Earth's axial tilt, also known as obliquity, is the angle between Earth's rotational axis and its orbital plane around the Sun. This tilt is approximately 23.5 degrees. It is responsible for the changing seasons as different parts of the planet receive varying amounts of sunlight throughout the year. As Earth orbits the Sun, the tilt causes the Northern and Southern Hemispheres to experience opposite seasons. For example, when the Northern Hemisphere is tilted toward the Sun, it experiences summer, while the Southern Hemisphere, tilted away, experiences winter. This axial tilt is a key factor in Earth's climate and weather patterns.