What are Neutrinos?

About Neutrinos:

• Neutrinos are tiny subatomic particles, often called 'ghost particles' because they barely interact with anything else.
• Neutrinos are, however, the most common particle in the universe. 
  • Approximately 100 trillion neutrinos pass completely harmlessly through your body every second.
• Their tendency not to interact very often with other particles makes detecting neutrinos very difficult.
• Neutrinos have no charge; they are neutral, as their name implies.
• They belong to the family of particles called leptons, which are not subject to the strong force. 
• Neutrinos don't interact at all with the strong nuclear force that binds atomic nuclei together, but they do interact with the weak force that controls radioactive decay. 
• Neutrinos come from all kinds of different sources and are often the product of heavy particles turning into lighter ones, a process called “decay.”
• Neutrinos are created by various radioactive decay, such as during a supernova, by cosmic rays striking atoms, etc.

Q1: What is radioactive decay?

Radioactive decay is the random process in which a nucleus loses energy by emitting radiation. This is usually in the form of alpha particles (Helium nuclei), beta particles (electrons or positrons), or gamma rays (high energy photons). The nucleus' energy reduces, making it more stable. In all decay processes mass, charge and lepton number are conserved.

Source: In the Heart of Supernovae, Ghost Particles Reveal New Quantum Secrets