Meet the strangest particle in physics in the latest episode of the Big Ideas Lab podcast

There are particles in our universe so unique and so strange that they can shift form mid-flight. They’re as old as time, coming from the beginning of the universe, stars, nuclear reactions and the earth. And they’re everywhere — even passing through you at this very second: neutrinos.

Studying these mysterious particles may unlock answers to some of humanity’s most pressing questions about matter and why the universe exists at all. Scientists at Lawrence Livermore National Laboratory (LLNL) are determined to uncover the neutrino’s secrets. Learn more about the particle and the Laboratory’s efforts to study it on the latest episode of the Big Ideas Lab, available on Apple and Spotify.

“The sun is some 90 million miles away. It's emitting so many neutrinos right now that there's a trillion per second going straight through you, and then you don't sense them because they just go straight through,” said LLNL scientist Mike Heffner. “They go through the earth and come out the other side.”

The neutrino seldom interacts with anything, slipping through our universe without a trace.

“That's one of the most distinguishing features of a neutrino compared to the other particles,” said Heffner.

It’s also what makes the particle hard to study.

LLNL is probing neutrinos on two fronts: uncovering their quantum nature and searching for heavy versions that may reshape our understanding of particle physics.

The true quantum identity of the neutrino remains unanswered. A neutrino might be similar to the familiar particles that build everyday matter. But there’s a more profound possibility that they may behave much differently, acting as their own antiparticle.

In the first moments of the universe, matter and antimatter should have balanced each other out. They should have destroyed each other, but somehow, an excess of matter survived. And we don’t know how.

Neutrinos might carry the answer, and scientists are chasing their trails to uncover why we exist at all. To accomplish this, researchers must capture evidence of an extraordinarily rare nuclear process called neutrinoless double beta decay. LLNL has been working on technology for detecting this decay since 2014 and enabling technologies years before that.

But neutrinoless double beta isn’t the only way to study neutrinos. Another theory points to a different kind of neutrino — one that carries more mass. It’s called the heavy, or sterile, neutrino because it only interacts with gravity.

“Candidates for dark matter that people have focused on for the last couple of decades include weakly interacting massive particles, or WIMPs. There are things called axions. And then there are sterile neutrinos,” said LLNL scientist Nathaniel Bowden. “So that explains why so much effort goes into searching for those three categories.”

At LLNL, scientists are tracing these elusive signals, using cutting-edge detectors to capture their rare interactions and decode the secrets they carry. Find out more about neutrinos and the efforts to study them in the latest episode of the Big Ideas Lab, available on Apple and Spotify.