Neutrinos

I've mentioned these in several discussions, but I think that they need a better description.

Neutrinos are enigmatic particles that are produced by nuclear reactions in the core of stars or by beta decay of atoms. The reason they're so hard to detect is because they have very low mass and are neutral, hence the name neutrino. These particles pass right through our bodies all of the time and we never realize it. In fact, they pass right through the Earth.
First of all, a neutrino is a fermion elementary particle with a half-integer spin and a mass much lower than any other known particle. They obey the Pauli exclusion principle and operate according to Fermi-Dirac statistics.
The Pauli exclusion principle states that two particles cannot occupy the same quantum state. The Fermi-Dirac statistics has to do with half-integer spin particles that have negligible mutual interactions, statistically that is. Probability is the cornerstone of quantum physics.

As with most fermions, neutrinos come in flavors, there to be exact, and these flavors have corresponding anti particle flavors. The three flavors are electron, muon and tau. As with other fermions, they can do crazy stuff like quantum superposition in which two ore more quantum states can be added together to get another quantum state, or put another way, a quantum state can be represented as the sum of two or more quantum states. What does this mean for neutrinos? It's where a particular flavor of neutrino represents a summation of all three flavors. What it means is that a neutrino oscillates between different flavors in flight. That means that the mass can appear to change as it goes along on its merry way. It's a quarky quantum thing. Oh, and each neutrino flavor has a corresponding anti-neutrino flavor. I would call these the spicy flavors.
Here's where it gets spooky. It's possible that neutrinos can behave as if they are mass less. If this is the case, they can travel at the speed of light. It's also possible that they can exceed the speed of light.

So, what good do neutrinos do? That's also a matter of speculation, but it's believed that they carry some of the energy involved with gravity and they also carry away energy from nuclear fusion in the core of stars and when stars go supernova. The other thing that neutrinos do is help cosmologists explain why the Big Bang ended up in favor of matter instead of antimatter. This could have been the result of a tiny difference in the mass of neutrinos compared to their evil twins, anti-neutrinos.

Since neutrinos are almost without mass and not charged-unlike photons-they can emerge from deep inside stars and travel anywhere they want to without interference. They aren't defected by magnetic fields and are not absorbed by matter. That's why they're so hard to detect. Some people have described the instruments designed to detect neutrinos as butterfly nets for ghosts. The trick is to force neutrinos to leave some of their energy while passing through an enormous amount of liquid containing material (some source of chlorine such as perchloroethylene) that emits a photon when hit by an elusive particle. The reason why a liquid like this is sensitive to a particle like a neutrino is because the chlorine atom is large and this substance has four chlorine atoms per molecule. These detectors are buried as far underground as possible to avoid contamination from other radioactive sources such as cosmic rays. They are usually surrounded by lots of water, which is an excellent shield against radiation.

The reason that these ghost particles are important is that they explain a lot of what occurred at the time of the Big Bang and subsequently what happens inside stars and supernovae.

Neutrinos also could help astronomers know when a star will go supernova because a star emits a bunch of neutrinos just before it happens. This is because the core collapses immediately, but the explosion takes time to punch out through the outer layers of the star. The neutrinos formed by the core collapse fly out through the outer layers unimpeded and fly off at the speed of light, thus getting to us before the light of the supernova explosion. The trick here is to detect the neutrino blast and get the location of the supernova star to astronomers in time.

Thanks for reading.