what is a neutrino?

Answer 1

Neutrinos are elementary particles. Travelling close to the speed of light, lacking electric charge and able to pass through ordinary matter almost undisturbed, their detection is extremely challenging. Neutrinos were once thought to have no mass, but they are now known to have a minuscule (but non-zero) mass.

Neutrinos are created as a result of certain types of radioactive decay or nuclear reactions such as those in the sun, in nuclear reactors, or when cosmic rays hit molecules. There are three types, or "flavors", of neutrinos: electron neutrinos, muon neutrinos and tau neutrinos; each type also has an antimatter partner, an antineutrino. Electron neutrinos or antineutrinos are involved whenever neutrons change into protons or vice versa, in the two forms of beta decay.

Most neutrinos which pass through the Earth emanate from the sun and more than 50 trillion solar electron neutrinos pass through the human body every second.

Answer 2

A neutrino is an elementary particle with very little mass and no polarity. It means that it has no charge; for example the electron has a negative polarity and the proton has a positive polarity.
Neutrinos do not easily interact with matter, so they pass through undisturbed.
They are produced as a result of nuclear reactions, such as those taking place in the Sun.
I am giving also a nice article in wikipedia which has a lot of information on the neutrino, if you want to read something further.

Answer 3

Neutrinos are produced in super nova explosions,also during the decay of neutrons.
Because of their inability to react with other matter they may be two dimensional particles which will pass through most matter due to the quantum effect,which makes them 3 dimensional for short periods.

Answer 4

I dont really know . I experimentaly have never seen one or had a concrete proof of its interaction with mass strutures. I would believe that they exist if I saw one.