Why is iron significant to understanding how a supernova occurs?
A) Iron cannot release energy either by fission or fusion.
B) Iron is the heaviest of all atomic nuclei, and thus no heavier elements can be made.
C) Supernovae often leave behind neutron stars, which are made mostly of iron.
D) The fusion of iron into uranium is the reaction that drives a supernova explosion.

Question

Quizplus · Accepted Answer

Iron cannot release energy either by fission or fusion, which means that once a star has produced a core of iron, it cannot fuse it into heavier elements to produce energy. This lack of energy production in the core leads to the collapse and explosion of the star as a supernova.

Answer: B
 Iron is the heaviest element that can be produced in a fusion reaction within a star. Any heavier elements must be made during the massive explosion of a supernova.

Answer: D
 The fusion of iron into uranium is not the reaction that drives a supernova explosion. Instead, the lack of energy production from iron in the core of a star leads to a rapid collapse and the creation of a shock wave that triggers the explosive supernova event.

Why Is Iron Significant to Understanding How a Supernova Occurs