Why do the southern and northern hemisphere have different seasons?

The southern and northern hemispheres experience different seasons due to the tilt of the Earth's axis. As the Earth orbits the Sun, the hemisphere tilted toward the Sun experiences summer, receiving more direct sunlight and longer days, while the opposite hemisphere, tilted away, experiences winter with less direct sunlight and shorter days. This axial tilt remains constant as the Earth revolves around the Sun, leading to the cyclical nature of the seasons. Thus, when it's summer in the north, it's winter in the south, and vice versa.