What phenomenon is primarily responsible for causing the seasons on Earth?

The tilt of Earth's axis is the primary phenomenon responsible for causing the seasons. The Earth is tilted at an angle of about 23.5 degrees relative to its orbit around the Sun. This tilt means that as the Earth travels around the Sun, different parts of the planet receive varying amounts of sunlight at different times of the year.

During summer in the northern hemisphere, for example, the North Pole is tilted towards the Sun, resulting in longer days and more direct sunlight, which warms that region. Conversely, during winter, the North Pole is tilted away from the Sun, leading to shorter days and less direct sunlight, causing cooler temperatures. This cycle creates the seasonal changes we experience throughout the year.

Factors like the distance from the Sun and the Earth's orbit do influence climate and temperature to a degree but are not the primary reasons for seasonal changes. The rotation of Earth affects day and night but not the seasons. The varying speed of the Earth's orbit plays a minimal role in seasonal changes compared to the consistent effect of the axial tilt.