What causes the seasons on Earth?

What causes the seasons on Earth?

• A. The tilt of Earth's axis toward the Sun.
• B. The Moon's phases.
• C. The distance from the Sun.
• D. The shape of Earth's orbit.

Answer: (A)

Seasonal changes come from the tilt of Earth's axis relative to its orbit around the Sun. The axis is tilted about 23.5 degrees, so the Sun’s angle in the sky and the length of daylight change as Earth orbits. When a hemisphere tilts toward the Sun, sunlight hits more directly and days are longer, warming that hemisphere and producing summer. When that hemisphere tilts away, sunlight is more oblique and days are shorter, leading to winter. The opposite tilt causes the other hemisphere to experience opposite seasons. Distance to the Sun and the shape of Earth's orbit change a bit over the year, but these differences are small compared to the effect of the tilt, which is why they’re not the main cause of the seasons. Moon phases do not drive seasonal changes.

Seasonal changes come from the tilt of Earth's axis relative to its orbit around the Sun. The axis is tilted about 23.5 degrees, so the Sun’s angle in the sky and the length of daylight change as Earth orbits. When a hemisphere tilts toward the Sun, sunlight hits more directly and days are longer, warming that hemisphere and producing summer. When that hemisphere tilts away, sunlight is more oblique and days are shorter, leading to winter. The opposite tilt causes the other hemisphere to experience opposite seasons.

Distance to the Sun and the shape of Earth's orbit change a bit over the year, but these differences are small compared to the effect of the tilt, which is why they’re not the main cause of the seasons. Moon phases do not drive seasonal changes.