What causes the seasons on Earth?

The seasons on Earth are caused by the tilt of Earth’s axis and its orbit around the Sun. Here’s how these factors contribute:

1. Tilt of Earth’s Axis:
   • Earth’s axis is tilted at an angle of about 23.5 degrees relative to its orbit around the Sun. This tilt means that different parts of Earth receive varying amounts of sunlight throughout the year.
2. Earth’s Orbit:
   • As Earth orbits the Sun, the tilt causes the Northern and Southern Hemispheres to experience different seasons at different times of the year. The orbit is elliptical, but Earth’s axial tilt plays the primary role in creating the seasons.

The Four Seasons:

• Spring: Occurs when the Earth’s axis is not tilted toward or away from the Sun, resulting in roughly equal day and night lengths (the vernal equinox).
• Summer: The hemisphere tilted toward the Sun receives more direct sunlight, leading to warmer temperatures.
• Autumn (Fall): The Earth’s axis is again not tilted toward or away from the Sun, leading to another period of equal day and night lengths (the autumnal equinox).
• Winter: The hemisphere tilted away from the Sun receives less direct sunlight, leading to colder temperatures.

Key Points:

• Northern Hemisphere experiences summer when it is tilted toward the Sun (around June to September) and winter when it is tilted away (around December to March).
• Southern Hemisphere experiences opposite seasons to the Northern Hemisphere due to its opposite tilt.

The Earth’s axial tilt causes the variation in sunlight during the year, which, in turn, causes the changing seasons.