Which phenomenon is primarily responsible for the fuzzy glow, or halo, observed around a full moon on a humid night?

• A. Scattering of moonlight by dust particles in space
• B. Diffraction of moonlight by tiny water droplets or ice crystals in the $E’arth’s$ atmosphere
• C. Reflection of moonlight from the surface of the moon itself
• D. Refraction of moonlight through the $E’arth’s$ atmosphere

Answer: (B)

Verified step by step guidance

1. Understand that the fuzzy glow or halo around the full moon is an optical phenomenon caused by the interaction of moonlight with particles in the Earth's atmosphere.
2. Recognize that scattering by dust particles in space or reflection from the moon's surface would not create a halo effect visible from Earth; these phenomena do not produce the characteristic ring or glow around the moon.
3. Consider refraction, which is the bending of light as it passes through different media; while refraction affects the apparent position of celestial objects, it does not typically create a halo around the moon.
4. Identify diffraction as the bending and spreading of light waves when they encounter small obstacles or openings, such as tiny water droplets or ice crystals in the Earth's atmosphere.
5. Conclude that the halo is primarily caused by diffraction of moonlight by these tiny water droplets or ice crystals, which scatter the light in a way that produces the observed fuzzy glow or halo.