STEM与日常科技·英语30篇（3）

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瑞利散射与天空颜色

Sunlight contains all visible colors, but nitrogen and oxygen molecules scatter shorter blue wavelengths far more strongly than red ones.
This Rayleigh scattering happens because molecule size is much smaller than light’s wavelength—especially for blue light.
At noon, the sky looks deep blue because sunlight travels a short path through atmosphere, maximizing blue scatter.
Near sunrise or sunset, light passes through thicker air, so most blue gets scattered away before reaching your eyes.
What remains—longer orange and red waves—paints clouds and mountains with warm, dramatic tones.
On Mars, fine rust dust particles are larger, so they scatter red light more: hence its butterscotch-colored sky.
Polarized sunglasses work partly by blocking horizontally scattered blue light, reducing glare from water or roads.
Even though air seems ‘empty’, its invisible molecules constantly reshape how we see light across Earth and beyond.