system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how we know that the universe will die and no new stars will form?
gpt
Stars are made from certain elements.  They have to also be collected into nebula.  This can't go on forever.  In fact, by looking at star formation in the past and star formation now scientists can see that star formation is really low now.  Most stars to ever exist already have.