The Earth orbits the Sun in an elliptical path, meaning its distance from the Sun varies throughout the year. This variation in distance is responsible for the seasons, as the Earth’s tilt on its axis causes it to receive more or less direct sunlight at different times of the year.
Northern and Southern Hemispheres
The Earth is divided into two hemispheres: the Northern Hemisphere and the Southern Hemisphere. The seasons are opposite in these two hemispheres, so when it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere, and vice versa.
Summer
During summer, the Northern Hemisphere is tilted toward the Sun, so the days are longer and the Sun is higher in the sky. This means the Northern Hemisphere receives more direct sunlight, which heats up the land and air, causing warmer temperatures and longer daylight hours.
Winter
During winter, the Northern Hemisphere is tilted away from the Sun, so the days are shorter and the Sun is lower in the sky. This means the Northern Hemisphere receives less direct sunlight, which causes the land and air to cool down, resulting in cooler temperatures and shorter daylight hours.
Equinox and Solstice
The four seasons are marked by two equinoxes and two solstices. The equinoxes occur in the spring and fall when the Earth’s axis is not tilted toward or away from the Sun, resulting in equal day and night lengths. The solstices occur in the summer and winter when the Earth’s axis is tilted the most toward or away from the Sun, leading to the longest day and shortest night (summer) and the shortest day and longest night (winter).
In summary, the seasons are caused by the Earth’s orbit around the Sun and the tilt of its axis, which results in varying amounts of direct sunlight reaching different parts of the Earth throughout the year.