Neutrinos are fundamental subatomic particles characterized by an extremely small (though non-zero) mass, a neutral electric charge, and a spin of 1/2. Because they interact only via the weak nuclear force and gravity, they pass through ordinary matter virtually unimpeded.  

​Key Characteristics & Role in Fusion

​Stellar Production: In the core of stars like the Sun, nuclear fusion (such as the proton-proton chain) powers the star by converting hydrogen into helium. This process releases vast quantities of electron neutrinos as a direct byproduct.  

​Unfiltered Messengers: Because photons (light) generated in the core take tens of thousands of years to diffuse through a star's dense plasma via continuous absorption and re-emission, neutrinos escape the core immediately. They stream outward at nearly the speed of light, carrying pristine data about interior core temperatures, densities, and active nuclear reactions directly to Earth.  

​Flavor Oscillation: As neutrinos travel through space and matter, they undergo quantum oscillation, shifting between three known "flavors" (electron, muon, and tau neutrinos). This phenomenon resolved historical solar neutrino puzzles and proved that neutrinos possess mass.