The zodiac signs no longer line up with the constellations they're named after. They slipped about a whole sign over two thousand years.

Earth's axis wobbles like a spinning top, one full circle every 25,772 years. That is precession. Western astrology fixed its signs to the seasons rather than the stars, so the label and the actual backdrop have drifted apart. When an app says the Moon is in Aries, the stars behind it are usually Pisces.