system
Given the following post, respond as if you're commenting on Reddit:
human
When a star goes super nova, is the gold fused inside the star's core, or does the shockwave fuse matter in it's outer orbit? Neither/both?

Just wondering. You folks are great.
gpt
The "core" never really fuses gold, as the core is only ever capable of fusing up to iron, and only the heaviest stars will ever get to that point. Smaller stars like our sun can only provide enough temperature and pressure through gravity to fuse up to oxygen and carbon, and then die out as white dwarfs. As gold is significantly heavier than iron, a star's core can never produce it while it's still "alive."  


Iron is the point at which further fusion reactions require you to add energy rather than the reaction producing any. That's the point at which the core suddenly collapses and begins the supernova, because the iron is not producing energy pressure to hold up the weight of the rest of the star anymore.  


As the core collapses, unless it's so heavy that it collapses straight into a black hole, it stops and "bounces" at the point it creates a neutron star, which can hold itself up through other methods than fusion. The rebound shock wave  briefly produces energies and pressures even higher than the fusion core of the original star. This brief period is capable of fusing the rest of the elements heavier than iron on the periodic table.  


However it's funny you ask about gold, because up until now, we didn't think this brief period during a supernova was sufficient to create the amount of gold we actually see in the universe. Very recently, we observed two neutron stars orbiting and colliding into each other. This seems to create enough temperature and pressure for long enough to explain the rest of the gold out there.