Over in this thread Why doesn’t the sun just explode all at once? I was explaining the lifecycle of our sun.
It made me wonder where our sun (or future suns) get their hydrogen from in the first place. As I understand it our sun is probably a third generation star. That is some star in the distant past formed, exploded, formed again, exploded again and from those remnants our solar system formed.
However, if a star eats all (or nearly all) its hydrogen over the course of its life where did our sun get its hydrogen from? Where will future stars get their hydrgen from? Will all the galaxies in the universe snuff themselves out as stars no longer have any fuel to grab to form? I realize there is some hydrogen left in the universe that isn’t in stars (such as hydrogen right here on earth) but our sun comprises well over 99% of the mass of our solar system (all mass) so it doesn’t seem there is enough hydrogen lying about to make an entirely new sun.
What am I missing?