Basic Information
A supernova (plural is supernovae) is a stellar explosion. This often happens to large stars as they near the end of their lifetime. Stars more than about 8 or 9 times as massive as our Sun are likely to undergo the supernova reaction as they prepare to burn out. In a supernova, the vast majority of the matter in the star undergoes nuclear fusion all at once. This lasts only a few weeks or months, but in that short time the supernova will emit more energy than our Sun will in its entire lifetime. Supernovas shine brighter than entire galaxies. When the supernova is done, all that will remain is a neutron star or black hole, at a new velocity and trajectory from the stars former path. There is also a shockwave and accelerated cloud of gas and dust called a supernova remnant.
Supernovas are categorized into Type I and Type II supernovas, and Type I is further subdivided into Type Ia, Ib and Ic.
- A Type Ia Supernova is when a White Dwarf Star accumulates enough stellar matter (often "stolen" from another star in its Star System) to reach a critical mass. It's different from the other types, which represent a core collapse of a much larger star. They are dangerous in that the dim star that spawns them is faint enough we might not even realize there's anything happening till it's too late.
- Only a Type Ib or Ic supernova can produce a gamma ray burst. The gamma ray burst is when the supernova ejects huge amounts of energy and matter in two narrow beams in opposite directions. These beams are terribly disruptive and can render entire planets uninhabitable in seconds. Even if the gamma ray burst that hit us was a thousand light-years away, it would destroy all life on the side of the earth facing it, and cause acid rain, flash burns and an effect like nuclear winter to devastate the other side of our planet. It is projected that there's about a 1% chance of the earth, sometime in it's entire life, being hit by a gamma-ray burst.
Supernova's appear to occur about once every 50 years or so in an average galaxy about the size of the Milky Way. Looking out on the entire Universe, our observatories and telescopes can detect about 3 supernovae per day. Supernovae are believed to be a major factor in the evolution of new Star Systems and Planetary Systems. The shockwave can ignite stellar combustion, and the supernova reaction fuses light elements into heavy metals and then propels them out into the universe. Those substances enrich the planets that eventually form around the new stars the shockwave started.
Though they have a similar name and both involve a star getting brighter, a supernova is caused by completely different factors than a Nova.
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Game and Story Use
- Terribly destructive, supernovas are a huge threat you can use for an interstellar disaster genre scenario. They can obliterate planets hundreds or thousands of light years away.
- They may be the cause of Interstellar War - if say, the home world of a major Space Empire was wiped out by a gamma ray burst, and many of the colonies devastated by a near miss… You'd end up with desperate survivors on planets suffering ecological collapse, refugees in space, and a former empire that was now a tempting target.
- Technology to provoke a supernova reaction would be the ultimate Weapon of Mass Destruction.
- The video game Weird Wars: Return To Infinite Space has an evil alien race that can do exactly that.
- The most likely future natural Supernova to destroy the earth is IK Pegasi, a binary star that includes a white dwarf well on it's way towards accumulating the matter needed for a Type Ia explosion. Don't worry though, it might still take it millions of years to get to that stage.
- A blast wouldn't even have to hit an inhabited world to cause destruction - it could just put enough pressure to make a nearby gas giant ignite, and the good planet (which was never hit) would bake under the increased light and heat.