How do neutrino detectors help study the sun today?
Today, experiments like Super-Kamiokande and its successor, Hyper-Kamiokande, continue to monitor solar neutrinos in real time. These neutrinos are produced by nuclear fusion in the Sun's core and reach Earth without scattering, providing a direct probe of the Sun's interior—something light cannot do. By measuring the flux and energy spectrum of solar neutrinos, we can test models of stellar fusion and study the Sun's temperature and density profile. For example, the 'pep' and 'CNO cycle' neutrinos, which we have recently detected, confirm that the Sun's energy comes primarily from the proton-proton chain but also from the carbon-nitrogen-oxygen cycle. This is a beautiful example of how patience and precision allow us to listen to the whispers of the universe, revealing the very engine that powers our star.
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