 What mercury being in retrograde means to astrologists, scientists, and your roommate? The planet mercury rules communication. During the time that it's in retrograde or moving backwards, wires get crossed and miscommunications tend to happen. Well, actually that part where it's moving in reverse is an optical illusion. And even if it did move backwards, we're too far away for it to actually affect us. Those are all great theories, but I know for a fact that mercury in retrograde is the reason my rent was late. I was late to work, I got a parking ticket, and why my boyfriend won't text me back.