Mercury doesn't actually reverse course in space. Retrograde is an optical illusion, the same one that happens when a faster car passes a slower one on the highway: for a stretch, the car behind briefly appears to move backward relative to the one in front, even though both are moving forward the whole time.

Mercury orbits the sun faster than Earth does, so several times a year Earth catches up and briefly passes it. From our vantage point, Mercury appears to slow down, stop, and drift backward through the zodiac before resuming its normal path forward. The planet never actually stops. We're just watching from a moving train.

Mercury retrograde gets blamed for canceled flights, dropped calls, and miscommunication, and honestly, some of that reputation is earned. Mercury rules communication, travel, and technology, and those do tend to feel glitchier during this window, whether that's the planet or just heightened attention to normal chaos is an open question.

The more useful frame is what the window is actually good for. It's a strong stretch for rereading a contract before signing, reconnecting with an old friend, revisiting a decision you rushed, or backing up your files before you travel. Retrograde doesn't create new problems so much as it surfaces ones already sitting there, unfinished. Treat it as a prompt to slow down and double check, not a reason to put your life on hold.