system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 - What is happening when you see 'stars'?

When you get up too fast or do a cartwheel (which I rarely do but still...)
gpt
When you stand up too fast, a temporary drip in blood pressure causes a short lack of oxygen to the nerves in your eyes, which causes a "dead signal", which looks like dark spots in a bright location or light spots in a dark location. This lack of O2 is usually short enough that there's not permanent damage.