What is a Supernova?

A supernova is not a magged out car of questionable quality from the 70s. A supernova is an explosion of a star that is far more intense and subsequently much brighter than simple nova.  In fact, when a star goes supernova it can be so bright that it is seen from earth.  It is estimated that a star goes supernova roughly once a century and, in fact, the earliest recorded observation of this celestial event dates back to the 11^th century when astronomers in China noticed an unusually bright object appearing in the constellation known today as Cassiopeia.  (A supernova has also been forwarded as an explanation of the star heralding the birth of Christ.)  The aftereffects of the star that went supernova can still be observed today as the Crab Nebula.

Although this was the first recorded observation, it is highly likely that previous supernovas had been seen since they are so incredibly bright.  Later identifications of exploding stars were made by Tycho Brahe and Johannes Kepler.  In fact, it was the supernova recorded by Kepler and eventually named Kepler’s Star that was the last supernova to take place in the Milky Way galaxy.  Supernovas can be created in two different ways and are thus categorized as either Type I or Type II.  The Type I supernova occurs when a star known as a white dwarf accretes more hydrogen than it is capable of sustaining from its partner star.  When this happens the star gradually reaches the point of collapse and an enormous explosion occurs.  That explosion is the star going supernova.   A Type II supernova is the result of a complex series of reactions involving gases such as helium and magnesium.  The star then collapses as a result of gravitational pull on its iron core.  In the explosion created by a Type II supernova, material issues forth from the star to create a massive shock wave.  Indeed, so much energy is created by this type of supernova that they are the responsible for all the elements in the universe that are heavier than iron.

There is a star close to earth that is expected to go supernova at some point in the distant future.  The star is Betelgeuse, is not related to Michael Keaton, and is located in the constellation of Orion.  (I believe the constellation of Orion was named after the late, great movie production house of the same name, but I might be wrong.)  This supernova will be of the Type II variety and is expected to provide a sight unlike anything ever before seen from earth due to its close proximity to our planet.  In fact, scientists suggest that Betelgeuse is currently in the stage of a supernova where carbon is fusion is taking place. If that is the case, the star will explode within the next thousand years.