Lopsided Explosions
Stars are big, hot, almost round balls of gas. Fortunately for us, though, they aren't perfect spheres. If they were, we might not be here.
That's because the iron, oxygen, silicon, and many other elements found on Earth -- and in our bodies -- are forged inside massive stars. When these stars explode as supernovae, they scatter their chemical stew into space, where it can be incorporated into new stars, planets, and people.
As astronomers began simulating how these stars work, they found that when they used stars that were perfect spheres as examples, the explosion fizzled out.
A supernova occurs when the core of a massive star collapses to form an ultradense neutron star. The surrounding layers crash toward the core, then rebound. A shock wave, driven by particles called neutrinos, begins racing through the star, but it quickly stalls. In a perfectly round star, it might remain stalled.
Nature doesn't make perfectly round stars, though -- they're always a little lopsided. Because of that, the shockwave of a collapsing star is unstable. It may cause the neutron star to spin rapidly, creating a powerful magnetic field. The field may shoot "jets" of particles along the star's poles, basically ramming a path for the shockwave to follow. Once it breaks through the inner regions, the shockwave blasts the star to bits.
One more factor may play a role in the explosion: sound. More about that tomorrow.
Script by Damond Benningfield, Copyright 2006
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