Here's why:
* Massive Stars: Stars with a mass significantly greater than our Sun (typically 8 times or more).
* Fusion Process: Massive stars burn through their hydrogen fuel much faster than smaller stars. This leads to a rapid progression through various fusion stages, forming heavier elements like helium, carbon, oxygen, and even iron.
* Iron Core: Eventually, a massive star forms an iron core. Iron is the most stable element, meaning it doesn't release energy when it fuses.
* Gravitational Collapse: The iron core can't support itself against gravity. This leads to a rapid and catastrophic collapse.
* Supernova Explosion: The collapse triggers a shock wave that explodes outward, releasing an immense amount of energy and creating a supernova. This explosion scatters heavy elements into space, enriching the interstellar medium.
Note: The remnants of a supernova can be either a neutron star or a black hole, depending on the star's initial mass.
