system
Given the following post, respond as if you're commenting on Reddit:
human
How do we know that a black dwarf star exists if it's never been seen before?
gpt
It's thought that they don't exist yet, because there hasn't been enough time for white dwarves to cool. Because white dwarves are radiating away all this energy, it is thought that eventually it will cool through this process. If that is wrong, astronomers in a trillion years can find out.