Neutrinos rank among the most mysterious particles in the standard model, largely because they are so elusive. Although around 400 trillion of them stream through every human body each second, produced mainly by the Sun, they almost never interact with ordinary matter—making them notoriously difficult to study.
A Giant Leap in Detection
To peel back some of that mystery, a massive new neutrino observatory in China has started collecting data. Scientists expect it to detect between 40 and 60 neutrinos daily over the next decade.
The facility, called the Jiangmen Underground Neutrino Observatory (JUNO), sits between two large nuclear power plants at Yangjian and Taishan. These reactors produce additional artificial neutrinos alongside the solar ones, flooding the region with particles that scarcely interact with anything around them.
Shielded Underground
Like most neutrino detectors, JUNO lies far below the surface—about 700 meters underground. The surrounding rock shields it from most other cosmic particles, such as muons, just as similar setups like IceCube rely on natural barriers to filter background noise.
To further reduce interference, JUNO uses a secondary system known as the “Top Tracker.” This setup covers a 44-meter-wide pool of ultrapure water, registering stray particles that manage to reach the site. While it cannot prevent those particles from arriving, it helps researchers rule out the false signals they create.
At the heart of the observatory sits a liquid scintillator sphere encased in more than 43,000 ultra-sensitive photodetectors, each capable of spotting individual photons. By combining signals from all detectors, scientists can extract detailed information about neutrinos, including the distinctions among the three known “flavors”: electron, muon, and tau.
Unraveling Oscillations and Mass Hierarchy
These types are known to differ slightly and, remarkably, to transform into one another—a phenomenon called oscillation. JUNO’s key objectives include unraveling the relative masses of the three neutrino types and studying how often they switch states. Determining whether one type is heavier or lighter than the others could be a major step forward.
Unlocking neutrino behavior could reshape multiple fields: cosmology, where neutrinos may have influenced the universe’s early expansion; astrophysics, where they provide clues to supernova explosions; and even geology, since radioactive decay within Earth produces them as well.
JUNO represents the latest milestone in this global pursuit. The project brings together 74 institutions and roughly 700 researchers under the leadership of the Chinese Academy of Sciences’ Institute of High Energy Physics.
Planned to operate for at least 10 years, the detector aims to amass a dataset robust enough to reveal new details about these elusive particles. If successful, the insights could ripple across many areas of science.
Read th eoriginal article on: Science Alert
Read more: Neutrinos Transform the Universe: Researchers Validate the Theory