Have you ever observed the sky just before sunrise?
The Science Behind the Sky's most beautiful hour
long before the sun clears the horizon, the sky puts on a show few people are awake to see ;
a slow shift from black to blue to gold. It isn't magic, it's physics.
As the sun climbs from 18° below the horizon toward sunrise, the sky moves through three twilight stages, each brighter than the last, culminating in the vivid oranges and pinks of civil twilight.
Those colors come from Rayleigh scattering. Sunlight contains every color, but gas molecules in the atmosphere scatter shorter wavelengths (blue) more than longer ones (red, orange).
Before sunrise, light travels through much more atmosphere at a low angle, scattering away nearly all the blue and leaving the warm colors behind.
High clouds can amplify the effect, reflecting that low-angle light like a screen, while cooler,
