Just the description given by Phil Plait is enough for me to fall in love with astronomy again. Make sure to read his entire article and enjoy the pictures.
More than 6,000 light-years from Earth, a massive star was dying.
Its core was hot chaos. The star had been fusing hydrogen into helium for millions of years before running out of fuel. Then it started fusing helium into carbon, but then ran out of this fuel in just a million years. Carbon fusion initiated, churning it into neon for a millennium, then neon into magnesium for a single year. It fused the resulting oxygen into silicon, running out in just a few months. Just the day before—a single day, after all those eons!—it began fusing silicon into iron.
And it was doomed. Iron fusion is unsustainable. In a single instant the core collapsed, unleashing a fury of energy and subatomic particles that slammed into the material above.
The star exploded.