Princess Luna and Celestia once had a mom. The mom told Celestia she could be the main Princess for some time, but then later after some time said it was Luna's turn to be main Princess. Luna told Celestia, "Mom says it's my turn to be main princess". Celestia didn't like Luna or her mom and didn't want to give up her spot on the comfier couch so she zapped her and created the moon. Now, (mane) ponies sometimes look up to Luna and talk to her or ask her questions. All that is heard is "moon noises", which translates to whatever she may be saying. Unfortunately for Luna, everypony seems to confide their secrets with her and she has learned things she'd rather didn't.