SUPERNOVA

A supernova is an extremely powerful explosion of a star. Supernovae occur at the end of a star’s life. They shine brighter than entire galaxies!

Supernovae are spectacularly destructive events. The explosion of a star releases huge amounts of energy, destroying the star in the process. However, are these supernovae bad? Not at all! In fact, without supernovae, we would not have a galaxy. Life on earth would not exist.

Approximately one supernova occurs every second. Supernovae happen more often than you might think Although they would be spectacular to look at, were these “predictable” supernovae to occur, they are thought to have little potential to affect Earth.

There are two types of supernovae – type 1 and type 2. Type 2 supernovae occur at the end of a massive star’s life. All stars emit energy by converting hydrogen into helium via nuclear fusion. Eventually, the core of a massive star converts completely from hydrogen to helium. The core will become extremely hot and emit huge amounts of pressure.

At the same time, the outer layers of the star will expand. The star becomes so massive that it’s gravitational pull is very strong. The only thing keeping the star from collapsing is the pressure generated at the core. When the fuel at the core runs out, the star collapses.

This happens very quickly. In a microsecond, the collapse will crush the core. The energy from this event causes enormous shock waves. This causes the star to explode. Material from these explosions travels as fast as 18,000 miles per second.

Type 1 supernovae occur when a white dwarf and a big star orbit closely to one another. As the white dwarf sucks matter from the big star, it gains mass. Once the white dwarf gains enough mass, it will collapse. The energy from the collapse causes the supernova.

It is estimated that a Type II supernova closer than eight parsecs (26 light-years) would destroy more than half of the Earth’s ozone layer. Type Ia supernovae are thought to be potentially the most dangerous if they occur close enough to the Earth. Because Type Ia supernovae arise from dim, common white dwarf stars, it is likely that a supernova that could affect the Earth will occur unpredictably and take place in a star system that is not well studied.