All visible matter in the universe – stars, planets, you, me – is made up of some combination of 12 fundamental particles. The lightest and most abundant of these are neutrinos. They are also the least visible. With every tick of the clock, more than 100 billion of these “little neutral ones” stealthily zip through you, with energies so low that they leave no trace of their passage.

Neutrinos have uniquely small masses and the ability to penetrate just about anything, which make them a razor-sharp tool for physicists like me to study how fundamental particles interact with one another. For example, neutrinos may give researchers their best shot at learning why the universe is predominantly made of matter, rather than equal parts matter and antimatter.

Their unusual properties also make neutrinos fiendishly difficult to detect. Physicists have risen to meet this challenge by employing specialized materials at industrial scales. The 2026 Nobel Prize in physics went to physicist Francis Halzen for his work on the IceCube Neutrino Observatory, a detector located at the South Pole that is one of the longest-running experiments using massive amounts of material to try and catch a glimpse of these fleeting, tiny particles.

Scientists first proposed the existence of neutrinos in 1930, but it took another quarter-century for physicists to discover them. They did so using 10 tons of liquid placed near a nuclear reactor core. They detected the faint whisper of energetic neutrinos emerging from the process of nuclear fission as they collided with particles in the liquid. The first neutrino-related Nobel Prize was awarded in 1995 for this discovery.

Since then, researchers have won Nobel Prizes for discoveries using neutrinos created with particle accelerators, in cosmic-ray air showers in the Earth’s atmosphere and in the core of the Sun. The 2026 Nobel Prize in physics was awarded for the detection of neutrinos created in astrophysical sources, far away from the solar system. Many of the neutrinos used in these discoveries traversed the entire Earth before being detected.

Neutrino oscillations

Neutrinos........

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