Supernova is the deafening explosion that takes place when a star dies emitting tons of materials, like iron, cloud and dust, at 15,000 to 40,000 kilometres per second in space. A star accumulates nuclear fuel at its centre which resists the outward gravity and keeps it heated. Millions of years later which this fuel diminishes, the star starts to cool off and no longer fights with the gravity. Eventually, gravity takes the upper hand, triggering the birth of supernova.
When a star dies, it sends shockwaves catapulting its outer parts to burst. It is hard to observe who exactly are the neighbours of a supernova thanks to the blinding light it supplies, outshining everyone.
Even a single supernova can radiate more light and energy than Sun and burn for ages. To Earthlings, witnessing a supernova in the night sky is no less than a lightshow—a gala, brightest event in the sky. To scientists, explosions are important to measure their distance from Earth by calculating the amount of light they radiate into space.
Crab Nebula— Queen Bee of Supernovae
By far, the most famous supernova in the history of stellar explosions is Crab Nebula which took place in 1054 AD. Astronomers could see the burning explosion in the day sky and the rock paintings of Arizona and New Mexico predict that south-western Native Americans might well have gazed at it!
Supernova is not the only end of stars. . .
It is not mandatory for every star to burst into a dramatically tipsy supernova explosion, a few die out slowly and become white dwarfs, red giants or black dwarfs. Black hole are sometimes the final product of a supernova, such as the AT2018cow in the constellation Hercules.
List of Well-Known Supernovae
SN 1987A- Observed as early as 1987, it was brightest of the lot whose power exceeded Sun by 100,000. The brightest pinpoint in sky was best observed by people living in the Southern Hemisphere
SN2011by- A type la supernova which means a white dwarf star has exploded due to a fusion of carbon and oxygen