Supernova
A supernova is the biggest explosion that humans have ever seen. Each blast is the extremely bright, super-powerful explosion of a star.
A supernova is the name given to the cataclysmic explosion of a massive star at the end of its life. It can emit more energy in a few seconds than our sun will radiate in its lifetime of billions of years. The sky above us is strewn with alluringly beautiful remnants of ancient supernovae, that is, stars that lived out their lives and then died in these violent explosions. In a galaxy like our Milky Way, consisting of some 200 billion stars, there should be a supernova as often as every 50 years. Yet supernovae visible to the eye alone are exceedingly rare. You might – or might not – witness one in your lifetime.
Learn more on Wikipedia