Neutrinos

The world's first neutrino observation in a hydrogen bubble chamber. It was found Nov. 13, 1970, in this photograph from the Zero Gradient Synchrotron's 12-foot bubble chamber. The invisible neutrino strikes a proton where three particle tracks originate (lower right). The neutrino turns into a mu-meson, the long center track (extending up and left). The short track is the proton. The third track (extending down and left) is a pi-meson created by the collision. Click on image for full size (143K GIF) Image courtesy of Argonne National Laboratory

The neutrino is an extremely light particle. (You definitely couldn't weigh one on your bathroom scale!) It also has no electric charge.

Billions of neutrinos from the Sun pass through the Earth without interacting with anything (they may be passing through your hands right now!). Large detectors are actually able to find some neutrinos.

Click here for a brief history of the neutrinos.

Most of the neutrinos that reach Earth from space come from the Sun (called solar neutrinos). Neutrinos are also released when cosmic gamma rays hit the Earth's atmosphere. Other sources of neutrinos are exploding stars (supernovae), relic neutrinos (from the big bang) and nuclear power plants.

The world's first neutrino observation in a hydrogen bubble chamber. It was found Nov. 13, 1970, in this photograph from the Zero Gradient Synchrotron's 12-foot bubble chamber. The invisible neutrino strikes a proton where three particle tracks originate (lower right). The neutrino turns into a mu-meson, the long center track (extending up and left). The short track is the proton. The third track (extending down and left) is a pi-meson created by the collision. Click on image for full size (143K GIF) Image courtesy of Argonne National Laboratory

The neutrino is an extremely light particle. It has no electric charge. The neutrino interacts through the weak force. For this reason and because it is electrically neutral, neutrino interactions with matter are extremely rare.

The Sun is estimated to produce some 10³⁸ neutrinos per second (that's a lot!!). Billions of these neutrinos pass through the Earth without a single interaction (they may be passing through your hands right now!). Large and very sensitive detectors are actually able to detect neutrinos.

Click here for a brief history of the discovery of neutrinos.

Neutrinos are produced in a variety of nuclear processes: most of the neutrinos that reach Earth from space come from the Sun (called solar neutrinos). Neutrinos are also released when cosmic gamma rays hit the Earth's atmosphere. Other sources of neutrinos are exploding stars (supernovae), relic neutrinos (according to the current theory about the origin of the universe) and nuclear power plants.

The world's first neutrino observation in a hydrogen bubble chamber. It was found Nov. 13, 1970, in this photograph from the Zero Gradient Synchrotron's 12-foot bubble chamber. The invisible neutrino strikes a proton where three particle tracks originate (lower right). The neutrino turns into a mu-meson, the long center track (extending up and left). The short track is the proton. The third track (extending down and left) is a pi-meson created by the collision. Click on image for full size (143K GIF) Image courtesy of Argonne National Laboratory

The neutrino is an extremely light (and possibly massless) neutral particle. The neutrino belongs to the family of leptons, the particles that interact through the so-called weak force. For this reason and because it is electrically neutral, neutrino interactions with matter are extremely rare.

Click here for a brief history of the discovery of neutrinos.

Neutrinos are produced in a variety of nuclear processes: most of the neutrinos that reach Earth from space come from the Sun (solar neutrinos). Other sources of neutrinos are the Earth's atmosphere (neutrinos are produced in reactions triggered by cosmic gamma rays), exploding stars (supernovae), relic neutrinos (according to the current theory about the origin of the universe) and nuclear power plants.