system
Given the following post, respond as if you're commenting on Reddit:
human
Since a star has used up its hydrogen before it goes supernova, how does the resulting gasses give birth to new stars?

Wouldn't there be a lack of hydrogen to start a fusion reaction?
gpt
A star doesn't use up all of the hydrogen in the whole star, only the material in the core can fuse. The outer layers of the star, containing most of the mass, aren't burned. Some mixing can occur by convection as the star ages, but for the most part the composition of the core will be very different than the composition of the outer envelope. The hydrogen in the outer envelope isn't burned, so when the supernova happens it seeds the area nearby with not only the metals in the core but with the hydrogen and helium that still make up the vast majority of the mass of the star.