CHAT GPT B L U E S K Y

EXTREMELY SMALL PARTICLES vs LARGER PARTICLES

Blue Day Sky (Siang Hari)
vs
Milky Night Sky (Malam Hari)

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☀ SIANG HARI — BLUE DAY SKY

Condition: Rayleigh Scattering (Favors Blue)

During the day, sunlight enters Earth's atmosphere. If the air contains extremely small particles:

• Air molecules (N₂, O₂)
• Nanometer-scale dust
• Particles much smaller than visible wavelengths (400–700 nm)

r ≪ λ → Rayleigh scattering occurs.

• Short wavelengths (blue) scatter more strongly
• Intensity follows: I ∝ 1/λ⁴

Result:

• Blue light spreads across the sky
• Sky appears deep blue
• Cleaner air → deeper blue

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🌙 MALAM HARI — MILKY NIGHT SKY

Condition: Mie Scattering (Favors Milky Glow)

At night, artificial light from cities interacts with larger particles:

• Pollution aerosols
• Smoke
• Water droplets
• Micrometer-scale dust

r ≈ λ or larger → Mie scattering dominates.

• All colors scatter more evenly
• Diffuse glowing effect
• Reduced star visibility

Result:

• Artificial light spreads in all directions
• Sky becomes pale, gray, orange, or milky

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🔬 Core Comparison Summary

Condition	Particle Size	Scattering Type	Sky Appearance
Extremely Small Particles	≪ Wavelength	Rayleigh	Blue Day Sky
Larger Particles	≈ or > Wavelength	Mie	Milky Night Sky

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Final Insight:
Extremely small particles → Rayleigh → Blue Sky (Siang Hari)
Larger particles + artificial light → Mie → Milky Night Sky (Malam Hari)