system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] How much of the universe did The Empire control?

I know Star Wars is set in a galaxy, rather than the entire universe, but it got me wondering how much of the universe/galaxy did the empire actually control, taking real life and there are an estimated 100 billion planets in our galaxy alone, I imagine the empire in star wars could only control a few million at most and even that many seems like too much to be under the control of one man (The Emperor). 

Have other galaxies ever been explored within the Star Wars universe or is it all set in the same galaxy?
gpt
Star Wars in set in only one galaxy. Other galaxies aren't mentioned (atleast in canon). The region at the circumference of the galaxy is referred to as the Wild Space, beyond which no one knows what exists.