Question

The angle of inclination of the axis of rotation of Earth is:

• A. 22.0 degrees
• B. 22.5 degrees
• C. 23.0 degrees
• D. 23.5 degrees

Hint:

Earth's 23.5° axial tilt = main reason behind the seasonal variation.

Answer 1

The Correct Option is D

To determine the correct angle of Earth's axial inclination, let's examine this fundamental astronomical parameter:

1. Understanding Earth's Axial Tilt:
The axial tilt (or obliquity) is the angle between Earth's rotational axis and its orbital plane around the Sun. This tilt is responsible for Earth's seasons.

2. Current Measurement:
According to NASA and the International Astronomical Union:

• Current tilt: 23.5° (23°26' to be precise)
• This value is slowly decreasing (was about 24.2° in 3000 BC)
• Varies between 22.1° and 24.5° over a 41,000-year cycle

3. Why 23.5° is Correct:
This specific angle:

• Causes the Sun's apparent position to shift between the Tropics (Cancer and Capricorn)
• Creates the solstices when the tilt is most directed toward/away from the Sun
• Results in varying day lengths throughout the year

4. Importance of the Tilt:
The 23.5° inclination:

• Determines the Arctic and Antarctic Circles (90°-23.5° = 66.5°)
• Establishes the tropics at ±23.5° latitude
• Controls seasonal climate patterns globally

5. Why Other Options Are Incorrect:
While close, these values:

• Don't match current precise measurements
• Would significantly alter Earth's climate patterns if correct
• Don't correspond to any point in Earth's known obliquity cycle

Final Answer:
The correct angle of Earth's axial inclination is 23.5 degrees.