Earth’s axis

Earth's axis is tilted at approximately 23.5 degrees relative to its orbital plane around the Sun. This tilt, believed to be caused by a massive collision early in Earth's history, is the primary reason for the seasons. As Earth orbits the Sun, different hemispheres receive more direct sunlight, leading to warmer temperatures and longer days in summer, and less direct sunlight in winter. The Moon's gravitational pull helps stabilize this axial tilt over time.12

While the Earth's axis has a stable tilt, it also experiences a slight wobble, known as polar motion, with periods of about 14 and 12 months, causing the poles to shift over a roughly 6.5-year cycle. Separately, the magnetic poles of the Earth have migrated across the surface over geologic time, a phenomenon known as polar wandering, which has provided evidence for continental drift.34