The temperature on Earth changes depending on the time of day and year primarily due to two factors: the rotation of the Earth on its axis and its orbit around the Sun.
Rotation of the Earth: The Earth rotates on its axis, resulting in the alternation of day and night. During the day, the Sun illuminates different parts of the Earth's surface, providing heat energy. As a result, the temperature rises. Conversely, during the night, the lack of direct sunlight causes a decrease in temperature as the Earth's surface radiates heat back into space.
Earth's Orbit around the Sun: The Earth orbits the Sun in an elliptical path, and its axis is tilted relative to its orbital plane. This tilt, known as the axial tilt or obliquity, is approximately 23.5 degrees. This tilt is responsible for the changing seasons.
- Summer: When a particular hemisphere is tilted towards the Sun, it receives more direct sunlight, leading to longer daylight hours and higher solar intensity. The increased exposure to sunlight causes temperatures to rise, resulting in summer in that hemisphere.
- Winter: Conversely, when a hemisphere is tilted away from the Sun, it receives less direct sunlight, resulting in shorter daylight hours and lower solar intensity. This reduced exposure to sunlight leads to lower temperatures, resulting in winter in that hemisphere.
- Spring and Autumn: During the transition periods between summer and winter, or vice versa, the axis of the Earth is neither tilted towards nor away from the Sun. This results in more balanced daylight hours and solar intensity, leading to milder temperatures. These transition periods are known as spring and autumn.
The combination of the Earth's rotation and its orbit around the Sun leads to the cyclic changes in temperature we experience throughout the day and year. It's worth noting that factors such as atmospheric circulation, ocean currents, topography, and local weather patterns also contribute to regional variations in temperature.