system
Given the following post, respond as if you're commenting on Reddit:
human
If a star explodes because it ran out of fusion fuel how can it be that a new star can form out of the gas that the supernova leaves behind?
gpt
The star doesn't run out of fusion fuel. Eventually the core of the star becomes too heavy to continue fusion, but there are shells of helium and hydrogen around the core that are still burning. However, when the core stops burning in giant stars, there isn't enough pressure to prevent gravitational collapse, which causes a chain of events that leads to the supernova.