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Neutrinos are all around you. They are extremely light, electrically neutral particles that only rarely interact with other matter. They are made in a variety of processes in space and on Earth. Even though they are constantly streaming through us billions at a time, we never feel a thing. Yet neutrinos seem to play a crucial role in our universe and might even hold the key to explaining why matter exists.

is for neutrinos

coming in endless streams.

is for magnets, directing particle beams.

Magnets are essential for particle physics. Scientists use magnets to steer charged particles through particle accelerators. They also use them to squeeze particles into beams. The largest accelerator in the world, the Large Hadron Collider, is 17 miles long and uses more than 9000 magnets.

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Neutrinos come in three types. As they travel, they transform from one type to another. This is called oscillation. When scientists first discovered neutrinos, they noticed they were catching fewer than they expected. They found out later that the neutrinos they were looking for had simply changed into another type that they needed to detect in a different way.

is for oscillation,

when neutrinos change type.

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is for photons, which brighten the night.

Photons are particles of light. They are the fundamental particles that carry the force of electromagnetism. And they’re the most abundant particles in the universe. Photons are important in particle physics experiments; scientists can detect many types of particles by the trail of light that they leave in a detector.

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is for quarks—they come in six kinds.

Quarks are among the smallest building blocks of matter. They come in six types: up, down, charm, strange, top and bottom. Up and down quarks bind together via the strong nuclear force to form the protons and neutrons in atomic nuclei. The top quark is the heaviest elementary particle ever discovered. It weighs as much as an entire gold atom.

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