system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] What happens to ghosts like Nearly-Headless Nick when the Earth eventually explodes or gets eaten by a red giant Sun?
gpt
Ghosts are imprints of souls on the Earth.  No Earth, nothing to imprint on.  Sometimes ghosts are cited as only being able to haunt places they've been in life.  When all those places fade into the shadows of history, so too fade the ghosts that live there.