What is a Supernova?

About Supernova:

• It is the name given to the cataclysmic explosion of a massive star.
• Supernovas are the largest explosions that take place in space.
• A star can go supernova in one of two ways:
  • Type I supernova: A star accumulates matter from a nearby neighbour until a runaway nuclear reaction ignites. They're typically called Type Ia supernovae.  
  • Type II supernova: A star runs out of nuclear fuel and collapses under its own gravity.
• Supernovas can briefly outshine entire galaxiesand radiate more energy than our sun will in its entire lifetime.
• They're also the primary source of heavy elements in the universe.
• On average, a supernova will occur once every 50 years in a galaxy the size of the Milky Way.
• The oldest recorded supernova is RCW 86, which Chinese astronomers spotted in A.D. 185. 
• After a supernova, a few different things can happen.  
  • Sometimes the exploded star will partially collapse into a black hole or a neutron star and the rest of the mass will get converted into energy or will be blown away by the force of the explosion.  
    • This blown-away material is sometimes called a "supernova remnant," which is a type of nebula.  
  • Sometimes, if the exploded star is very massive, during the supernova, a long gamma-ray burst can also happen.  
    • Some of the shed material will get spun up around the resultant black hole or a neutron star and then get sent out through a jet at speeds close to the speed of light.  
    • Because the material is moving so fast, it can emit photons at very high gamma-ray energies—this is the gamma-ray burst.