It largely explains why you can be so different to the other people you know who share your sun sign (does anyone else ever feel a bit ashamed when they discover a disliked celeb shares their sun sign?) The moon only stays in each sign for around two days, so it’s a much more variable aspect of your birth chart. Your sun sign dictates the brush strokes of your personality, your ‘outer self.' However, it’s your moon sign which reveals the REAL you, the private person inside that you know yourself to be. The earth takes 30-31 days to change signs as it orbits around the sun, so you share your sun sign with everyone born in that month-long time span. Your star (or sun) sign represents which sign the sun was in when you were born. You're probably up to date on your star sign (otherwise known as sun sign), but what about your moon sign? Here's everything you need to know. How does my moon sign relate to my star sign / sun sign?.How does my moon sign impact my relationships?.