Movie: A Green Flash Over Italy . ... Credit Copyright: Danilo Pivato ( Beyond the Moon ) Explanation: How could the Sun turn green? Difficult to observe, the momentary green flash above the rising or setting sun has been documented as a phenomenon caused by the atmospheric bending or refraction of sunlight. Like a weak prism , the Earth's atmosphere breaks white sunlight into colors, bending red colors slightly and green and blue colors through increasingly larger angles . ...