A supernova is a cataclysmic ending to the life of a large star. The reason these stars explode (supernova) is due to the fact they are too large to sustain equilibrium for very long. Our Sun is calm middle sized star that should last 5 billion more years or so. Massive stars lifespans can be measured in millions of years.
Well recently we’ve witnessed a star going supernova. One scientist compared it to winning the lottery. I’d say it’s probably more probable to win the lottery. People win lotteries every week! We’ve only ever witnessed a supernova the moment it happened just this once, so far.
NASA’s Swift satellite caught the exploding star in action. As stated in the article, we’re used to seeing stars after they explode, never the moment they do explode. A comparison the article makes is it would be like seeing fireworks a couple of seconds after exploding. It’s still cool to see but, if astronomers are anything like me, they like things that go BOOM!
Why do large stars supernova?
Long story short:
Huge stars burn their fuel at an amazing rate. This fuel is what keeps stars in equilibrium. This means that the outward force of nuclear fusion reactions is equal to the inward force of gravity. One tries to blow it up, the other tries to crunch it down.
It looks something like this:
>>>><<<omg it’s hot in here>>><<<<
(like my diagram?)
As a massive star runs low on fuel the inward force overpowers the outward force. Once the balance is lost, the star collapses. Once the collapse begins an unstoppable chain reaction occurs that rips the star apart in spectacular fashion. The star is blown apart and it’s outer layes are hurled into space. Whatever is left of the interior might possibly become a neutron star or a black hole, depending on the original mass of the star.