles traveling faster than light in that medium leave bluish flashes, like a plane breaking the sound barrier creates a sonic boom. From these flashes, you can tell what kind of visitor passed through: a gamma quantum or a neutron. This is no idle task: at borders and warehouses, you need to quickly distinguish a harmless radioactive cargo from weapon-usable material.

Deep inside a dying star eight times heavier than the Sun, a quiet fever begins a few days before the final explosion. The star's core contracts and heats up, releasing neutrinos — tiny particles that barely interact with matter. This stream is like a faint whisper before a loud cry: the supernova hasn't flashed yet, but it's already sending a signal of its imminent demise.