system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are we told the universe is expanding and that the galaxies are moving away from us and also told our galaxy will collide with andromeda?
gpt
We are told this because the universe is expanding and that galaxies BEYOND a certain distance are all moving away from us and that because the Andromeda galaxy is much closer than this distance AND that we're both moving towards each other that we'll collide.  

The universe is expanding.  However, at "close" enough distances forces such as gravity can overcome the expansion.  It's how even though the universe is expanding you can still clap your hands together.  There's just not enough expansion between your hands to prevent you from doing that.