This image (hi-res version) shows the neutrino emission from the sun. Neutrinos are uncharged and massless or nearly massless particles that hardly interact at all with ordinary matter. For more than 30 years, there was a discrepancy between theory and experiment called the solar neutrino problem. To learn about the resolution of this problem, visit Nova: Hunting Solar Neutrinos, a NOVA interview with John Bahcall.
