Physics – 6.1.1 The Earth | e-Consult

The Earth's orbit around the Sun is not perfectly circular; it's slightly elliptical. While the distance between the Earth and the Sun varies throughout the year, this variation is relatively small compared to the effect of the axial tilt. The more significant factor is the tilt itself.

Because of the 23.5-degree tilt, the angle at which sunlight strikes the Earth's surface changes throughout the year. During summer in the Northern Hemisphere, the Northern Hemisphere is tilted towards the Sun. This means the sunlight strikes the Northern Hemisphere at a steeper angle, concentrating the solar energy and resulting in longer daylight hours. Conversely, during winter in the Northern Hemisphere, the sunlight strikes at a shallower angle, spreading the solar energy over a larger area and resulting in shorter daylight hours.

The opposite occurs in the Southern Hemisphere. When the Northern Hemisphere is experiencing summer, the Southern Hemisphere is experiencing winter, and vice versa. The variations in daylight hours directly influence the amount of solar radiation received, which in turn determines the temperature and thus the season.